The original problem I had was that I turned on the cold water in the bathroom and it would come out hot. After experimenting I discovered that the water in the bathroom would be warm whenever I had the backyard water turned on. I also felt the water pipes from the water heater and discovered that the cold inlet was hot. It seems that the hot water is being siphoned out of the cold inlet to the water heater. The backyard water does not seem hot, by the way. I am not too familiar with plumbing, is this a plumbing problem or is the water heater malfunctioning? Thanks in advance for your comments.
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. It seems that the hot water is being siphoned out of the cold inlet to the water heater
Seems you just answered it . Water hooked up wrong to hot water heater . Has it been replaced lately? Ive never seen this problem but Ive heard about it . Normally the cold water has a shut off . Lossen the cock on the heater and see it indeed you are turning it off and then hot and cold will be written on the top of the heater to double check it.
Tim
Edited 10/9/2005 4:19 pm ET by Mooney
Probably a bad single-handle faucet somewhere. It's letting water circulate from the hot side to the cold side when turned off.
Another possibility is a bad/missing "heat trap" at the inlet to the water heater. But if this were the problem the cold water anywhere in the house would run cool, then warm, then cold. If it's warm instantly it's the single-handle faucet at the sink or the adjacent shower.
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quick thoughts - vacuum breaker/anti-siphon at the water heater? water heater running too long -overheat problem/bad thermostat - some kind of pressure problem/backfeed issue?
Keep in mind that the hot/cold water system is a closed system, and the pressure is the same everywhere except when the water is running. When the water is running, pressure differentials will occur due to the resistance of the pipe.Also, water is incompressible, so you can't put water in at one point unless water comes out at another point or vice-versa. For this reason, hot water can't be "siphoned" backwards out of the water heater into the cold water pipe unless there is a connection elsewhere between hot and cold water pipes.You can create a connection between hot and cold if you do something like plug the spout of a faucet and turn on both hot and cold. But most people don't do this (except, perhaps, if they put a hose on a laundry tub faucet and then turn off the nozzle at the other end of the hose). The other way to create the connection is a defective single-handle faucet, where water can flow between hot and cold when the faucet is turned off.
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Thanks Dan,I thought I understand the pressure differential issue, but if there is a pressure differential at the inlet of the water heater wouldn't that not allow the hot water to siphon out of the cold inlet regardless if it is a mixining valve.
Hot water can't siphon out of the cold inlet unless water can get into the heater though the hot "outlet". That can only happen if there is a connection between hot and cold somewhere downstream.You can get CONVECTION through the cold inlet, causing the pipe to get warm for several feet. This is what the "heat trap" at the inlet is supposed to prevent. But convection will only warm up a few feet of pipe near the water heater, and you'll barely notice that at a distant faucet.
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i was going with the outside water running and "pulling" some of the hot from the heater back into the supply (????) - like I said - quick thoughts (not always good thoughts - just quick)
Do any of your toilets have tempering valves on them - a mixing valve to warm the water coming into the tank so it doesn't sweat? I've seen this cause a similar problem with hot water coming out the cold water side of faucets if the tempering valve goes bad.
I have no tempering valves near or around the toilets, unless it is in the wall and I don't know of it.