Bypass loop

Heating · Distribution Systems · printed page 157 (PDF page 158)

Book index entries

with Bypass Loop Bypass Loop on Hot Water Heating System Hot Water – with Bypass Loop Hydronic Heating – with Bypass Loop

Text in the illustration

a bypass loop uses a mixing valve to direct some of the hot water coming off the boiler back into the cold water return to minimize thermal shock and condensation on the combustion side of the heat exchanger
exhaust flue
vent damper
cold water return
mixing valve
hot water
boiler
circulating pump

Generated explanation

The illustration shows a hydronic heating boiler with a bypass connection between its hot-water outlet and cold-water return. A mixing valve, highlighted by a dashed circle, directs some outgoing hot water into the return piping before it passes through the circulating pump and enters the boiler. Red and blue pipe sections and arrows indicate hot supply water and cooler return water and their flow directions. The annotation explains that this arrangement minimizes thermal shock and condensation on the combustion side of the heat exchanger. An expansion tank, exhaust flue with vent damper, relief valve with discharge piping, and a valved water-feed connection are also shown.

Components

hydronic boiler bypass loop mixing valve hot-water supply piping cold-water return piping circulating pump expansion tank exhaust flue vent damper pressure relief valve relief valve discharge pipe water-feed connection shutoff valve