Water in shower not hot

[Charles Haas Jr]

The water in my upstairs shower wont get hot. The sink in the bathroom runs quite hot as do all the other faucets in the house. That shower just wont get hot. The faucet is one of those single handle moen controls and even all the way to the left it wont get beyond lukewarm.

[Retired plbg1Participant]

If you have the sheets on the valve they will tell you how to ajust it, if you dont go to a search and ask them how to ajust a Moen shower valve. http://www.google.com is a good one.

[troutaParticipant]

The valve doesnt have adjusting screws or anything that I could find. Did a search online and there was nothing about adjusting it. The valve is just directly connected to the hot and cold pipes without set screws. Other than that the temp is only regulated by the moen 1200 cartridge that rotates within the valve.

I appreciate the help though.
Any other ideas???

[Mike McCoyParticipant]

If you take off the round trim you might see a large screw. That would be the balancing valve and they sometimes get stuck. You need to shut off the water and remove the screw,there will be a spring behind it. If you jiggle it a little it should unstick.
Mike

[troutaParticipant]

I can remove the cartridge and it seems like it is in fine shape. There is no balancing screw that I can find.

I think there is something strange about the plumbing in this house. When I close the valve that provides cold water to the hot-water heater, and then turn on a hot water tap somewhere in the house (not necessarily in this shower) water still comes out at full pressure…only it is cold. There is no shut-off valve for hot water coming out of the hot-water heater. How is cold water getting into the hot water pipes? Is this a normal setup for house plumbing or is there some cross connection that shouldn’t be there?

[troutaParticipant]

I fixed the problem. It turns out that the cartridge in that shower and the cartridge in another bathroom that I am not using at the moment were bad. I have now learned that even a bad Moen cartridge at a different location from the one experiencing temperature irregularities can be the culprit as it will allow cross flow of hot and cold water even if it is not being used. A guy at the hardware store gave me the trick to see if the Moen cartridge needs replacing:

Run the hot and then cold water on the faucet you are testing to heat/cool the hot/cold pipes. Turn that faucet off. With your hands on the pipes you just heated/cooled, have someone flush a toilet or turn on cold water. if you feel the cold pipe get warm (or the hot pipe get cold) right away, then the cartridge at that faucet is bad. It is allowing the cold and hot water to pass across the valve when the pressure on the hot or cold side goes down. This can lead to cold showers in another part of the house. You don’t notice it with the sink since the pressure drop when the faucet is turned on is less than in a shower.

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