Water heater, plumbing or faucet?
Not exactly “Energy, Heating and Insulation” but here goes…
Kitchen sink is about 18′ (of plumbing) from the water heater, 3/4″ PEX and copper teed off to 1/2″. American Standard single handle faucet at the sink. Sometimes you turn on full hot and it heats up fine, gets plenty hot. Mix with cold, everything seems normal, then turn back to full hot and it won’t heat again, almost like there’s no hot coming out of the heater. But you can go down and feel the copper line coming out the top of the tank, and it’s plenty hot. I’ve pulled the cartridge out of the faucet and there’s nothing plugging hot side, and the cartridge design is a perfect no-brainer. Since the plumbing goes through conditioned space all the way from heater to faucet, there’s no insulation on it, but it still doesn’t seem like it would lose all its heat in that short a distance from Point A to B. House is on a well, so the pressure tank acts as the expansion tank, right? WTF? What am I missing? Aliens stealing my hot water?
Thanks in advance for any helpful comments. Thanks for whatever wise-axx comments surface, too. 🙂
Bob
Replies
Sounds like the faucet. What brand?
Also, is there a tub nearby? Sometimes a single-handle tub faucet can malfunction so that it "bypasses" when turned off.
American Standard. Not a real expensive one, but $100 kitchen faucet.
No tub faucets on that end of the house. All tub faucets in a completely different direction.
In our house we have cheap fawcets. I'm not sure of this but i think they don't mix well. What i mean is that if you don't turn them on full blast they don't mix well.
If the mixing ball ? and socket it goes into was desinged well it would mix well even when you turned it on part way. Now I'm not sure of this but I think that is one of the reasons why the high end fawcets cost so much.
The next time I'm in some else's house and I spot an expensive one I'm going to play with it and see. If it turns out to be the case i will spring for high end single lever fawcets. Otherwise I was thinking of just going back to two lever fawcets. That way I can adjust it however I want.
OK do a little test.
Go through the same steps as you just stated, but when you go to turn on the full hot go under the sink & turn off the cold angle stop.
One of two things should happen, either the water will stop all together, or the water comming out of the hot angle stop will be cold.
If the water stops all together, then your faucet has some serious problems.
If the water comming from the hot side is cold, then gets hot afer a bit then your faucet is probably forcing cold water down the hot side. That is usually caused by a differential in pressures between the hot & cold waters which can happen on pressure tank systems from a restrictor of some sort on the line that feeds the water heater.
Do you have a recirc on this system by chance? That can be another source for a problem like this.
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
Did the "shut off the cold at the stop valve" test. (Sounds like Maxwell Smart - Agent 86 - "ah, the old "Bomb in the Snack Truck Trick...")
Water continued to flow from only the hot line, but was lukewarm at best. Didn't feel like running the well dry to find out how long it would do that, but it stayed lukewarm for a while.
Restrictions in line that feeds the water heater? From the pressure tank, cold line goes past a pressure gauge, through a 1/4 turn shut-off ball valve, then to acid neutralizes mineral tank (calcite and Corrosex). Coming out of there it goes back over the top of the water heater where it tees a) 3/4" into the heater and b) 3/4" off to feed the rest of the cold supply lines. 3/4" out of the heater then parallels the cold to the kitchen faucet. Cold and Hot both tee off those lines - reduced to 1/2" - to feed clothes washer (and cold tees off that line to feed outside sillcock) and then over closer to the offending faucet hot tees off - reduced to 3/8"- to feed dish washer and cold tees off - greatly reduced - to feed ice maker in fridge.
There's no (intentional) recirc anywhere. I like the way you're thinking about pressure differential causing cold pushback into the hot line though. Don't know why that couldn't occur with this type of mixer cartridge setup in the faucet, just can't quite get my head around where the pressure diff could be originating. Any further thoughts? Short of buying pressure valves and finding somewhere to install then in these lines to compare, got any other practical tests in mind?
Thanks.
Nothing in your description catches my eye for a restriction, sounds like a normal piping set up.
If this happened at every faucet it would be a classic case of broken dip tube in the water heater, but since it's ony this faucet something is making it backfeed down the hot.
I looked at Speekman's website & Chronomite's to try & find the 3/8" compression check valves that I have used in the past, but no luck.
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
How would I check the dip tube? Does it come out the top if I disconnect the lines? And I assume it would be the cold tube broken at the top leaking cold directly into the hot (short) tube, right?
Thanks.
Correct, the "dip tube" is on the cold ( inlet) side of the water heater.
Usually made of plastic & slightly flanged on one end.
If the water heater didn't come with nipples sticking out of it the dip tube is sitting at the bottom of the female threads.
On models that have a nipple sticking out the dip tube is usually set in that nipple.
Some lift out without any effort & some seem like they are fused to the nipple or bung.
Don't really have any tricks to offer for that, but if it's fused 7 out of 10 times it will break when removing.
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
Thanks, I'll give it a try. Appreciate the input.
What's the age of the water heater? If made roughly 1978-85 then it likely has a plastic dip tube that fails in 5-10 years in chlorinated water.
If your view never changes you're following the wrong leader
Installed about a year and a half ago. No chlorine, we're on a well.
If, while running hot only, you closed off the cold shutoff and the water stayed warm, you've got another valve bridging the hot & cold pipes. Your comment that the pipe coming out of the water heater is plenty hot confirms this to me.Shut valves below the other single-level faucets until you identify the leaker.
I'll try it, thanks.
He should be able to find it by just feeling the valve or supply line..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Dip tube can be damaged during installation.
If your view never changes you're following the wrong leader
(Or, the dip tube can be missing entirely, or in the wrong hole.)
If your view never changes you're following the wrong leader