We just had a pressure balanced tub/shower faucet installed in our bathroom, and something is wrong, but I'm not sure what. When testing it, we turned off the hot water going into the bathroom, and now no cold water comes out of the tub/shower either. So my biggest question is, is that normal? Do Pressure Balanced systmes shut off the cold water too when the hot water is shut off?
The big problem we are having is that the pressure in the tub/shower is very low, especially for the cold water. In the sink next to the tub, hot water comes out of the cold water tap, but if you run it for a while, it turns cold. I suspect these problems are all related.
If you have no pressure on either side of the valve, you will get this same reaction. They work just like their name implies ,"pressure balancing".. The mechanism is just a plunger that is balanced ( kept centered in the valve body) by equal hot and cold water pressure. When one side experiences a pressure drop the higher pressure moves the plunger to limit the water flow on the opposite side, thus preventing a surge of hot or cold water. I had a similiar problem once with hot/cold and our plumber said that it is something he was seeing fairly often with these valves, This was a few years back when they were fairly new, and I haven't had any problems like this recently. He did not have a solution, and it was not a problem the customer complained about.