No hot water after installing Delta valve - Pics included

[KristenJensen]

Hello everyone. I’ll try to make this as succinct as possible.

Problem: After plumbing repairs, I have cold water coming from both the hot and cold fixtures (sink in kitchen and shower in bath). I was using hot water just fine until repairs were completed.

Events leading up to: I needed plumbers to install 2 universal rough in’s with cartridges in showers. I didn’t actually have issues with my plumbing at that time.

Plumbers shut off and disconnected/decoupled the water line from the street (city side) to allow complete depressuring since water was still coming out of cut water lines in my home. They also had the water heater lever turned off and opened the faucet in the bathroom to depressure system. They installed 2 new mixing valves for 2 showers. One of the mixing valves was only “capped” with the 2 plugs (I think they use them to check the system for leaks).

The water heater is warm, and the hose leaving the top of the water heater is hot. I can feel the hot water line about 4 feet from the water heater and it is a little warm, but not hot with nothing running. When I turn the bath on hot, the pipe becomes hot where I circled the picture, but only a few feet in then it becomes cold again. (I have the wall opened up to studs). Last clue, there are short 1 second bursts of warm water from the bath when I turn the handle from cold to hot.

Plumbers are saying it’s probably a slab leak, but I think that’s a convenient cop out. I’m thinking that all the cut/open pipes (hot and cold inside the house and main at the street) caused some kind of mixing problem. I drained the water heater about 3 months ago. I included a picture of the entire wall illustrating both rough in valves and where the water lines enter the baths.

How to I troubleshoot, and how do I fix? Thank you all for the answers!

 

[Plumber69]

If you don't have the cartridges installed in the rough in you will have a cross connection. Put them in

 

[Sponsor]

 

[KristenJensen]

Plumber69. Thank you. You were 100% correct. The 2 plumbers had said they had done it like that several times without issue. Also, there weren't 2 white plastic plugs inside like I thought. It was just an empty brass housing that allowed the hot/cold water to mix. They also said that the hot water was being diverted to the hose outside (if that helps anyone else troubleshoot int the future). Thanks.

 

[Plumber69]

Plumber69. Thank you. You were 100% correct. The 2 plumbers had said they had done it like that several times without issue. Also, there weren't 2 white plastic plugs inside like I thought. It was just an empty brass housing that allowed the hot/cold water to mix. They also said that the hot water was being diverted to the hose outside (if that helps anyone else troubleshoot int the future). Thanks.

Your plumbers are just still learning. I made that mistake once when I first started plumbing

 

[CalyerBK]

Just posting here since this thread helped me figure out a problem.

Yesterday I had a Delta universal valve body installed. The plumber simply put the cap on, which is what the Delta instructions tell you to do. Then I had no hot water in the house -- every hot water faucet, no matter which side of the shower it was on, ran slightly warm to cold. But the water heater was working and water coming out of the heater drain valve was hot.

So, after reading this thread, I went ahead and installed the Delta shower body cartridge, which luckily I had bought ahead of time. I installed the cartridge (but not the trim, because i still have a wall to install and don't want to damage it). Now everything works fine. I guess without the cartridge, the cold crossed over to the hot.

 

[Tuttles Revenge]

This is the reason we only install shower valves with integrated shut off valves. We leave one valve off during rough in to prevent cross over.

 

[Jadnashua]

Anyone that has a good handle on plumbing should know that a Delta rough-in valve that does not have the cartridge installed, needs the special plug installed to prevent cross-over.

The cap is there to test the plumbing for leaks, but if you want to use the rest before you install the cartridge, it will cross-over. Which faucets will have a problem just depends, as water will take the path of least resistance.