07Plumbing

223 illustrations · printed pages 257-300

Supply Plumbing ·Flow and Pressurep. 258

1508

Constant water flow (velocity) can wear out pipes

· p. 259

A basement cross section shows a gas water heater connected to cold-water supply piping, hot-water distribution piping, and a hot-water recirculating loop. Arrows indicate flow through the supply, heater, and pumped return loop, which connects to the heater's cold-water inlet piping through a check valve. The incoming water service has a main shutoff valve near the basement floor. An annotation warns that constant circulation can prematurely wear out thin-wall Type M copper piping; no actual pipe perforation or leak is drawn.

1509

Pressure decreases with height

· p. 259

A house cross section shows a water supply pipe entering at the basement and rising to fixtures on three floors. Pressure callouts decrease from 60 PSI at the supply entry to 58 PSI at the basement fixture, 55 PSI at the first-floor fixture, 51 PSI at the second-floor fixture, and 47 PSI at the third-floor fixture. Elevation marks indicate heights from 0 to 30 feet. An annotation states that 1 PSI will make water rise 2.31 feet, and another recommends testing water pressure at the highest point in the house for the most meaningful results.

Supply Plumbing ·Private Water Sourcesp. 260

1510

Larger diameter pipe to water heater

· p. 260

A basement cross section shows a gas-fired storage water heater connected to hot- and cold-water supply piping beneath the floor framing. The incoming cold-water line rises beside the foundation wall through a main shutoff valve and branches down to the water heater through another valve. The cold-water feed to the heater is depicted with larger-diameter piping than the hot-water outlet, with reference samples labeled 3/4-inch and 1/2-inch copper pipe. Arrows indicate cold water flowing toward the distribution piping and into the heater, and hot water flowing upward from the heater to the hot-water distribution line. A gas supply connection, a short top vent connection, and a side-mounted relief valve with a discharge pipe are also shown.

1511

Pressure decreases with height

· p. 260

A house cross section shows a water supply pipe entering at the basement level and rising to serve fixtures on three floors above. Pressure callouts decrease from 60 PSI at the 0-foot entry elevation to 58 PSI at the basement fixture, 55 PSI at 12 feet, 51 PSI at 21 feet, and 47 PSI at 30 feet. Elevation marks and floor labels relate the fixture heights to the supply entry. An annotation states that 1 PSI will raise water 2.31 feet, and another recommends testing water pressure at the highest point in the house for the most meaningful results.

1512

Drawdown test

· p. 260

The cross section depicts a well undergoing a drawdown test, with a surface pump lifting water through a pipe and discharging it onto the ground. A foot valve is shown at the submerged lower end of the pipe inside the well casing. The initial water table and the lowered water level during pumping define the drawdown, with a cone-shaped depression in the surrounding groundwater surface. Annotations explain that greater drawdown indicates lower well capacity and that a strong supply produces relatively little water-level drop. A boxed note describes recovery testing after pumping stops and states that a recovery rate of 3 gallons per minute is considered acceptable in many areas.

1513

Dug wells

· p. 260

The illustration shows cross sections of two dug wells, one with an older stone casing and the other with a segmented concrete casing. Both have covers with access hatches and extend below the water table, with water occupying their lower portions. The ground is shown sloping away from the well openings, and a minimum 12-inch clearance is indicated between grade and the top of the concrete casing. The concrete well is labeled as 2 to 3 feet in diameter, with a usual depth of less than 30 feet. Its casing joints in the upper 8 feet are specified to be watertight.

1514

Bored wells

· p. 260

The illustration shows a cross section of a bored well with a segmented concrete casing, a cover, and an access hatch. The well is labeled as 2 to 3 feet in diameter with a usual depth of 50 to 100 feet, and water occupies the casing below the water table. The casing projects at least 12 inches above the surrounding ground, which slopes away from the well. An annotation specifies that casing joints in the top 8 feet should be watertight.

1515

Drilled wells

· p. 260

The cross section depicts a drilled well near a house, extending through soil and impervious rock into water-bearing rock below the water table. The well is labeled as 4 to 6 inches in diameter and 50 to 900-plus feet deep. Two enlarged details show concrete around the casing near the surface and gravel around the casing where it reaches bedrock. The casing ends at bedrock, while the drilled bore continues down into the water-bearing formation.

1516

Casings for drilled wells

· p. 261

The cross section shows a drilled well extending through soil and impervious rock into water-bearing rock below the indicated water table. The casing lines the upper portion of the well, with annotations stating that it is only required down to bedrock and ends at bedrock. One enlarged detail shows concrete surrounding the casing in the soil. A second enlarged detail shows gravel outside the casing above the bedrock interface. An annotation lists steel, plastic, brass, copper, and fiberglass as possible casing materials.

1517

Well pits

· p. 261

The illustration compares two private well arrangements using a covered well pit below ground level. A cross section shows the well extending below the water table, with a foot valve on the submerged intake pipe and the supply line to the house below the indicated frost line. Option A places the pump and pressure tank inside the house, connected to the well and the house fixtures. Option B places both the pump and pressure tank within the well pit, with an outlet pipe running to the house. No specific defect is marked.

1518

Static head

· p. 261

A cross section shows a drilled well beside a house extending through soil and impervious rock into water-bearing rock below the water table. A circular enlargement shows the water level, pump intake, and bottom of the well. A vertical double-headed arrow identifies static head as the vertical distance from the water level to the pump intake. The well continues below the intake, distinguishing static head from the full water depth in the well. No defect or improper installation is depicted.

1519

Well location

· p. 261

The illustration is a plan view showing a house, a septic tank, a tile bed, and a separate water well. A pipe connects the house to the septic tank and continues to the tile bed distribution piping. Dimension arrows indicate a minimum separation of 50 feet between the well and the septic tank. The indicated minimum separation between the well and the tile bed is 50 feet if the well has a casing, or 100 feet if it has no casing.

1520

Deep wells and shallow wells

· p. 261

A ground cross section beneath a house compares deep and shallow private water wells. The deep well, labeled more than 25 feet deep, extends through soil and impervious rock into underlying water-bearing rock. The shallow well, labeled 25 feet or less in depth, terminates in a near-surface water zone above the impervious rock. A water-table marker identifies the upper surface of the shallow water zone. The illustration explains the relative depths and geological settings without depicting installation defects.

