# crossover problem



## joefromcal (Apr 8, 2008)

Hello. I'm having a problem with hot water coming out of my cold water taps at times (even ones that have two handles).

From what I've read, single handle faucets and valves that have become defective can cause this. Sometimes, once it starts, the hot water doesn't finally cool down after I let it run for a while. 

Other times, it'll cool down after a while. I'm not talking warm but hot water. I have a hot water heater and two showers with single handle valves (one is a moen) and I have a single handle Kohler forte faucet with one of those heads you can pull away from the unit. 

Since my Moen shower valve was leaking anyways I had my plumber replace the cartridge and now it no longer leaks.

He felt inside the pipe where the cartridge goes into before he put it in to see if he could feel any grooves (which would allow water to pass he said) but said it felt ok. The new valve he put in was plastic. However, my crossover troubles still continue.

I just got done turning on the kohler kitchen faucet and the water was coming out the tap was hot so i reached under the sink and felt the hot water line but it was cool, and the cold water line was hot.

So it seems to me that the hot water wasn't coming from the hot water side of the kohler unit but from the cold water line itself. This leads me to believe that the odds are against there being a problem with the kohler faucet. However, that still leaves one other shower single handle valve (which I took a photo of and my local plumber supply store said was plastic and which they claim wouldn't be a cause of crossover since it was plastic). Is there any other trouble shooting anyone can recommend or any way that I can check the other shower valve (which is enclosed so i can't feel the hot and cold water lines. 


Also, I felt both lines feeding into my hot water heater and while the hot water line out was warm the cold water line in was also warm.

Is it possible that the hot water may be coming back out of the hot water heater and going into my cold water line? Also, I have a clothes washer with a hot and cold line but it has two valves, one for the hot water and one for the cold water so it didn't seem possible to me that crossover could be happening there?

Any suggestions would be much appreciated. Thank you.


----------



## plumberinlaw (Feb 22, 2010)

It's probably the moen, it usually is


----------



## joefromcal (Apr 8, 2008)

plumberinlaw, that's what we thought but after my plumber replaced the cartridge the problem still continued. Thanks, Joe


----------



## plumberinlaw (Feb 22, 2010)

turn off the valves to your washing machine see if it stops


----------



## TheEplumber (Jul 20, 2010)

Turn off the CW supply to the water heater. Now you should not get any water in the hot position delivered to any fixture. If you do, then the 2nd shower or kitchen or laundry has your crossover. You can eliminate the kit faucet and laundry by turning off the supply valves to them


----------



## joefromcal (Apr 8, 2008)

plumber in law, thanks for the info. I did that and the problem continued. e plumber, I ended up closing all the single handle faucets except for one which was stuck and the problem continued. 

And I closed off the clothes washer too. So I figured it was the hot water heater letting water go backwards into the cold water line or my other shower or one faucet that I couldnt close since the line was stuck. 

I had a plumber come by and he says it's the handle to the other shower that's causing the problem

. I don't know how he determined that since my wife says he didn't turn off the water supply. Possibly he checked the water heater and verified it was ok and the other faucet also must've checked out. What I'd like to know is if he's sure. He didn't give me any more info that that but I wonder if the cartridge may just need to be replaced.

He says the entire housing needs to be replaced but again I don't know how he'd know that if he didn't take out the cartridge and check the inside. When my other plumber put a new cartridge into my first shower he felt around inside to make sure it had no cracks or gouged areas.

I don't mind paying to have the whole unit replaced if it's really that (big bucks) but If it's only the cartridge I don't want to have to have to replace something that doesnt need replacing. Thank you both for your help and suggestions. Joe


----------



## joefromcal (Apr 8, 2008)

*crossover trouble.*

Well, after doing a little research, I went and bought a water pressure gauge with a lazy hand. I installed it on the outside water spigot to see what the pressure was there. It was 122 which is a lot higher than 80 so I guess I need a need regulator. I'll leave it there for 24 hours to see where the lazy hand goes. Then I'll screw it into my hot water heater spigot to check the pressure there. What I'd like someone's opinion on is if my pressure is too high from the outide or if I'm having thermal expansion (from the water heater) could that cause backflow into my cold water line from my water heater and be responsible for my crossover problem? Thank you.


----------



## TheEplumber (Jul 20, 2010)

When you close the cold water supply valve at the water heater, do you get any water pressure out the hot side of any of your fixtures?


----------



## Alan (Apr 12, 2006)

TheEplumber said:


> When you close the cold water supply valve at the water heater, do you get any water pressure out the hot side of any of your fixtures?


You skipped over this guy's post once ^^^^ 

Please try what he is suggesting.

Thermal expansion is not going to cause hot water to backfeed into the cold during use. 


What about a recirculating system on the hot water heater? Do you have one of those?


----------



## joefromcal (Apr 8, 2008)

No, I did see what eplumber suggested. Will be trying that soon. Just wanted to check my pressure regulator as well while I was at it and when I got the results I did I was surprised. Looks like I have two issues then... Thanks for the info. Joe


----------



## oh'mike (Sep 18, 2009)

TheEplumber said:


> Turn off the CW supply to the water heater. Now you should not get any water in the hot position delivered to any fixture. If you do, then the 2nd shower or kitchen or laundry has your crossover. You can eliminate the kit faucet and laundry by turning off the supply valves to them



Read this one again---Your answer is here---


----------



## joefromcal (Apr 8, 2008)

*crossover issue*

OH'mike and others, Finally was able to spend some more time working on my crossover issue. I did open up that shower valve and luckily it had a turnoff (service check stops that you could screw in) so i was able to turn off both the hot and cold water supply to my shower. My crossover problem continued. So I was able to turn off every faucet and plumbing fixture one by one (except for another shower fixture but we did put in a new cartridge) and still my crossover issue continued. I had a plumber check for me and he said he didn't see I had a recirc system unless it's up in the attic and he couldn't see it. I live in southern california and as you know it can get quite hot here. The plumber said my attic was very hot and he thought it might be my pipes getting hot since they weren't insulated. He said to turn on my attic fan to see if that made a difference but it didn't. So what I decided to do was put my hot water heater on vacation mode. I waited about 2 days until all the hot water was used up (its 75 gallons). At this point, I went to the shower and turned on the hot water and it had hot water for a few seconds and then the water got cool and stayed cool. So I went to the kitchen and turned on the cold water and guess what? It came out cool for a few seconds and then got very warm and stayed that way. Since I know the hot water heater couldn't be the source of the heat then the only thing left is that my pipes in the attic must be getting very hot. Just wanted to send you an fyi. Appreciate your input and help with this.


----------



## oh'mike (Sep 18, 2009)

That's something us northerners would not have considered----

An attic water heater----


----------



## joefromcal (Apr 8, 2008)

*attic heater*

Yeah, I just wanted to make sure before I spent any more money. Needless to say, I'm very surprised that a hot attic could cause my pipes to get so hot. Live and learn. Now I have to see about insulating the pipes. thanksss again, Joe


----------



## torerodactyl (May 15, 2018)

In the original post was written *"i reached under the sink and felt the hot water line but it was cool, and the cold water line was hot."* Doesn't that imply the pipes to the sink were connected wrong? Couldn't that explain all the symptoms?

I know several years have gone by, but it appears the problem was never solved. (Or, if solved, that wasn't reported here.)

I found this thread by googling 'water hot cold crossover sink "clothes washer" OR dishwasher'. I'm trying to learn whether it's possible for the source of crossover of cold water into the hot water pipe (symptom: cool water from the kitchen sink faucet when the control lever is set to Hot) to be in a dishwasher or clothes washer (located in the kitchen).


----------

