Over the Road Air Conditioning

[Hi yo silver]

The over the road A/C on my MC-9 isn't working.  If I can have it fixed without sacrificing both arms and legs I want to.  Any advice regarding basics to check for first?  Here's what I know.  The fan blows hot air, the belts are in place, turning the compressor, there's just a trace of liquid visible in the bottom of two sight glasses on the cylinder(?) near the condenser fan.  Should the lower sight glass be full?  Anything in particular I should know or watch for when I go naively to an air conditioning shop for evaluation?  Who's the expert on the BB?  Thanks guys. 

Dennis 

P.S. I sure like this spell check feature.

[tekebird]

needs recharged

[Nick Badame Refrig/ACC]

Hi Dennis,

I could be low on refrigerant like Doug said. However, are you sure the compressor is turning and not just the clutch?

Another variable is a restriction... because you stated that the air comming out the vents is not cold at all. With a restriction, you will

still get some liquid partially flowing past the sight glass and have no cooling at the vents.

If you were just short on Refrigerant, your compressor would cycle on and off and you will get some cooling.

If the system is empty, the compressor wouldn't come on at all and therefore, you will Not have any movement in the sight glass at all.

You could always plan a trip to my shop. I promise I won't charge you an arm and a leg..

Good Luck
Nick-

[NJT 5573]

Make sure the clutch is locking the compressor and that it is turning. One of my wires on top of the compressor causes this problem once in a while.

Most of these units work with a large radiator for heat and combine the A/C and heaters. If the engine hot water valves are not turned off, the hot water will over power the A/C and blow warm.

I have a Thermo King unit in my Eagle. Thermo King has treated me well. My unit is basically the same as most over the road refrigerated trailers use so T/K coast to coast is familiar with any repairs I need. Last time I had it checked out (3 years ago) and had refrigerant added it took about an hour and I spent less than $200.

Obviously, Nick is the expert on this one!

[Nick Badame Refrig/ACC]

Good catch 5573,

Yea Dennis, make sure you turned off your heat valve...

Nick-

[Hi yo silver]

Thanks, all.  I'll close the heat valve.  Didn't think of that.  I'll keep you posted, Nick.

Dennis