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Author:
crossover (CA)
Hi everyone, I need some serious help.
Slab home. One 75gal gas water heater. Recirc line, pump on a timer. Works great. Get hot water instantly.
Problem: When recirc pump is running, unable to get really cold water from faucets, and often, it's very warm.
In addition, I work in my garage a bunch and I've noticed that the gas water heater will fire a couple times an hour when the pump is on, and only once every couple hours when it's off. Gas bill is ~$150 while my neighbors' are closer to half that.
Solutions:
I have checked my water meter and I don't have a leak when water is not being called for.
I had the check valve between water heater and recirc pump replaced already, did not make much of a difference.
To test for a crossover, I turned off the cold line, unplugged the recirc pump and then turned on a hot faucet. Flowed full force for 45 seconds then went down to about 10% flow and stayed hot at 10% flow indefinitely.
Need some help on how to figure out where the crossover is. Appreciate your help!
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Author:
bernabeu (SC)
? shower ?
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
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Author:
hj (AZ)
somewhere, under the floor, your hot and cold lines are close together or touching, so when the pump keeps the hot water line hot, it is also heating the cold pipe. The lines under the floor are not insulated so the water as it circulates is constantly being cooled off so the heater HAS to turn on and off to keep the tank hot. It is a byproduct of the convenience of "instant hot water".
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Author:
srloren (CA)
A recirc line by its very nature tends to cool down the hot water causing the heater to cycle more often. Recirc systems can cause damage to copper lines over time, most noticably near the pump. You should use long turn elbows when installing these systems to cut down on friction loss and wear and tear on your copper water lines.
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