Ok so when you turn the valve and antifreeze fills the tank here is the fix.
Atwood water heater mixing valve problems.
This can happen if you have a weak gas control magnet or if the thermocouple needs to be replaced.
Impurities in the water can cause your atwood water heater to malfunction.
Saves weight while fitting in the same cut out.
One of the most common problems with atwood rv water heater is a pilot outage.
Sometimes you need to move adjustment back forth to clear.
Tamper proofing glued allen head screw the knob to adjust output temp is pain to remove.
I had to remove the valve because i did not know they had put glue inside the screw hole where the torch bit went.
There is still a check valve on the lower cold side so back flow to the fw tank.
Problem seems to be solved.
Yes can soak it in clr or hot white vinegar to clean and then rinse thoroughly.
This unit is operated on propane gas and can only be ignited inside of the trailer using an on off remote switch.
Which is why its discussed in this airsteam forum and just about every other rv forum.
It took about 15 minutes of flushing my water heater before it ran clean with no chunks of crud coming out.
The mixing valve is on the back of the water heater and mine has a red knob.
Fired the heater up and with the new valve the water temperature at the tap is 130.
10 gallon water heater xt exothermal mixing valve for xt water heater atwood xt water heaters advanced water heater system featuring exothermal technology the atwood xt 10 gallon water heater provides the equivalence of a 16 gallon unit without increasing the space required.
Drain the water heater by removing the drain plug then refill the heater.
The problem is that the water heater thermostat is calibrated to make scalding hot water then the mix valve cuts that down to a more reasonable temperature for use.
Recommended cleaning procedure is to soak the mixing valve in hot vinegar to dissolve any hard water deposits blocking the screens.
If it is not too old hen you can try cleaning the orifice and see how it goes.
For poor pilot flame you would need to replace the orifice.
I will be cleaning out the water heater more often now.
Atwood has tried to make the valve tamper proof.
This gives you more hot water than the capacity of the tank alone but adds to the complexity and maintenance issues as you see.
I checked my atwood heater manual and also nothing mentioned on the mixing valve.
Atwood 6 gallon water heater unit is pre set at temperature 140 degree fahrenheit which is adjustable from 110 to 150 degree fahrenheit.