1521

Foot valve

· p. 261

A cross section shows a well with a submerged suction-line intake and foot valve connected to an aboveground pump. Two enlarged details illustrate the valve during pump operation and when the pump is off. During operation, suction opens the foot valve and water flows upward through the suction line. When the pump stops, a spring closes the valve, retaining water in the suction line. A strainer surrounds the intake, and an annotation notes that a check valve in the suction line may be used instead of a foot valve at the intake.

1522

Types of pumps

· p. 262

The illustration shows three pump arrangements for private well water supplies. The two-line deep-well jet pump sits above the well and circulates water down to a jet in the well, where venturi action draws in well water for return to the pump and delivery to the house. The one-line shallow-well jet pump has its jet at the aboveground pump, with an inlet from the well and an outlet to the house. The deep-well submersible pump is positioned within the water-filled well casing and pushes water upward through a discharge pipe; it is labeled as the most powerful type. Arrows indicate water flow through each arrangement.

1523

Jet pump

· p. 262

A cutaway view shows a single-pipe jet pump with an electric motor connected to the pump assembly. The exposed housing reveals the impeller, nozzle, and venturi, with an inlet from the well at the front and a discharge connection at the top. Colored arrows trace water flow through the pump and the internal circulation identified as priming the pump. Notes identify this single-pipe design as the most common pump used on shallow wells and state that two-line jet pumps are used for deep wells.

1523.5

Types of deep well jet pumps

· p. 262

The illustration compares a twin-pipe deep well jet pump system with a packer single-pipe deep well jet pump system. Both have an aboveground pump supplying water to the house and an ejector located down in the well. The twin-pipe arrangement shows separate suction and drive pipes passing through a well seal plate to a deep well ejector, with a 4-inch dimension across the well. The packer arrangement shows a suction pipe inside a well casing that acts as the drive pipe, a packer ejector below, and a 2-inch dimension across the casing. Arrows indicate water traveling down the drive passage toward the ejector and returning upward through the suction pipe.

1524

Shallow well with single line jet pump

· p. 262

The illustration shows a shallow well connected by a single suction line to an indoor jet pump and pressure tank. The suction pipe extends down the well casing to a foot valve below the water table and exits through a pitless adapter below ground level. Dimension arrows identify static head and a total depth of less than 27 feet, the stated limit for this arrangement. Flow arrows trace water from the well through the pump and into the distribution line serving house fixtures, with the pressure tank connected to that line. An enlarged check-valve cross section explains that a check valve can replace the foot valve, with two possible locations indicated along the suction piping.

1525

Deep well pumps

· p. 262

The illustration compares a twin-pipe deep-well system with a packer single-pipe deep-well system. Both show a pump and pressure tank inside a house, connected through a well pit to piping extending below the water table. The twin-pipe arrangement has two pipes descending into a well marked 4 inches, while the packer arrangement uses a single-pipe configuration in a well marked 2 inches. Arrows indicate flow through the well piping and along the supply piping to house fixtures. A water seal plate is identified at the top of the twin-pipe well; no defects are indicated.

1526

Piston pump

· p. 262

The illustration shows a belt-driven piston pump used in older private well-water systems. A motor drives a large pulley and crank linkage, converting rotary motion into reciprocating piston movement inside the pump cylinder. The cylinder has separate inlet and outlet passages with valves controlling water flow. The main view and three circular details show successive piston positions: inward travel discharges water through the outlet valve, while outward travel draws water through the inlet valve. Arrows indicate pulley rotation, piston travel, and water-flow direction.

1527

Drilled well with submersible pump

· p. 263

A cross section shows a drilled well extending through soil into bedrock, with a submersible pump below the resting water level supplying a house. Enlarged details show the capped steel casing, slurry seal, pump wiring, and pitless adapter connecting the vertical pipe to the buried pipe to the house. The casing extends into bedrock, and water enters the lower well through cracks in the rock. A check valve is located above the pump, and clearance below the pump prevents mud pickup from the well bottom. Dimension arrows identify well depth, air above the water, static head, and pump clearance; a note describes a safety cable used to prevent loss of the pump if connections come apart.

1527.5

Submersible pump setup

· p. 263

The illustration shows the pressure-tank and control assembly for a submersible well pump system. Water enters from the pump through the lower-left pipe, passes the tank connection and valve assembly, and flows toward the house through the right-hand riser, as indicated by arrows. A pressure gauge, drain valve, and relief valve are mounted at the tank piping. A pressure switch above the piping has electrical connections labeled to the pump and from the power source. A cutaway of the pressure tank shows water inside; no defects are indicated.

1528

Pressure tank components and pump controls

· p. 263

The illustration shows a well-water pressure tank in cutaway, with air above water and a connection to the distribution piping below. Numbered callouts identify the tank, pressure relief valve, pressure gauge, pressure switch, main water shutoff valve, and air volume control. Flow arrows indicate water arriving from the pump and well and continuing to house fixtures. An electrical panel supplies a switch and the pressure-switch control circuit, with power continuing to the pump or pump relay switch. An air volume control connects to the suction side of the pump; the annotations explain short-cycling protection and typical pump cut-in and cut-out pressure settings.

1529

Bladder-type pressure tank

· p. 263

Four sequential diagrams show the operation of a bladder-type pressure tank connected to a well pump, pressure switch, and outlet faucet. Panel A shows the initial installation state with 30 PSI air pressure, the pump off, and the water outlet closed. Panel B shows the pressure switch activating the pump, with water entering beneath the diaphragm and air at 40 PSI. Panel C shows the pump running until the tank is filled and the pressure switch is satisfied, with both air and water labeled 50 PSI. Panel D shows water discharging from the open faucet under tank pressure while the pump is off, with air pressure reduced to 45 PSI. A note states that the pressures shown are approximate.

Supply Plumbing ·Public Water Servicep. 264

1529.5

Air volume control

· p. 264

The illustration shows a sectional view of an air volume control connected to a pressure tank. A flexible diaphragm separates the air chamber on the left from a water-filled chamber containing a spring on the right, which connects to a vacuum line. Arrows show air entering through the bottom inlet and discharging through a side connection into the pressure tank. The annotations explain that pump operation reduces water pressure and moves the diaphragm right to draw in air; when the pump stops, increased water pressure moves the diaphragm left and pushes air into the tank.

