Moentrol hot water flow issue

[Michael Ewins]

The hot water flow is being reduced in my shower/tub controlled by a Moentrol (I think it's an 1198 model), and I hear a clunking noise when it shuts down the pressure. I've checked the balancing spool and it seems fine. I've also now replaced the cartridge. I uploaded a video showing the issue:

Any suggestions are greatly appreciated.

 

[WorthFlorida]

Two more things to check. Check and turn the hot water shut off for this fixture and with the trim piece off, check if there is a stop in the valve body. Either one the washer for these may have failed and as it disintegrates the pieces could be block the flow. Does the sink in this bathroom have good flow?

 

[Sponsor]

 

[Michael Ewins]

Thanks for responding, WorthFlorida. The valve is definitely open but I will check the stops.