Help with a shower that turns cold after a few minutes, after replacing the cartridge

[MitchwFSU]

Hello,

Just recently our shower started going cold after a few minutes. The other shower in the home does not do this. Therefore, I assumed it was the cartridge. It's a Moen PosiTemp assembly and I just replaced the cartridge with a generic 1225 cartridge I bought on Amazon. Upon testing, I find it still goes cold after a few minutes. A bit disappointing.

The heater is a Rinnai gas heater. The other shower works fine, as do all other faucets.

Did I mess up buying a generic cartridge? Otherwise, nothing else has changed since this problem started to occur (about 2 months ago). Any suggestions would be greatly welcomed!

I'm in Pinellas County Florida, if that matters. Thanks in advance for any insight. Mitch.

 

[TomFOhio]

Mitch are you able to shut the hot and cold off to the shower. If so turn on just the hot only and see
what kind of pressure you have. You'll have to pull the cartridge. In order for that faucet to work
properly both the hot and cold have to be on with cartridge in.

 

[Twowaxhack]

I would probably start a repair like yours by replacing the knockoff cartridge with a moen factory cartridge.

 

[Twowaxhack]

Also make sure your hot water limiter is properly set so you can get enough hot water to mix.

 

[arctic bill]

Just so you know the b 1255 cartridge by moen is guaranteed for life . that the old original to any real plumbers store .

 

[TomFOhio]

Our supply house won't take them anymore for warranty trade. We have to call Moen and take care of it
ourselves or have the customer call. Real bummer.