1530

Waterlogged pressure tank - short-cycling

· p. 264

Three cutaway pressure-tank views show normal drawdown from 40 PSI with the pump off, through 30 PSI, to the 20 PSI pump cut-in point. As water leaves the tank, the air cushion expands and the water level falls. Condensation or stains on the tank exterior indicate the normal water level. A fourth view contrasts a waterlogged tank with a high water level and insufficient air, connected to piping from the pump and well and onward to house fixtures. The annotations explain that loss or absorption of air can cause rapid pump short-cycling and contrast normal drawdown time with repeated 5- to 10-second cycles.

1531

Service piping - when different types were used

· p. 264

This timeline charts the use of water service piping materials from 1900 through 2010. Bars show lead through approximately 1940, brass through the mid-1930s, and galvanized steel through 1950, with copper beginning in the early 1940s and continuing to the chart's endpoint. Plastic piping bars begin later: polyethylene in the mid-1960s, PVC near 1970, polybutylene in the late 1970s, and PEX around 1995. An annotation states that PEX began to be used in North America as polybutylene failures were reported and became popular around 1995. The illustration presents historical material-use periods rather than a physical piping installation.

1532

Separate water service from sewer pipe

· p. 264

The illustration shows a cutaway of a buried water service and sewer pipe within a stepped trench. The smaller water service pipe rests on a soil shelf above and laterally offset from the larger sewer pipe at the bottom of the trench. A dashed line marks frost depth, with the water service shown 6 to 12 inches below that line. A separate dimension indicates 12 to 20 inches of vertical separation between the water service and sewer pipe. The arrangement depicts separation of the potable water service from the sewer.

Supply Plumbing ·Distribution Piping In the Housep. 265

1533

Main shutoff valve - stop and waste

· p. 265

A foundation cross section shows the incoming water supply passing through a main shutoff valve and water meter before rising to the cold-water distribution piping. A branch supplies a gas water heater, with separate hot-water piping leaving the heater. An enlarged detail shows a stop-and-waste shutoff valve with a bleed valve downstream of the shutoff, allowing supply piping to be drained for repairs. Notes state that these valves are not full bore, are uncommon in new installations, and are not permitted in all jurisdictions. The illustration warns against installing them where they may become submerged because the waste opening creates a potential cross connection.

1534

Globe valve

· p. 265

Two sectional drawings show a globe valve in closed and open positions within a water supply pipe. The handle operates a threaded spindle that raises or lowers a stem washer against the valve seat. In the closed position, the washer seals the opening; in the open position, it is lifted to allow water through the offset passage. A packing nut and packing washer surround the spindle near the handle. Arrows indicate left-to-right water flow, and an annotation explains that globe valves restrict flow but can be used for throttling.

1535

Gate valve

· p. 265

Two sectional views show a gate valve in its fully closed and fully open positions on a horizontal water supply pipe. In the closed view, the gate extends across the pipe bore and blocks water flow. In the open view, the gate is raised into the valve body, leaving the full bore clear for flow. The handle operates a threaded spindle, with a packing nut and packing washer surrounding the stem above the body. Annotations identify use on mains and water heaters, specify fully open or fully closed operation, and warn that corrosion of the metal-to-metal seal can cause valve failure.

1536

Ball valve

· p. 265

Two simplified sectional views depict a full-bore ball valve in closed and open positions in a water supply pipe. In the closed view, the handle is perpendicular to the pipe and the ball blocks flow through the valve. In the open view, the handle is parallel to the pipe and the ball's bore aligns with the pipe, allowing water to flow through. A spindle connects the handle to the ball. The annotations identify applications at water mains and water heaters and explain that ball valves restrict flow less than other valve types.

1537

Pressure regulator required

· p. 265

The illustration shows a street water supply entering beneath a foundation footing and rising into a basement. Flow arrows indicate water passing through a main water shutoff valve, a water meter, and then a pressure regulator before continuing into the house distribution piping. An annotation states that residential systems with static pressure above 80 PSI usually have a pressure regulator, typically set at 50–60 PSI. A callout specifies a strainer upstream of the regulator and notes that it is often integral to the regulator. The foundation wall, footing, basement slab, and a floor drain are shown for context.

1538

Types of copper supply pipe

· p. 265

Three open-ended sections of nominal 1/2-inch copper supply pipe compare Types M, L, and K, each with a .625-inch outside diameter. Their wall thicknesses increase from .028 inch for Type M to .040 inch for Type L and .049 inch for Type K. Identification lettering is shown in red, blue, and green respectively. The annotations identify Type M for general plumbing, not underground, in hard temper only; Type L for general plumbing and heating in soft or hard temper; and Type K for underground service as well as plumbing, heating, and gas lines in soft or hard temper.

1539

Soldered pipe connection

· p. 266

The illustration shows a soldered 90-degree supply elbow connecting vertical and horizontal copper pipes. A cutaway at the horizontal connection reveals the overlapping pipe and fitting, with an arrow indicating solder flow into the joint. A torch flame heats the rear of this joint to draw solder into the connection. An annotation states that the joint must first be cleaned and coated with flux for solder to flow and adhere properly. Solder is also identified at the vertical pipe-to-elbow connection.

1540

Flare fitting

· p. 266

The illustration presents cross-sectional views of a flare fitting and its assembly sequence. Step A shows a flare nut slipped over a straight pipe, and step B shows the pipe end flared outward with a flaring tool. Step C shows the nut tightened onto a threaded nipple, capturing the flared plastic pipe end against the fitting. The nipple is shown joined to a copper pipe by a soldered connection, with a separate detail illustrating that joint. An annotation states that flare fittings can connect plastic and/or copper pipes to each other or to fixtures.

1540.5

Joints and fittings - alternatives to soldering

· p. 266

The illustration shows two alternatives to soldered joints in water distribution piping. On the left, a SharkBite® push-fit coupling accepts copper, CPVC or PEX pipe, with arrows indicating that the pipe is pushed and twisted into the fitting. A grab ring holds the pipe in place, while an O-ring creates the seal. On the right, a ProPress® coupling joins copper pipe using a special press tool, with compressed O-rings providing the seal. The press tool is shown around the fitting, and a green Smart Connect® feature is identified below it.

