A/C Question 1988 Mondial 3.2 | FerrariChat

A/C Question 1988 Mondial 3.2

Discussion in 'Technical Q&A' started by efinn, Jun 6, 2010.

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  1. efinn

    efinn Rookie

    May 25, 2010
    42
    Stamping Ground, KY
    Full Name:
    Eric
    I added a can of 134a to the A/C system today. The compressor was not engaging before freon was added. While adding the freon the compressor was kicking in and out quite a bit. After one can of freon I was getting cold air, the compressor was still cycling on and off. I found that tinkering with the blower speed control would effect the compressor engaging. My question, is it posible for the blower control to do this or was it just a coincidence? At the end of the day I had 54 degree air out the vents so I don't believe any more freon is needed.
     
  2. lightning

    lightning Formula Junior

    Apr 19, 2010
    551
    Stockport
    Full Name:
    Martin Oliver
    Does the top up can not have a gauge to tell you when the A/C at the required gas quantity?
    I'd suggest checking it with a gauge if you can.
    Still, at least you got it working so that's good.
     
  3. afterburner

    afterburner F1 Rookie
    Silver Subscribed

    Jun 20, 2008
    3,501
    Switzerland
    Full Name:
    Urs STEMMLER
    Fan speed has no direct control over the cycling.
    But there is usually a temp. sensor on the evaporator which cuts the compressor if freezing occurs.
    If you pump more warm air through the evaporator, it'll take longer to freeze, or won't freeze at all.
    There should also be max pressure switch that will cut the compressor once the system reaches that pressure. If you system is charged on the high side, it ma take very little compressor work to reach that point.
    Usually, there that max pressure switch is combined with a min pressure so that the compressor doesn't kick it the system pressure is below a certain level. That explains your compressor not kicking in before your reached the min system pressure.
    I am not a specialist on a/c, but had some "issues" in my Mondial's which force-taught me a few things... Anybody welcome to correct/add to my statements.
     
  4. efinn

    efinn Rookie

    May 25, 2010
    42
    Stamping Ground, KY
    Full Name:
    Eric
    Have found today that the A/C would cool fine for awhile, while driving, but would cycle on and off for no reason. After about an hour drive the blower stopped also, when we got back to the house, I checked the fuses found no problem there. Started tapping on the relays and the blower started again. I believe the relay labeled A/C plant is not making all the time. Thanks for your input folks.
     
  5. afterburner

    afterburner F1 Rookie
    Silver Subscribed

    Jun 20, 2008
    3,501
    Switzerland
    Full Name:
    Urs STEMMLER
    If you don't blow any warm air through your evaporator, it will freeze up very fast, with the resulting disengagement of the compressor. So make your sure your fan works.

    On the Mondial QV, as soon as you press any of the 3 A/C switches, the blower will start to turn very slowly, even if the fan speed control knob is in the off position.
     

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