Question about installing a mixing valve on the water heater

[leecea]

I bought a Cash Acme Brass Thermostatic Mixing Valve to install with my new Kuuma 6 gallon water heater.

I assumed I would screw it directly into the hot water output on the heater.

But the valve is much heavier than I expected. I am worried that the weight of the valve with three water hoses attached will put a lot of strain on the water heater fitting. Especially if the boat is bouncing around in chop. I am worried that I'll damage the heater.

Now I think I should mount the valve separately, with a hose running from the heater hot water output to the valve.

Has anyone else installed a mixing valve like this? How have you done it?

Thanks,
Andy

[Tupaia]

The water heater should be more than strong enough to support the TMV.

[dougcn]

I did exactly as you are describing. I mounted the mixing valve on a bulkhead adjacent to the heater with connections to the heater by hose. It’s worked well. Great addition by the way, it significantly extends the hot water output of the tank.

[wrwakefield]

Out IsoTherm water heater came with a mixing valve installed directly on the heater [right side of horizontal grey tank in the work-in-process photo below.]

We have had zero issues with it since installation in 2015.



FWIW

Cheers, Bill

[Jammer]

Originally Posted by leecea

Has anyone else installed a mixing valve like this? How have you done it?

I installed two mixing valves in my last stick house. Different brand, same idea.


If you install them right at the outlet there will be some thermosiphoning that will keep the valve hot and that can lead to a brief splash of scalding water at the tap under some conditions. Better to install the valve below the water heater (or at least as low as possible) and run some PEX between them with an insulated sleeve over it.


I would be concerned too about the long term fatigue effects on the wall of the water heater. Water heaters are expensive and time consuming to replace so I would err on the side of caution.

[leecea]

Thanks everyone for all the advice. Very helpful. Time for me to do some thinking and get this done. Looking forward to having hot water again

Regards,
Andy