1541

Compression fitting

· p. 266

The illustration shows a compression fitting connecting a supply tube to a toilet shutoff valve. An exploded view shows the supply tube passing through a compression nut and compression ring into the threaded valve connection. A circular cross section shows how the nut confines the compression ring around the tube at the valve body. A side view of a toilet locates the shutoff valve below the tank, between the wall supply piping and the vertical tank supply tube. No defects or improper installation practices are depicted.

1542

Galvanized steel pipe

· p. 266

The illustration shows a transverse cross section and a longitudinal cutaway of galvanized steel water-supply pipe. Rust deposits line the interior and substantially narrow the passage available for water flow. Both views show water spraying through holes in the pipe wall. The longitudinal view includes a threaded end, and the annotations identify hot-water pipes, horizontal pipes, and thinner threaded sections as locations likely to develop problems first.

1543

Dielectric union

· p. 266

The illustration shows an exterior view and a longitudinal section of a dielectric union connecting copper pipe to galvanized steel pipe. The section identifies a soldered connection at the copper female shoulder and a threaded connection at the galvanized male shoulder. A galvanized nut holds the union together, while a plastic insulating sleeve and washer separate the dissimilar metals. The annotation recommends this arrangement to prevent corrosion where copper and galvanized steel supply piping meet.

1544

Hangers for copper pipe

· p. 267

The illustration shows copper distribution piping supported alongside a wood joist on nails, with a separate detail of a steel pipe hanger. The nail supports are identified as improper because contact with incompatible metals can cause localized deterioration of the pipe or hanger. The steel hanger detail shows insulating tape at the pipe-contact area and instructs that steel hangers must be insulated. The accompanying text specifies brass or copper hangers as the preferred supports for copper pipe.

1545

Cross connections

· p. 267

The illustration compares plumbing cross-connection hazards and corrective measures at a bidet, an older bathtub, and a laundry tub. The bidet has a submerged nozzle, with installation of a vacuum breaker identified as the solution. The bathtub has a low spout below the illustrated water level, and fixture replacement is recommended. The laundry tub comparison shows a spout below the flood level rim versus a replacement faucet providing an air gap above the rim. An annotation specifies a hose bibb vacuum breaker for a hose-threaded spout above the rim, and the introductory text explains the risk of contaminated water being siphoned into the potable supply under negative supply pressure.

1546

Air gap

· p. 267

The illustration shows a cross-section of a kitchen sink installed in a countertop, with a faucet above and a drain trap below. The sink is filled with water to the indicated high water level at its rim. A vertical double-headed arrow identifies the air gap between the faucet outlet and this water level. This open separation protects the water supply from back-siphonage of sink water. The sink drain connects through a vertical tailpiece to a P-trap and horizontal waste pipe.

1547

Atmospheric vacuum breaker

· p. 267

The illustration shows an outside faucet supplied by a pipe passing through a wall. An atmospheric vacuum breaker is installed between the faucet outlet and a hose. The hose extends into a bucket partially filled with water, with its open end submerged below the water surface. The submerged hose end is identified as a potential cross connection; the vacuum breaker provides protection against backsiphonage into the water supply.

1548

Pressure type vacuum breaker

· p. 267

The illustration shows a pressure-type vacuum breaker installed on an elevated piping loop serving a lawn irrigation system. Arrows indicate supply water rising to the vacuum breaker and descending into the irrigation piping. An enlarged section shows normal operation with the valve open and water flowing from the bottom inlet to the side outlet. A second section shows a backflow condition, with the valve closed and air entering through the top vent and passing toward the outlet. The installation drawing also includes shutoff valves, a hose faucet, and an irrigation outlet.

1548.5

Dual check valve assembly

· p. 267

Two sectional views show a dual check valve assembly with two spring-loaded check valves arranged in series inside a common housing. In the upper view, normal water flow travels from left to right with both check valves open. In the lower view, a backflow condition is illustrated with water directed from the right and both check valves closed to prevent reverse flow. A note states that the mechanism is simplified for clarity.

1549

Double check valve assembly

· p. 268

Two cutaway views depict a double check valve assembly with upstream and downstream handwheel-operated valves, two spring-loaded check valves in series, and four test ports. The upper view shows normal operation, with both check valves open and water flowing from left to right. The lower view shows a backflow condition, with reverse flow entering from the right and both check valves closed to prevent upstream backflow. A note states that the mechanism is simplified for clarity.

1550

Reduced pressure backflow assembly

· p. 268

Two simplified cutaway diagrams show a reduced pressure backflow assembly between upstream and downstream shutoff valves. During normal operation, water flows from left to right through open primary and secondary check valves, while the atmospheric vent remains closed. In the backflow condition, the flow arrow points toward the assembly from the downstream side and both check valves are closed. The atmospheric vent opens, allowing residual water to discharge through the vent port. The diagrams compare operating states rather than proper and improper installations.

1550.5

Backflow preventer with atmospheric vent

· p. 268

Two sectional diagrams show a backflow preventer with two spring-loaded check valves and an atmospheric vent beneath the intermediate chamber. During normal operation, both check valves are open and arrows show water flowing from left to right. Under the backflow condition, an arrow shows water entering from the right, and both check valves are closed to block reverse flow. The vent connection is shown below the chamber in both diagrams. A note states that the mechanism is simplified for clarity.

1551

2 ways to reduce risk of backflow into dishwasher

· p. 268

· p. 270

The illustration shows a cutaway of an oil-fired storage water heater with an external oil burner firing into a refractory-lined combustion chamber below the tank. A central flue containing a twisted baffle (turbulator) passes upward through the tank and connects to the vent connector at the top. The cold-water inlet has a supply valve and an internal dip tube extending toward the bottom of the tank, while the hot-water outlet exits at the top. Insulation surrounds the tank, and a sacrificial anode rod hangs inside it. A side-mounted temperature/pressure relief valve connects to a downward discharge pipe, and a drain valve is located near the bottom.

