The hot water pressure has slowly diminished to a trickle in both tub/showers. The pressure in the sinks is fine. I have a single valve in the shower which I completely took apart and flushed (turning on the water and letting it run through the valve) but the hot water still trickles. The sink 5 feet away works fine. What can I do to fix this?
Is there any kind of chemical I can pour in the valve? What do you suggest?
The heater is in a storage area in the garage.
We have one common incoming feed line into the house from the heater.
The valves and springs are clean in both tubs/showers.
One is a standing shower, the other is a combo tub/shower. Both have one ball valve.
There could be sediment in the hot water lines leading up to the shower valves. One thing you might try is to disassemble the shower valve the way you did, close the shower curtain, and turn the water back on for a moment hoping that sediment would flush out.
Your shower valves may have anti-scald protection that is out of adjustment.