Moen posi temp valve issue

[Cmct1181]

We have a brand new moen posi temp valve and new cartridge along with new plumbing installed. When turning on the water, as you get hotter the water pressure gets lower. Only seems to be when you get to all hot water (not mixed with cold) We’ve replaced the 1222 moen cartridge and it still does it. Not sure if this is part of the posi temp design or an issue with the valve. All other faucets in the house are fine.

 

[John Gayewski]

That's not an uncommon thing to a point. How much lower are we talking? If you think about it when the hot and cold are mixed you have double the available volume of water. If you open the valve all of the way and close off the cold your only running one side which will result in less volume.

If the "pressure" drops off a lot (more than it should) there could could be a problem, but I'm not sure you actually have a problem.

 

[Sponsor]

 

[Cmct1181]

Pressure drops a noticeable amount. Not enough to be a trickle, but definitely less than desired pressure. Full cold pressure is higher than full hot pressure. Shouldn’t the pressure balancing valve regulate pressure from cold to hot making it equal?

 

[WorthFlorida]

This was posted twice. My suggestion is also to check the temperature limit stop. It might be going past full on past the 9 o-clock position.

How to Adjust the PosiTemp Temperature Limit Stop

The article will provide step-by-step instructions on how to adjust the maximum water temperature produced by a PosiTemp shower system. Moen recommends limiting the maximum temperature flowing from …

solutions.moen.com