Water Heaters ·Gas Piping, Burners and Ventingp. 271

1562

Gas water heater

· p. 271

A cutaway drawing shows a storage-type gas water heater with an insulated tank and a burner beneath it. The cold-water supply connects to a dip tube extending toward the bottom of the tank, while the hot-water outlet leaves the top. A central flue containing a baffle carries combustion gases upward to the draft hood and vent connector. The gas supply includes a sediment trap and gas valve, with thermostat control, pilot light, and thermocouple shown near the burner. A sacrificial anode rod, temperature/pressure relief valve with discharge pipe, and lower drain valve are also identified.

1563

External (floating) tank water heater (oil-fired)

· p. 271

A cross section shows an oil-fired water heater with an internal water tank surrounded by an external combustion-gas passage. An oil burner fires into a refractory-lined chamber beneath the tank, and arrows show hot gases rising around the tank sides and exiting through a vent connector near the top. Cold water enters at the top and travels down a dip tube, while hot water leaves through a separate top outlet. Insulation is shown along the outer enclosure. A note states that the pressure relief valve is not shown.

1564

Dip tube

· p. 271

A cutaway view of a gas-fired storage water heater shows the dip tube extending from the top cold-water inlet to near the bottom of the tank. Arrows indicate cold water entering at the top, discharging near the bottom, and circulating upward as it is heated. Hot water exits through a separate outlet at the top. A gas pipe and gas valve supply the burner beneath the tank, and a central flue extends upward through the stored water to the vent above. No defect is depicted.

1565

Sacrificial anode

· p. 271

A cutaway view of an electric storage water heater shows a sacrificial anode rod suspended vertically inside the tank from its top. A dashed outline emphasizes the rod, and the annotations explain its corrosion-protection function, typical magnesium construction, and replacement when badly corroded. The top has a hot-water outlet and a cold-water inlet with a shutoff valve. Two heating elements, exterior access covers, an electrical supply connection, a side-mounted relief valve with discharge pipe, and a bottom drain valve are also visible. No actual corrosion damage or installation defect is depicted.

1566

Recovery rate

· p. 272

Two cutaway views of an electric storage water heater illustrate recovery rate as water is heated from 50°F to 140°F. Each tank shows a top-mounted cold-water inlet with a dip tube extending toward the bottom, a hot-water outlet, and upper and lower electric heating elements. Blue water in the left tank and red water in the right tank indicate the temperature change, with arrows and a clock between them representing elapsed heating time. The annotation describes recovery rate as the number of gallons that can be heated to 140°F in one hour, giving 35 gallons per hour as an example.

1567

Electric water heater

· p. 272

The illustration shows a cutaway of a cylindrical electric storage water heater with an insulated tank and outer jacket. Hot water exits at the top beside a cold water inlet fitted with a supply shutoff valve. Upper and lower electric heating elements project into the tank, with side access panels and a labeled thermostat control/high temperature limit switch. A sacrificial anode rod extends downward inside the tank. A side-mounted temperature/pressure relief valve connects to a downward discharge pipe, and a drain valve is located near the bottom.

1567.5

Tempering (mixing) valve on water heater

· p. 272

The illustration shows a water heater with a tempering valve connecting its hot-water outlet to a branch from the cold-water inlet. Blue piping carries 50°F cold water into the tank and toward the mixing valve, while red piping carries 150°F water from the tank to the valve. The valve delivers mixed water at 120°F through an orange outlet leading to plumbing fixtures. A shutoff valve is shown on the cold-water supply upstream of the branch, and a vent rises from the center of the water heater.

1568

Electric water heater - element sequencing

· p. 272

Four cutaway views show the operating sequence of a dual-element electric storage water heater, with red indicating warm water and blue indicating cold water. In stage A, hot water is being drawn and incoming cold water reaches the tank bottom through a dip tube, causing the lower element to turn on while the upper element remains off. In stage B, depletion of hot water activates the priority upper element and shuts off the lower element. In stage C, the hot-water draw has stopped and the upper element is satisfied, allowing the lower element to resume heating the remaining cold water. In stage D, the tank contains warm water and both elements are off.

1569

Ice on regulator

· p. 273

The illustration shows an exterior gas meter connected to a pressure regulator, a shutoff valve, and gas piping leading to the house. Ice coats the regulator and portions of the overhead piping, with icicles hanging from them. Snow covers the ground around the base of the meter assembly. The annotations warn that ice buildup can block regulator vents and potentially allow excessive gas pressure into the house, particularly when the meter is below the roof drip line.

1570

Poor meter locations

· p. 273

Four diagrams illustrate improper gas meter locations. Panel A places a meter beneath a combustible stairwell. Panel B shows a meter within three feet of a boiler, identified as an ignition source. Panel C depicts a meter and associated piping below the roof drip line, with ice hanging from the piping and regulator and snow beneath the assembly. Panel D shows a meter inside an unvented enclosure.

1571

Gas piping support

· p. 273

A building cross-section shows gas service piping passing through a foundation wall, with a vertical riser and a supported horizontal basement run supplying a boiler. The riser is secured to framing, with an annotation requiring vertical support at every floor. Horizontal piping support intervals are shown as 6, 8, or 10 feet according to pipe diameter. A separate tubing chart gives intervals of 4, 6, 8, or 10 feet for specified copper and CSST sizes. Notes state that CSST requirements vary by manufacturer and that Canadian readers should use 6-foot horizontal support spacing for all tubing.

1572

Sediment trap

· p. 273

The illustration shows a gas-fired storage water heater with hot and cold water connections, a cold water supply valve, and a draft hood beneath the vent connector. Gas piping descends beside the heater to a tee, whose horizontal branch connects to the gas valve and thermostat control assembly. A capped vertical pipe extends below the tee to form a sediment trap, shown enlarged in a circular detail. The annotation explains that this trap collects sediment to reduce the chance of clogged gas valves or burners.

1573

Gas shutoff valves

· p. 274

This cross-sectional illustration shows an exterior gas meter supplying a gas line through a foundation wall into a basement. The gas line branches down to a gas boiler and a gas water heater, with individual shutoff valves highlighted near each appliance. An annotation specifies that shutoff valves should be located as close as possible to each appliance. Both appliance connections include a tee with a capped downward pipe extension below the valve. Water supply piping and vent connections are also shown.

