How Dun wrote:
Old biscuit called it. We have the Atwood XT with mixing valve. Can it
be repaired or must it be replaced ?
They are better replaced. I doubt you could clean one out and then get the mixing valve to function correctly. The purpose of the XT series with the Mixing valve is to produce 16 gallons of hot water from a 10 gallon tank. DO NOT REMOVE IT. As Jetcare stated you will have extremely HOT water without the mixing valve. The normal temp of a RV water heater is 130 degrees. As Jetcare stated, the XT produces 160/170 degree water which is way above scalding temp. The Mixing valve takes that extreme hot water and mixes it with cold to produce 130 degree water output. Doug