Hello:
I have a Moen positemp bathtub/shower. I wasn't getting any hot water (the house is a new rental, a few years actually, and this 2nd bathroom may never have been used!).
I pulled out the Moen cartridge, inspected it, put it back in as before (H/C at the top), and still only cold water on full rotation.
I next pulled it out again, put the H/C on the bottom, and now I get only HOT water.
So what is going on... is this therefore a bad cartridge. I don't know how to adjust this otherwise. My main bath has the same, but before I try to pull that one out (believe it was a royal pain pulling out that cartridge, finally a pair of strong needle noses that can wiggle the cartridge, is what it took), can anyone tell me that it is likely the cartridge? Is there something I can do to the cartridge to repair it (as mentioned, it is in good condition, this bath has not been used much).
Thanks for the help if possible.

If you switch the cartridge and the temp changes, it sounds like a plugged orifice in the cartridge. The holes are small end easily plugged.

I agree with ma. Sounds like the hot side of the cartridge is plugged. Pull the cartridge once again and inspect completely. You can push the center stem down out the bottom of the cartridge to fully inspect and clean, however take care when reinserting the stem, as the orings tend to catch and bind. If you find no obstructions, you may have sediment buildup causing the balancing device to stick. Play around and see if you can't get it all cleaned up, or merely call 1 800 buy moen, and ask for a new cartridge. Moen has a lifetime warranty and may very well send you a replacement cartridge for free. If they won't, because you are not the original purchaser of the fuacet, simply go to the nearest pluming supply store and buy a new cartridge. 99 percent sure this will cure your problem.. Do know that these cartridges can be a bit pricy, so I would contact Moen first to see if they won't warranty it.

Thanks.
Have it all apart, and stem through, and also plastic end off. But can't generate any kind of movement (of balancing device?)... the 1st set of holes are clear sortof, but 2nd set inline with 1st are blocked. I'm wondering whether they should be inline?
I might only know by taking apart the 1st working bath and inspecting its cartridge... hmmmm.

Just need some clarity on the balancing device (inside stem?)... is it supposed to move freely either laterally or rotation? It doesn't. So am trying to figure out how to make it move

You know Moen will replace this cartridge for free don't you? I'd just replace it. Warranty Information for Moen Faucets (http://www.moen.com/consumer-support/warranty)

You know Moen will replace this cartridge for free don't you? I'd just replace it. Warranty Information for Moen Faucets (http://www.moen.com/consumer-support/warranty)

Thanks... yeah I've given up trying to unstick it. I read somewhere else that in general this will happen to these cartridges if they sit along time with only cold water usage. So will call Moen see what they say... else fork out for a replacement. Thanks for all the good advice nonetheless.
Advice to some: don't really need a cartridge puller.. since these cartridges can get very stuck... can use long needle nose pliers, and just grip the plastic part (not the brass stem) and wiggle it left and right about a minute... thats pretty much all you need.. then can pull it out.

"wiggle it left and right " not recommended since you can mark or score the valve body. The puller pulls straight out and so should you. You can buy a puller but renting them is cheap. moen cartridge puller - YouTube (http://www.youtube.com/watch?v=3f5-pMiyeSE)

TFL. Im sure you meant twist left and right, not wiggle left and right? If so, you are correct, the pulling device that actually comes with the cartridge is designed to twist the cartridge left and right, and the lip of the valve body pushes it out while you twist it. I also agree a pair of needle nose does the trick quite nicely. I have been using my leatherman for years to pull these cartridges with no issue.

GOT IT FIXED! Yes the neednose is just to twist left and right, and sure it might score the plastic a little.
Well, I finally figured it out and fixed the stuck cartridge (Moen 1222).
WHITE VINEGAR... man's best friend when it comes to cleaning calcium deposits. When you remove the cartridge, pop out the end plastic stop. If you insert a screwdriver (while holding the other brass end) and cannot rotate the balancing device, then its (calcium etc) sediment stuck. So what I did was, remove the stem from its plastic body (ie with end cap removed you can just push it all thru)and then remove the O-rings carefully (I wasn't sure if the O-rings like vinegar but wasn't sure how long it would take to soak it).
Put enough white vinegar into a small glass, immerse the whole stem assembly in it for about an hour. Then holding the brass end, insert a screwdriver (flat head) into the other end, and after a little twisting, it should eventually rotate freely. Works great now. Just make sure to put the plastic end cap back in and orient at right angles to the internal stems (I didn't do that at first and was only getting a little warm water finally).
Hope this can help others. My cartridge was actually in very good shape, but I guess the trick is, when you have bath not being used often make sure you turn it on cold/hot once in awhile to help prevent buildups (particularly if its only ever been turned on just for some cold water).
Cheers!

Thanks for the update. Good job. I forgot to mention that you should be able to shake the cartridge back and forth and hear the balancing device slide back and forth. If it doesn't slide, you can do exactly what you just did.