No cold water in sink after installing Shower valve

[chrisjax]

So I'm really stumped on this one. (But have no plumbing background either) I have a 10 year old house with PEX piping and I recently replaced a shower handle. There were no shut off valves to this shower ever installed, so I added one to both the hot & cold lines, then installed the new handle and valve. Everything is running perfectly in the shower except I have no cold water going to the dual sinks in the same bathroom. Cold water if flowing fine everywhere else in the house.

Here's another twist.....if I flush the toilet in that bathroom and wait a second, then cold water comes flying out of the sinks! Then immediately stops once the toilet tank has finished filling back up. I removed the shut off valves I installed to the shower to see if they were the culprit, but still same problem. I checked the piping and didn't see any leaks or where it might of been bent anywhere. So my only guess is there's a pressure issue, not sure where or how though.

Any thoughts are appreciated!

 

[Twowaxhack]

You need a priest not a plumber.

 

[TomFOhio]

If everything worked fine before you replaced the shower valve then I would that could be the problem. You could of shut off the valves to the shower to see if that made any difference.

 

[Twowaxhack]

If everything worked fine before you replaced the shower valve then I would that could be the problem. You could of shut off the valves to the shower to see if that made any difference.

How would that cause the lavatories to start flowing when the toilet is flushed ?

 

[TomFOhio]

I don't know but he has to try something.