1574

Teflon tape at connections

· p. 274

The cross section shows an exterior gas meter supplying a basement gas water heater through piping routed beneath the floor framing and down beside the heater. A magnified inset shows threaded steel pipe connections at an elbow, with a red prohibition symbol over a tape-wrapped joint. The annotation states that white Teflon tape is not suitable for steel pipe, but yellow Teflon tape may be permitted. A separate arrow identifies pipe dope as the preferred method of sealing the pipe connections.

1574.5

FVIR (Flammable Vapor Ignition Resistant) water heater

· p. 274

The illustration shows a cutaway of a flammable vapor ignition resistant (FVIR) gas-fired storage water heater. Hot-water outlet and cold-water supply connections flank the exhaust vent at the top, and an internal dip tube extends toward the bottom of the tank. The lower cutaway exposes the burner and flame arrestor screen, with a gas valve mounted on the exterior. A sealed burner access port and thermal cutoff switch are identified near the base, where an arrow indicates incoming burner air. No defect or improper installation is depicted.

1575

Scorching

· p. 274

The illustration shows a gas-fired storage water heater with a top-mounted draft hood and vent connector, cold-water connection, and external gas supply piping. A magnified detail shows the lower burner access area with the burner cover removed, exposing the heat roll out shield and gas tubing below the thermostat control. Orange flame shapes extend outward at the burner opening, illustrating a flame rollout hazard. The annotation directs inspectors to look for scorching around the shield, gas valve, gas tubing, and exterior of the tank.

1576

Vent connector length

· p. 275

The illustration shows a gas-fired tank water heater connected to a vertical B-vent by a vent connector that rises above the heater and turns toward the wall beneath floor framing. A horizontal dimension line indicates the connector length between the heater connection and the B-vent. Annotations identify lengths under 5 feet as preferred, 5 to 10 feet as marginally acceptable, and more than 10 feet as suspect. Additional notes state a maximum horizontal run of 1.5 feet per inch of connector diameter and a horizontal distance no greater than 75% of the vertical height. Gas piping, hot and cold water connections, and a side-mounted relief valve with a discharge pipe are also shown.

1577

Poor connections

· p. 275

The illustration shows a gas water heater connected to a vertical B-vent by a metal vent connector with several elbows and joints. The connector crosses toward the wall with an uneven slope and a low point along its run. Dashed circles highlight joints to check for disconnected sections and the presence of three screws at each connection point. An annotation warns that inadequate support can cause improper slope and low points where condensation collects. Gas piping and hot- and cold-water piping are also shown at the heater.

1579

Size of vent connector

· p. 275

The illustration shows a gas water heater with a draft hood and flue collar at its top. Three detached vent connector examples compare connector diameters relative to the flue collar. A straight connector matching the collar diameter has a green check mark, while reduced- and enlarged-diameter connectors have red prohibition symbols. Annotations warn that an oversized or undersized connector can cause condensation or combustion-gas spillage. A separate note states that vent connector size should increase where appliances are manifolded.

1578

Vent clearances

· p. 275

A gas water heater is connected to a vertical B-vent by a single-walled vent connector labeled as typically 4 inches in diameter. The connector rises from the heater and turns toward the B-vent near wood framing. Cross-section details indicate a required 1-inch clearance around the B-vent and a required 6-inch clearance around the single-walled connector. The drawing also shows the heater's gas supply, hot and cold water piping, and a side-mounted relief valve with a discharge pipe extending toward the floor.

1580

Chimney/vent connections

· p. 275

The illustration shows a gas water heater and a gas furnace venting through separate vent connectors into a shared masonry chimney. The smaller water-heater vent connector enters the chimney above the larger furnace vent connector, as the annotation specifies. Both connectors rise toward the chimney from their respective appliances. The furnace is also shown with return and supply ductwork, with arrows indicating airflow.

1581

Vent connector extends too far into chimney

· p. 275

· p. 277

The side-view illustration shows an oil-fired water heater with a burner mounted near its base and an exhaust flue connected near its top. The flue runs toward the wall through two elbows, a vertical section, and a horizontal section. An annotation states that an elbow is equivalent to about 10 feet of straight flue, and a general-rule note gives a maximum flue length of 10 feet plus two elbows. Two water pipes extend above the tank, with red and blue arrows indicating outgoing hot water and incoming cold water; a shutoff valve is shown on the cold-water pipe.

Water Heaters ·Conventional Tank Type Water Heatersp. 278

1592

Exhaust flue clearances

· p. 278

The side-view illustration shows an oil-fired tank water heater with a single-wall exhaust flue extending from its upper side toward a wall. Elbows connect the lower horizontal section to a vertical rise and an upper horizontal run. A circular cross-section detail and dimension arrows illustrate clearance around the flue, with an annotation specifying 9 to 18 inches of clearance to combustible materials. The heater also has a burner near its base and two top water connections, with red and blue arrows indicating outgoing hot water and incoming cold water.

1593

Relative recovery rates

· p. 278

The illustration compares relative recovery rates for electric, gas, and oil conventional tank-type water heaters using three vertical bars. Electric has the lowest recovery rate, gas is intermediate, and oil has the highest. Each bar contains a drawing of the corresponding storage water heater, with red and blue arrows indicating hot-water outlet and cold-water inlet flow. The gas heater has a top-mounted vent and a lower gas control, while the oil heater has a burner mounted near its base. No numerical recovery rates or units are provided.

1594

BTUs per hour compared to Kilowatts

· p. 278

The illustration explains the relationship between thermal energy and heating power using water, burning matches, and a light bulb as visual symbols. At left, a burning match beneath a cube representing one pound of water illustrates that one BTU raises its temperature by 1° Fahrenheit. At right, a light bulb labeled 1 Kilowatt is equated to 3,412 BTUs per hour, represented by an array of burning matches. This is a unit-conversion diagram relevant to water-heater ratings, not a depiction of a water-heater assembly or installation defect.

