MCI OTR AC Help

[peterbylt]

I am hoping someone can provide some guidance.

When I started the conversion process on this bus (1989 MCI 96A3) over two years ago the OTR AC worked really good.

Since then the Bus has sat for the better part of two years, starting it up occasionally to move it around the lot I have it in, I am now getting to the point of wanting to use the Bus and the OTR AC does not blow cold.

When I flip the Dashboard switches everything starts, the compressor kicks on, I can visually verify the clutch is engaging and the compressor spins, when the switch is flipped you feel and hear the compressor load on the engine.

The condenser and evaporator fans come on, I can see fluid in the Receiver tank in both the top and bottom sight glasses, I can see no sign of any flow or movement in the sight glass when the switch is on and the compressor is engaged.

When I touch the inlet and outlet fittings on the compressor, one is slightly warmer than the other, but neither one is significantly hot or cold, not like I am used to on other units where it is too hot to touch or cold and sweating.

The refrigerant fill valves at the compressor are the quick connect R134a type, not the screw on type that I would associate with R22, I will assume that the conversion was done to R134a, there is no marking or tags to indicate what the Refrigerant is.

I am thinking either the dryer/filter, or the Expansion valve is blocked, if one of them is blocked, shouldn?t the over pressure sensor shut the compressor clutch off?

Both the Main and drivers Air are not blowing cold.

Does anyone have a suggestion of how to procced?

I have just ordered a set of gauges from Amazon to test the pressures.




Peter

[chessie4905]

I'd say it is low on refrigerant from lack of use. The older ones would leak past main compressor seal if not run regularily.