We're in the process of remodeling a bathroom and today adding the plumbing (shower faucet and head) today. We turned off the water and ran all the plumbing, installed the faucet (it's one of the one handled faucets that you can adjust the water temp with), turned on the water after all that was done. Weird things happening with all the water in the house:

1. Hot water in all faucets is now scalding hot, at first and the mediocre when the hot water is selected.
2. The new shower copper pipes eventually both get hot.
3. The piping going to and coming out of the hot water tank are both hot/warm.

Is this problem because of improper installation of the faucet? Or, could this be the hot water tank (it's about 20 years old). Just weird that if it is the hot water tank, why it messed up on the day we did this work. The tank is pretty old, so I guess anything is possible.

Thank you for any suggestions!:confused:

It's not the hot water tank. The cold feed to it gets warm by convection, so that's normal.
What I suppect is a cross connection, most likely done when you repiped the bathroom. This will be solved by going back and double checking every connection. Good luck, Tom

Tom, thanks for your reply! OK, so here's the deal (I just found out this morning). The guy that put in the faucet, didn't install the cartridge that goes inside the plumbing housing for the faucet. I'm suspecting that this is what regulates the water temp. Is it possible that without this cartridge, it's somehow back flushing hot water into the cold and affecting the whole house? We're putting the cartridge in now, and will probably have an answer in a few hours... just want to make sure that if anyone is having the problem later can look to this website and find their answer. I'm pretty sure some people wouldn't turn the water back on without having completed the installation, though... lol. Thanks!

Sounds like you found your cross connection. Yep it can back feed.

Hi Again!
Yep, all is right with the house water temp again. Amazing what a mess one small part missing in an installation project can create... ha ha NOTE TO OTHERS: READ THE INSTALLATION DIRECTIONS!!