In 1950 house which uses city water supply and has ½ inch copper pipe. The Glacier Bay tub/shower faucet seems to have four modes. 1. Works perfectly fine. 2. Has no cold water flow at all and water comes out scalding hot. 3. Has pretty much no water flow at all. 4. During a shower or during filling the bath, the water pressure suddenly changes from full water pressure to no cold water pressure and back again (can sound like a machine gun or may change pressures at a slower rate, changing between cold off and on every few seconds). This happens with nothing else in the house using water--no running toilet, nothing.
This faucet has a single rotating handle that rotates one half revolution counterclockwise to go from off to cold only to warm to hot. No control over water pressure. The diverter to the shower is on the tub spout. I removed the faucet cartridge completely and even took it apart somewhat and couldn’t see anything wrong with it. I found that the main body of the faucet has two set screw like controls to separately regulate how much hot and how much cold can reach the reach the faucet stem. I opened both of them up (I think) to full flow. With the faucet cartridge removed completely, I turned the water back on and let the water shoot out of the faucet body across the tub at full pressure for several minutes to flush out the hot and cold water lines. I put it back together and that didn’t fix the problem.
I installed a brand new VersiTech Cartridge for Tub and Shower DANCO Model # 10773 Internet # 206165367 Store SKU # 1001492998 and that did not fix the problem. Still unpredictable, intermittent pressure. Works fine for 1 minute or 2o minutes, then has a problem. No way to predict whether or not you can take a shower or bath right now. Nothing else in the house has this intermittent pressure problem even when this tub/shower faucet does.