Single handle tub faucet, no cold when hot water shut off

[Patrick Swindle]

We have a pinhole leak in our hot water line that we're getting fixed very soon, so we've shut off the hot water to the house, but in so doing, the cold water doesn't work in our tubs/showers, both with a single-handle faucet. The cold water works fine at all of the other faucets and the clothes washer. Is this how it's supposed to work?

 

[Terry]

You have a pressure balanced valve on the showers. When there is no incoming pressure on one side, it shuts down the opposite side. You won't get water from those valves until you can have balanced pressure to both sides.

 

[Sponsor]

 

[Patrick Swindle]

Wow...thank you. I didn't even know that was a thing.

 

[Jadnashua]

That valve is what prevents you getting scalded if say someone flushes a toilet and that lowers the cold water pressure...the valve slides to also partially shut down some hot so that the temperature remains nearly constant. Federal guidelines require some sort of anti-scald tech in shower valves and was implemented over 20-years ago.