Primary and secondary loops on boiler

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Primary and Secondary Loops Primary and Secondary Loops on Boiler

Text in the illustration

short primary loop is close to the boiler with its own pump
secondary loops are fed from and return to primary loop
mixing valves are used for domestic hot water and radiant loops where boiler water is too hot
domestic cold water plumbing
to 3 heating zones
tempering valve
domestic hot water
domestic cold water
secondary loop
from 3 heating zones
primary loop
secondary loop pipes <12" apart at primary loop
boiler
indirect water heater
simplified for clarity

Generated explanation

This schematic shows a boiler with a short, pumped primary loop supplying secondary circuits for three heating zones and an indirect water heater. Red supply pipes, blue return pipes, and arrows indicate water flow through the circuits. Secondary supply and return connections are identified as less than 12 inches apart at the primary loop. The indirect water heater has separate domestic cold-water and hot-water connections, with a tempering valve connecting the cold supply to the hot outlet. An expansion tank, circulators, valves, and boiler vent are also shown.

Components

boiler primary loop piping secondary loop piping circulator pumps heating zone supply and return piping closely spaced tees expansion tank indirect water heater tempering valve domestic cold-water piping domestic hot-water piping boiler vent

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