Moentrol shower valve won't run hot water for more than a few seconds.

[RAYMOND GEISMAN]

Good afternoon. I have a Moentrol shower valve, about 20 years old. several times in the past the hot water flow would slow down, and by opening and closing the hot water shutoff on the valve, it would fix the problem This time it made it worse, making the shower unusable. I replaced the spool and replaced the cartridge, and flushed out the system (not tremendously hard, as I did not want to make a giant mess). and I did get an adequate amount of water out initially, but when I tried it this morning, it came out OK for a minute or 2 but then the flow decreased and the temp decreased, again making it unusable. Moen is sending me a new stop valve. Any other thoughts on what I could do to help this. I (not the shower) am in a little hot water at home for making things worse(and rightfully so).

Also, I think I've been opening and closing the hot water stop valve. Is the hot water shutoff the one on the left as you are looking at the valve from the front, and the cold water is the one on the outside of the spool on the right? Thanks.

 

[Michael Ewins]

I am also interested in a solution to this. I am having the same problem.

 

[Sponsor]

 

[Terry]

Normally the hot enters on the left and cold on the right. Though sometimes plumbers reversed that and would spin the cartridge 180 degrees to flip the temperatures on the valve. One of the nice things about the valve was this ability to make a correction after the fact.

For the valve to operate correctly, it needs even pressure from both sides. If one stop is turned down or off, it will compensate and lower the overall pressure.