I have a Moen shower faucet, one with a single handle, for hot and cold water. The problem is that when I turn the water on, the cold water works fine with great pressure. However, when I turn it about half way where the hot water should start coming out, the water pressure just turns to a drizzle. This is occurring in my spare bathroom, in a house I just moved in to, so I don't know how long the problem has been going on, or if the faucet is even installed correctly. I have perfect hot water flow in all other faucets in the home. Anyone have any suggestions on what the problem might be?

Your cartridge inlet port on the hot side is clogging up. I will give you the Moen tutorial page so you cann remove the cartridge yourself. Once the cartridge is out have someone open/close the main quickly to blow out any more debris. Use a tooth pick or comressed air to clear the port and then reinstall after applying silicone jel or plumbers grease to the valve body insides and cartridge. http://www.moen.com/consumersupport/installation/moen0132/moen0132.cfm

Ballangerb1 gave you great advise, if the problem happens again I suggest that you check the dip tube in your water heater. Some dip tubes deteriorate after a few years and stop up small openings. I would really think this is your case if your aerators have been stopping up.

Letmetellu makes a good comment. Many clogs are water heater related and dip tubes can deteriorate. Failure to flush a heater yearly or sooner also allow calcium and other debris to collect in the heater.

I agree with ballengerb1 (Bob) and letmetellu, but if the dip tube is failing wouldn't it effect all the other faucets, what I hear is only one shower faucet is at fault, I would defiantly go with Bob's first recommendation, remove the cartridge and flush the faucet, if that will not work then change your cartridge it is P/N is 1222, please open the folllowing link for exploded parts, also FYI all Moen faucets are life time Warranty, for the Cartridge replacement open Bob's Moen tutorial link, good luck.

John

http://www.moen.com/shared/pdf/L82691pt.pdf

John, I know exactly how you are picturing the dip tube issue in your minds eye. However, dip tubes come apart in fairly large chunks and a piece of junk may flow down a supply line and just plug the very first fixture to use hot water. I am embarrassed to admit my tube is shot, I have the parts but not the time. The same kitchem aerator gets chunks once a week and I clean it. I'm off work for 2 weeks and this is the top of my list along with a replacement sacrificial anode rod.

Thanks Bob, for your detailed respond and I agree with you as I said on post #5 but I will go with your first recommendation to remove the cartridge flush the faucet or change the cartridge. Wish you good luck with your Dip tube and Anode rod replacement and wish you happy holidays, Thanks.

Regards,
John