1595

Gas burner cover and roll out shield

· p. 278

The illustration shows a conventional gas-fired tank water heater with a top-mounted draft hood and vent connector, hot-water outlet, gas supply pipe, and thermostat control. An enlarged detail of the lower burner access area shows the burner cover pulled away to reveal the heat roll out shield and gas tubing behind it. Dashed arrows indicate the cover's installed position over the access opening. The annotation instructs inspectors to verify that both the burner cover and heat roll out shield are present and in good condition; no specific defect is depicted.

1596

Working space around water heaters

· p. 278

The side-view illustration shows an oil-fired storage-tank water heater between enclosing walls. Dimension arrows indicate 24 inches of working clearance on either side of the equipment. Annotations call for adequate space for servicing and replacement and doors wide enough to remove the tank. The heater has top-mounted water piping, a vent connector leading toward the left wall, a side-mounted oil burner near the base, and a side valve with a discharge pipe extending downward.

1597

Water heaters in garages

· p. 278

The side-view illustration shows a fuel-fired tank water heater on a raised platform beside a vehicle in a garage. A dimension indicates that the platform is 18 inches above the garage floor. The heater has a burner assembly near its base, water piping at the top, an exhaust vent turning toward the wall, and a side-mounted valve with a discharge pipe extending downward. The annotation explains that elevation is intended to prevent gasoline vapors from being ignited by the pilot or burner.

1598

Superheated water

· p. 279

A schematic vessel contains water labeled as 300°F or more under high pressure. A rupture in its right side releases a plume of steam. The annotation explains that the pressure drop causes the superheated water to turn instantaneously into steam with explosive outward force. Large red arrows radiating away from the vessel illustrate the direction of that force.

1599

Temperature/pressure relief valve

· p. 279

The illustration shows a temperature/pressure relief valve installed near the top of an electric tank-type water heater, with a discharge pipe extending down to within 6 inches of the floor. Three simplified valve cross-sections show normal operation, relief under pressure exceeding 150 PSI, and relief under temperature exceeding 210°F. Under excess pressure, water overcomes the spring force and opens the poppet valve to the drain outlet. Under excess temperature, expanding wax in the sensor probe pushes a piston to open the valve; a manual relief lever can also open the poppet. The tank drawing shows hot and cold connections and a less-than-6-inch dimension locating the relief valve near the tank top.

1600

Gas shutoff on high temperature

· p. 279

The illustration shows a direct-vent gas storage water heater with hot and cold water connections, a vent, and an external gas supply line. An enlarged cutaway details a high-temperature automatic gas shutoff valve with a temperature probe extending into the tank near the dip tube. The annotation states that water temperatures above 210°F cause the valve to shut off the gas supply automatically, and manual resetting is required after the water cools. The detail marks a vertical distance of less than 6 inches between an upper reference line and the probe level. The main view also identifies the lower gas valve and a drip leg in the gas piping.

1601

Baffle collapsed or missing

· p. 279

A cutaway view of a gas-fired tank-type water heater shows the central flue, burner, water connections, and internal tank components. A twisted flue baffle (turbulator) has fallen down onto the burner, with a callout identifying interference with burner operation. The flue leads upward through the tank to a draft hood and vent connector. The drawing also identifies the cold-water dip tube, sacrificial anode rod, tank insulation, gas valve and piping, and temperature/pressure relief valve.

1602

Isolating and drain valves

· p. 280

The illustration shows a conventional gas-fired tank water heater with hot-water and cold-water connections at the top. An enlarged detail identifies the cold-water isolating valve and instructs the inspector to check for its presence and leakage. A second enlarged detail shows the threaded drain valve near the bottom of the tank, with instructions to check for leakage or damage. The heater also has a draft hood and vent connector, a gas supply pipe and control assembly, and a side-mounted relief valve with a discharge pipe extending toward the base. No actual leakage or damage is depicted.

1603

Multiple water heaters are installed in parallel

· p. 280

A basement cross section shows two gas-fired storage-tank water heaters connected in parallel. The blue cold-water supply rises past a main shutoff valve and branches through a common manifold to the cold inlet of each heater, with an individual valve on each branch. Red piping joins the hot outlets of both tanks into a common hot-water distribution line. Arrows indicate cold water flowing into both heaters and hot water flowing out toward the shared outlet. Gas supply connections, short vent sections, and side-mounted discharge piping are also shown, alongside the foundation wall and beneath the floor framing.

1604

Circulating hot water system

· p. 280

A basement cross section shows a gas-fired tank water heater connected to a domestic hot water recirculating system. Blue piping supplies cold water through a main shutoff valve and branches to the heater, while red piping carries hot water away from the tank. A separate return line directs water through an aquastat, recirculating pump, and check valve into the heater's cold-water supply connection. Directional arrows indicate flow through the supply and return piping. An annotation explains that the pump may run continuously or start when the aquastat senses return water below an example temperature of 110°F.

1604.5

Circulating hot water system with bypass

· p. 280

The schematic shows a gas-fired storage water heater supplying a shower and sink through red hot-water piping, with blue piping representing the cold-water supply. A circulating pump near the sink connects the hot and cold lines through a bypass, with arrows showing circulation from the hot line back into the cold line. The bypass control prevents hot and cold water from mixing when the pump is not operating. An annotation identifies thermostat or room motion-sensor control of the pump. The drawing also shows the main water shutoff, gas supply, floor framing, foundation wall, and floor slab.

Water Heaters ·High Efficiency Gas Water Heatersp. 281

1605

Power vented water heater

· p. 281

The cross section shows a gas storage water heater in a basement beside a foundation wall. A blower mounted on top of the heater discharges through an ABS or PVC exhaust vent that rises and runs horizontally through the foundation wall to the exterior. Red and blue piping identifies the hot-water outlet and cold-water supply, and a gas line connects to the lower portion of the heater. An enlarged detail shows the blower assembly, junction box, pressure switch and tubing, and a clamped rubber coupling connecting the blower discharge to the exhaust vent. Floor framing, the basement slab, and exterior soil establish the installation context; no specific defect is identified.

1606

Improper side wall vent locations

· p. 281

The illustration shows a house elevation with four sidewall vent terminations marked by red prohibition symbols to identify improper water-heater vent locations. The examples place vents beneath a window, near a gas regulator, close to grade, and low above a paved public walkway or driveway. Callouts specify separation distances from openings, the regulator, grade, and public paving. Additional annotations identify inadequate clearances from soffits, inside and outside corners, mechanical air inlets, and decks, balconies, or porches. A note cautions that the dimensions vary by area and circumstance and directs the reader to check local rules.

