Weird hot water issue

[Jarred Ellison]

Hi, I am having trouble getting hot water to my furthest bathroom. I am currently having my 2 other bathrooms redone and they had to shut off the water multiple times. I figured this messed with my water heater and it crapped out. (it was 18 years old). So I installed a new water heater and I'm getting scorching hot water in the kitchen and garage. In the problem bathroom, when both his/her sinks are running the water gets hot. If I turn one off the temp drops. In the shower it only gets luke warm. Its a Moen valve that maybe original. (House is mid 60s). Now if im in the shower and my wife flushes the toilet, it becomes scorching until the toilet is done filling and then the shower goes back to luke warm. We had zero issues before we started the bathroom remodel. They only installed new shower valves.

Is it possible to mess up on a valve install to give me these symptoms?? My first thought is there has to be cold water getting introduced somewhere, since when the toilet pulls cold water the shower gets scorching.

Sorry for the long post, I'm just beyond lost. Does anyone have any suggestions.

Thanks,
Jarred

 

[Plumber69]

If they put new valves in but not the cartridges yet, that may cause this

 

[Sponsor]

 

[Jadnashua]

Some models of valves when they fail can create a cross-over between the hot and cold, thus giving warm. Water will flow the path of least resistance, so what you get in one part of the house, may be different in others just because of the resistance in the flow.

So, it may just be you need a new cartridge or two in one of your single-handle valves.

If the shower valve was built after the anti-scald tech was introduced, and it doesn't work, the spool-valve may be stuck, and either needs to be freed up, or a new one installed. This is designed to help adjust the flow so a loss in cold water pressure will cause a loss in the hot line, too, keeping the balance the same, and thus, the outlet temperature close to the same.

 

[Jarred Ellison]

If they put new valves in but not the cartridges yet, that may cause this

I posted this on other forums and got this same response. It never dawned on me that they didn't install the cartridge yet. I hope this is my issue. Sucks I tossed an 18 year old heater over this. Thanks for the reply.

 

[Jarred Ellison]

Some models of valves when they fail can create a cross-over between the hot and cold, thus giving warm. Water will flow the path of least resistance, so what you get in one part of the house, may be different in others just because of the resistance in the flow.

So, it may just be you need a new cartridge or two in one of your single-handle valves.

If the shower valve was built after the anti-scald tech was introduced, and it doesn't work, the spool-valve may be stuck, and either needs to be freed up, or a new one installed. This is designed to help adjust the flow so a loss in cold water pressure will cause a loss in the hot line, too, keeping the balance the same, and thus, the outlet temperature close to the same.

Thanks ill start replacing after they finish the installs. Thank you