Hi, the upstairs shower is only trickling when turn to hot. It's a one knob with hot/cold. The two sinks in the same bathroom are working just fine with hot. One thing, this shower is hardly ever use by the family. What could be the problem?

Thanks

Hi Gator,
Sounds like the inlet ports may be clogged up. Shut the water off and open up the valve. Remove the cartridge and check the inlet ports for trash and clean them. Now turn the water back on the flush out the supplies, reassemble and test. Work better now? Regards, Tom

Tom, Thanks for your time. Sorry to sound stupid but I'm not quite sure where is the shutoff valve. I have attached a picture of the heaters. Can you please point out the shutoff valve and the cartridge? Thanks.

Hey Gator,
Sorry for the confusion. I wasn't referring to the water heaters I was asking you to open up the shower valve and clean out the inlet ports of the cartridge. Regards, tom

Tom,

Is this the shower valve?

Tom,

Is this the shower valve?

Yes, does it say Moen on the face plate? Tom

Yes, it does.

OK, Tom, we're in business.

Shut th water off to the shower valve and since you've already pulled the knob, all that remains is to pull the chrome stop tube out. You will see a brass clip holding in the cartridge. Before you pull that clip, PAY VERY CLOSE ATTENTION AS TO HOW THE CARTRIDGE AND THE CLIP ARE POSITIONED IN THE VALVE BODY, YOU ARE GOING TO HAVE TO INSTALL IT THE SAME WAY. Pull the clip and take and see if you can pull the cartridge clear of the valve housing by pull up on the stem.
. ( For those'hard to remove cartridges' Moen makes a cartridge puller that can be purchased at your local plumbing supply house.)
After you get the cartridge out look down on the bottom at the inlet ports and clean them out. If the cartridger looks too bad then replace it. Now turn the water back on for a minute to flush out the supplies. You should have a strong stream coming out of the open valve body. If not click on back. Reassemble and test. Better now? Regards, Tom

Tom,

I pulled the clip out without a problem but am having problem with the stem. I also went to Home Depot, looking for the cartridge kit but they didn't have one. Am I doing something wrong?

You didn't have to pull the plate but that's OK. Go to a plumbing store and ask for a Moen 1200 cartridge. Also ask if they stock a Moen Cartridge Puller.
This tool works like a wheel puller in pulling out those stubborn cartridges. Good luck, Tom

Tom,

I get the Moen 1200 from Lowe's, and it looks completely different from my shower stem. Also got the cartridge puller from Home Depot. When I pull on the stem, it feels like something is holding on to it in the back. I'm afraid to pull too hard because I may break something. I'm about to give up and call the plumber.

Tom,

I get the Moen 1200 from Lowes, and it looks completely different from my shower stem. Also got the cartridge puller from Home Depot. When I pull on the stem, it feels like something is holding on to it in the back. I'm afraid to pull too hard because I may break something. I'm about to give up and call the plumber.

What's happened is that the "O" rings on the cartridge have swelled up and are binding against the valve body. That's where the cartridge puller comes in. Set the puller up by fitting it in the slot and tighting the screw. Now try to twist, (not pull) the cartridge to break the "O" rings free. Once you can twist the cartridge turn the handle and remove the cartridge. Let me know how the cartridge is different. Regards, Tom

The stem on the shower is a lot longer than the Moen 1200 I got from Home Depot.

Have you got the cartridge out yet?

Ok, I'm able to pull the stem out but there's a lot of water coming out so I pushed it back. I pulled the plate in the room behind the shower but it's just sheetrock. Would the shutoff valve be behind the sheetrock? Is there also a main shutoff valve to the whole house?

I found the main shutoff valve.

Tom, I was able to pull out the cartridge. The old one looks completely different from the new one. The old one is a little bit wider than the new one. From the picture, the old one is on the left.

You failed to mention that your shower valve was a Moen Posi-Temp Model. I was giving you information for a regukar Moen valve.
If you wish to replace the cartridge click on ; http://www.moen.com/browsecatalog/catalog/search.cfm?stype=category&ptype=w&product=2203&category=2263&finish=2178
The cartridge you need is #1222. However since the cost is $54.55 which is steep let me give you a link to a cartridge rebuilding kit for around 10 bucks;
http://www.moen.com/browsecatalog/catalog/details.cfm?stype=category&ptype=w&product=2203&category=2263&finish=2178&crow=1&details=product&sku=96988
And in addition let me give you a link that will give you specific instructions; http://www.moen.com/shared/pdf/instruction_sheets/INS746E.pdf
I'm sorry about the confusion. Take the cartridge you purchased back for a refund. Don't forget to turn the water on and flush out the supplies before you reassemble .good luck, Tom

Tom,

Thank you so much for your help. It looks like the cartridge is the problem. I put another cartridge from another shower and the problem disappears.