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Ronaldlee's avatar
Ronaldlee
Explorer
Oct 06, 2020

Water Heater Mixing Valve Issue

I have an issue with the mixing valve in the motorhome. Sediment keeps stopping up the valve and does not allow any hot water to flow. I flushed the water heater and had a new valve installed and on the first trip out it did it the first time I turned the water heater on..Any thoughts as to what I can do.. It is in the shop again and they want another $400.00 to clean the mixing valve and reinstall. This is a 10 gallon Atwood. They also said the water heater may be deteriorating? Can anyone offer any suggestions.
  • inline strainer, couple bucks ,would catch the sediment.p.s find a different dealer should not take a hour to take apart clean back together.
  • If you don't have a sediment filter for all pedestal water then you may need to replace the HW.

    If the "mixing" valve is the winterizing bypass valve then that suggests rather large sediment. Mixing hot/cold water usually occurs at the faucets.
  • I posted in your 'other' thread but is got closed

    Here is the info concerning your Mixing Valve


    **Highly doubt it is due to tank...tank is Aluminum with a Zinc Cladding

    Your issue is build up of Scale/calcium

    Need to do a Vinegar Soak

    2 parts Vinegar to 1 part water...FILL water heater via T&P Relief valve (remove add solution reinstall)Then allow water heater to go thru 4-5 heating cycles
    *Let it run overnight
    Then drain/flush crud from tank thoroughly
  • Remove the mixing valve and replumb. Remove the thermostat and replace it with a standard 140° stat. Those mixing valve systems from Atwoods were nothing but a problem from the get-go.

    Richard
  • RLS7201 wrote:
    Remove the mixing valve and replumb. Remove the thermostat and replace it with a standard 140° stat. Those mixing valve systems from Atwoods were nothing but a problem from the get-go.

    Richard


    XT Models (Mixing Valves) use a 160*F T-stat
    as mentioned replace with a standard Atwood T-stat (140*F) should you delete the mixing valve
    You will also need to change out the t-stat Brown wire connector from a 'PIN' type (used on XT) to a 'Small Spade' type (used with the 140*F T-stat

    Mixing Valve in concept is/was a good idea......higher water temp allows more available hot water due to outlet temp controlled to 130*F from Mixing Valve
    Unfortunately scale/calcium in water source clogs up the Hot inlet side of Mixing Valve causing luke warm/cold water output
  • A water softener along with the vinegar flush every year has worked for me. Last year I installed a whole house RO system. The campground in Florida has questionable water so this is a big improvement for us.