Plumbing question for the group

[George Braun]

2008 H36. 5 Gallon Force 10/Kuuma 40500. Suddenly after working fine for 2 years, of course when I need to empty and winterize, the hot water no longer will flow from any of the 4 outlets on board. Cold side works perfectly well.
Main water pressure pump filtert is clean. The tank has a Watts MMV-V1 mixing valve to avoid scalding. i understand how all the supply lines are laid out at the front of the tank. I see no evidence of any type of filter or screen in the hot water supply side. Two questions for all the group. 1 - where would you look for a clog? 2 - how does one remove the mixing valve?

 

[George Braun]

does anyone have an educated guess on which version of the Watts part this is. the tank side has a union, a 90, then i'm not sure of the next part. The line side looks to be the same but connects to the old school 15mm flex tube,

Has anyone successfully taken this apart and put back together? My though is to work out from the tank and that's the first stop. Of course, like all boat projects, you need 2 elbows to reach the friggin thing.

 

[Davidasailor26]

The attachment you posted seems to be of Yanmar belts, not the water heater.

My guess is the issue is with the mixing valve. I know some residential mixing valves won’t let any water through on the hot side if there’s no pressure on the cold side. Have you already run the cold side empty? If so it’s possible the air in the lines is preventing enough pressure to open the hot side of the mixing valve. If it’s possible to remove the mixing valve for the remainder of the winterizing process I’d start by trying that.

 

[Ralph Johnstone]

The attachment you posted seems to be of Yanmar belts, not the water heater.

Maybe he feels that a good belt, albeit a Yanmar belt, would solve the problem. This is more likely the belt he had in mind :

Your mention of the mixing valve is 99.99% correct. With nothing unusual happening before the failure of the mixing valve, either the failure of the valve or a lack of cold water pressure are the usual suspects.