mikeconte
New Member
hot from cold -- fixed!
Thought i would report back on the fix. Thanks everyone for the advice.
Basically, I isolated the problem to a backfeed from the hot water heater inlet back into the cold water lines. I could tell this was happening because if i shut off the cold inlet to the HW heater after the hot water was warmed up, the problem went away. So it was not crossing over at a faucet.
I had installed a check valve on the water inlet, but it was the swing type and was not working reliably. I replaced it with a plunger type, which has rubber seal and a spring-loaded plunger, and that solved the problem.
My best guess is that the problem existed from the get go, tho it was perhaps less noticable with the smaller 5g expansion tank. In any case, once the tank bladder failed the problem wasn't evident because there was no hot water pushed out of the hot water tank when the cold was run (the tank is on the hot side of the HW heater).
In any case, the high pressure eventually caused the failure of the TPS valve. I replaced both the tank and the valve, and the problem came back. As above, a check valve on the cold water feed to the heater solved it.
Thanks again - this forum is a great resource.
Mike
Thought i would report back on the fix. Thanks everyone for the advice.
Basically, I isolated the problem to a backfeed from the hot water heater inlet back into the cold water lines. I could tell this was happening because if i shut off the cold inlet to the HW heater after the hot water was warmed up, the problem went away. So it was not crossing over at a faucet.
I had installed a check valve on the water inlet, but it was the swing type and was not working reliably. I replaced it with a plunger type, which has rubber seal and a spring-loaded plunger, and that solved the problem.
My best guess is that the problem existed from the get go, tho it was perhaps less noticable with the smaller 5g expansion tank. In any case, once the tank bladder failed the problem wasn't evident because there was no hot water pushed out of the hot water tank when the cold was run (the tank is on the hot side of the HW heater).
In any case, the high pressure eventually caused the failure of the TPS valve. I replaced both the tank and the valve, and the problem came back. As above, a check valve on the cold water feed to the heater solved it.
Thanks again - this forum is a great resource.
Mike
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