[Mthrboard]

My wife and I just bought a brand new house in February, a split level in a new development with an unfinished basement. My kitchen is directly above the utility room, where the water main enters my house and the water heater, furnace, and washer/dryer live. Anyway, ever since the day we moved in, I've noticed that the cold water in my kitchen faucet runs full hot for a few seconds before going to cold. This happens whether the faucet is on full cold or anywhere else on the cold side. It's a single lever Kohler faucet. I'm pretty sure it has something to do with the water heater itself, since the cold water in pipe to the heater is too hot to touch for a good 3' back from the heater. Also, when the cold runs hot, and I touch the cold water pipe below the sink, that feels hot as well. After 3-5 seconds of hot water, it goes to cold, and stays cold until you turn the faucet off. But as soon as you turn it on again, it does the same thing. There's some sort of Honeywell temperature control valve thing hooked up to both the cold water in and hot water out ports on the water heater. Could that possibly be leaking? Or could my water heater itself be flowing back through the cold input? My water heater is a 100 gallon lifetime plastic Richmond heater, if that makes any difference. None of the other fixtures (outdoor spigot that hooks in between the water main and the water heater, bathroom sink, toilet) run hot at all. It wouldn't really be a big deal to me, but I hate letting all that hot water run down the drain whenever I want a cool glass of water. Is there anything I can do to fix this? Thanks in advance for any help.

 

[LawnGuyLandSparky]

Here's what I think is happening...

When the cold supply runs past the water heater, it "T's" into the cold input, and also continues on towards your sink. When the water is static and not moving, the heated water from the water heater is conducting onto and around the cold supply, warming it up. The longer the water remains static and motionless, the more this heat is conducted into the cold. When you first turn on the cold faucet, tha "plug" of heated cold water has to go somewhere...

 

[Thurman]

Look under you kitchen sink again, look for a connection between the cold and hot water lines. The "Honeywell" thing on your water heater could be a Hot Water Re-circulator that allows hot water to flow through the hot water lines, returning via the cold water lines to the water heater tank. This is to keep the hot water lines warm or near hot during timed cycles. A lot of houses have the water heater and kitchen faucet(s) far apart and this system will keep warm water at the hot water side of the faucet most of the time. My 2 cents worth, David

 

[Mthrboard]

Here's what I think is happening...

When the cold supply runs past the water heater, it "T's" into the cold input, and also continues on towards your sink. When the water is static and not moving, the heated water from the water heater is conducting onto and around the cold supply, warming it up. The longer the water remains static and motionless, the more this heat is conducted into the cold. When you first turn on the cold faucet, tha "plug" of heated cold water has to go somewhere...

That would make sense to me if it happened only after I didn't use the faucet for a while, but it happens every single time I use the faucet, whether it's 10 seconds later or 10 hours later. As far as the temperature valve, it doesn't appear to be a recirculation valve. The kitchen sink hot water is hot immediately, but the bathroom, on the other side of the house, takes up to 20 seconds to get hot. I think it's actually something like a tempering valve. When I turn it, all it does is change the temperature of the hot water *on the hot side only*. The hot water from the cold valve always stays the same. I'm using an instant read thermometer to check, and the cold hot stays within a degree of the same, while the hot side varies by up to 15 degrees based on where I turn that valve. I went to Menards yesterday, and someone in the plumbing department suggested that I might need an expansion tank, but said that on a new house, the plumber would've installed one if I needed one. It's not a problem to install one if I need to, I did a bit of plumbing at my old house. I just don't want to do any unnecessary things. Thanks for the suggestions so far.

 

[caramelshake]

I've been using the two-handle faucet, try it out.

 

[plumber Jim]

That would make sense to me if it happened only after I didn't use the faucet for a while, but it happens every single time I use the faucet, whether it's 10 seconds later or 10 hours later. As far as the temperature valve, it doesn't appear to be a recirculation valve. The kitchen sink hot water is hot immediately, but the bathroom, on the other side of the house, takes up to 20 seconds to get hot. I think it's actually something like a tempering valve. When I turn it, all it does is change the temperature of the hot water *on the hot side only*. The hot water from the cold valve always stays the same. I'm using an instant read thermometer to check, and the cold hot stays within a degree of the same, while the hot side varies by up to 15 degrees based on where I turn that valve. I went to Menards yesterday, and someone in the plumbing department suggested that I might need an expansion tank, but said that on a new house, the plumber would've installed one if I needed one. It's not a problem to install one if I need to, I did a bit of plumbing at my old house. I just don't want to do any unnecessary things. Thanks for the suggestions so far.

How about a picture of the honeywell valve you speak of?

 

[Daniel Holzman]

I have a hot water tank that heats water by circulating warm water from the boiler through a coil in the tank (indirect hot water). The makeup cold water comes off the cold water in line. However, there is a backflow preventer on the cold water in line to prevent hot water from the tank circulating up through the cold water line. Perhaps your system does not have a backflow preventer, and if you installed one, it might do the job of preventing hot water from flowing up through the cold water line.

 

[Thurman]

When water heaters heat cold water and the water becomes warmer, by nature it expands, so the amount of water within a water heater can't go anywhere and pressure builds up. Sometimes, but not always, this hot water will override the incoming water pressure just enough for the hot water to back up into the cold water piping. Depending on how your plumbing system is set up, and if this is the case in your situation, you could be getting this hot water that has expanded back into your cold water piping. It will be a small amount, but can be noticeable when opening a cold water tap. Thanks, David

 

[buddy builder]

thurman's answer seems most simple yet probably hit the nail on the head. if you can loop an extra 10 to 15 feet of line from the water heater to your sink. this will take up the "short" run to your sink. any heated water in the line should be flooded by cold water now and shouldn't be noticable. buddy builder