1607

High efficiency gas water heater

· p. 281

A cutaway depicts an insulated, high-efficiency gas storage water heater with a stainless steel combustion chamber and coiled exhaust piping surrounded by tank water. The burner is located low in the tank, with a forced draft fan, gas valve, and combustion air inlet in the compartment below. Connections include a top hot water outlet, a lower cold water inlet, a side exhaust vent, and a pressure/temperature relief valve with a downward discharge pipe. Two additional hot water side taps are identified for an optional fan/coil connection. An annotation explains that this type of heater is often connected to a coil in a forced air furnace to provide both space heating and domestic hot water.

1607.5

High efficiency gas water heater

· p. 281

· p. 282

· p. 284

· p. 286

The illustration shows a cast iron waste pipe with an enlarged bell, or hub, at one end and a spigot at the other. The exterior view identifies the barrel and beads at both ends. A separate cross section shows a spigot inserted into the bell of another pipe. Oakum fills the lower portion of the space between the pipes, with lead above it and a lead groove identified near the hub opening. No defects are depicted.

Drain, Waste And Vent Plumbing ·Drain Piping Materials and Problemsp. 287

1628

Hangers for copper pipe

· p. 287

The illustration shows copper piping beside a wood joist, with one pipe improperly supported on nails driven into the joist. A separate detail shows a steel hanger supporting copper pipe, with insulating tape at the contact area. The annotations specify brass or copper hangers as suitable supports for copper piping. They warn that nails or uninsulated steel hangers can cause localized deterioration of the pipe or hanger, and instruct that steel hangers be wrapped with insulating tape.

1629

Cross connections

· p. 287

The illustration shows cross-connection hazards at a bidet, an old-style bathtub with a low faucet, and a laundry tub. The bidet nozzle and bathtub spout are below the illustrated water levels; the indicated remedies are installing a vacuum breaker and replacing the fixture, respectively. A laundry tub with a spout below its flood-level rim is compared with a tub having a raised spout and an air gap above the rim. The annotations recommend replacing a faucet whose spout is below the rim, or adding a hose bibb vacuum breaker to a hose-threaded spout above the rim. These measures address the risk of contaminated fixture water being siphoned into the potable supply under negative supply pressure.

1630

2 ways to reduce risk of backflow into dishwasher

· p. 287

The illustration shows two ways to reduce the risk of backflow into a dishwasher connected to a kitchen sink drainage system. One enlarged cross section shows the dishwasher drain hose looped high and secured beneath the countertop with an anchoring device. The other shows a countertop-mounted air gap device with a chrome cap, a dishwasher hose connection, and a separate hose leading toward the sink trap. The main view shows the dishwasher beside a kitchen sink with a garbage disposer and trap, with solid and dashed piping indicating alternative discharge connections into the disposer or trap.

1631

Standpipe

· p. 287

· p. 289

· p. 291

· p. 292

· p. 293

· p. 294

· p. 296

· p. 297

· p. 298

· p. 299

The illustration shows a tiled shower stall with a mortar base, together with an enlarged cross section of its floor and drain assembly. Floor tile rests on a mortar bed above a liner and a sub-base sloped toward the drain at 1/4 inch per foot. The liner turns up at the perimeter and is secured to a two-piece clamping drain, with weepholes allowing water at the liner level to enter the drain. A trap below the floor connects the drain to the drain pipe, and the section also shows the shower curb, door, tile backing, and surrounding framing. An annotation advises particular inspection attention to the base and wall tiles just above it; no specific failure is depicted.

Fixtures And Faucets ·Whirlpool Bathsp. 300

1686.3

Cement board installation

· p. 300

The illustration shows cement board construction alongside its installation as a bathtub surround tile base. The enlarged board detail identifies a Portland cement core, coated glass fiber mesh on both faces wrapping around one side, a textured face, cut edges, and a smooth wrapped edge. The surround diagram shows panels on three walls with 1/8-inch spaces between boards. The lower board edges are positioned approximately 1/4 inch above the tub lip using shims or spacer strips. A printed note states that drywall compound and tape are not needed for a tile base and that adhesive will fill the gaps.

1686.6

Tile failure due to moisture

· p. 300

The illustration shows a bathtub with a three-sided tiled surround, divided by a dashed line into good and bad conditions. The good side identifies watertight grout, maintained caulking at the bathtub edge, tile tops and corners, and appropriate backing material. The bad side shows loose or debonding tiles and explains that deteriorated caulking or grout permits moisture behind the tile, damaging adhesive and backing. An additional annotation warns that moisture-exposed drywall can disintegrate and support mold growth.

1687

Whirlpool bath

· p. 300

The illustration shows a sectional view of a filled whirlpool bathtub with its pump and associated piping. Directional arrows show water being drawn through the suction cover and suction pipe into the pump, then returned through the pressure pipe to a jet in the tub wall. An air induction control is connected to the jet assembly, with an annotation explaining that opening it introduces more air bubbles into the jet discharge. A volute drain and drain line are shown beneath the circulation piping. The tub rests on an integral wooden base, and its bottom drain and overflow connect to waste piping and a trap at the right.

1688

Make sure the jets are submerged before testing

· p. 300

A cutaway view of a whirlpool bathtub shows the pump, pressure piping, wall jet, suction piping, and suction cover, along with the drain and overflow assembly. Arrows indicate circulation from the suction connection through the pump to the jet. The illustrated water level is below the jet, causing the exposed jet to spray above the water, and is marked with a red X. A dashed line marked with a green check indicates the proper testing water level, 1 to 3 inches above the jet.

1689

Bathroom outlets and switches

· p. 300

The illustration shows a bathroom with a pedestal sink, mirror, and bathtub with a showerhead and curtain. A wall-mounted electrical device is positioned between the sink and the tub/shower area. A horizontal dimension marks a minimum separation of 3 feet between the electrical device location and the bathtub/shower boundary. The annotation presents this separation as the recommended placement for bathroom outlets and switches.