I have a Moen single handle shower. When I turn the shower handle on, very little water comes out of the spout. I have tried replacing the cartridge, but it's still the same problem. I thought, maybe there is something wrong with the housing. I covered the housing, and turned on the water to the shower. Plenty of water came out of the spout. I am at a loss. I have no idea why this is doing it. Any ideas? The cartridge I replaced is 1222. TIA.