Hello all - I'm hoping you can help with this issue. I have a stand-alone shower with two taps. There is a standard shower head with a diverter to a hand-held shower head. I'm guessing it is an original setup in the house, which makes it about 30 years old. The hot water occasionally drops away, even though the cold tap is barely on and the hot is full on. It eventually comes back, but it can take a few minutes. Unfortunately, there is no access panel - drywall on one side, tile on the shower side. There are two other showers in the house, and no problems occur with them. There is also an on-demand water heater. Any thoughts on the cause of the hot water drop? I'll try to provide more information if needed. Thanks! G.