Dash AC intermittently blowing cold air, then hot

Discussion in 'Class A / Diesel Pushers' started by mhbell, Oct 12, 2015.

  1. mhbell

    mhbell New Member

    Dash AC intermittently blowing cold air, then hot
    My Dash AC blows cold air when the engine is cold, but after it gets warmed up it blows hot air. I assume that it has a Evans Tempcon Electronic Coolant Valve that can shut off the coolant to the heater core when the dash AC is turned on. There is also a Vacuum Pot on the bottom of the AC shroud which I think operates a flapper blending door between the heater core and the AC. With the engine cold and idling, I get cold air. But going down a flat highway engine not under load I get hot air. Pulled into a rest area and with engine warm, and at idle I still get hot air. Is it the Evans Coolant Valve that is bad, or something in the controls. I have heard that some replaced the valve with a manually operated ball valve to use during the summer months. Can anyone shed some light on this and is there a way to check it out.
    Mel
     
  2. C Nash

    C Nash Senior Member

    Have you checked to see if the clutch on the compressor was still engaged when not cooling? Probab;y a door not operating right allowing the heater to out do the cooling. Let us know what you find. What RV do you have?
     
  3. mhbell

    mhbell New Member

    It has to be a Vacuum Leak or kinked line because now it is blowing through the defrosters no mater what position the mode switch is in. That is a safety feature when Vacum is lost.
    Mel
     
  4. Samaran

    Samaran Junior Member

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