Tri-Pac questions

I have a Thermo-King Tri-Pac APU on my truck. For a few weeks now, when I would first start the APU, it would run fine for a few seconds, then bog down when the A/C compressor kicked on. I could stop it, restart it, and it would run fine. Today, I started it, and it's blowing hot air. The compressor won't kick on, though the fan on the condenser mounted on the back of the cab will run. I'm figuring it's been low on refrigerant for a while now, and finally got low enough to not run the compressor. I have a big canister of R-134a and the gauges/hoses to charge it (and a squjirt bottle of soapy water to find a leak), but can't seem to find where to put the refrigerant in. I'll be taking off the lower cover and looking in the area of the compressor tomorrow, but figured I'd ask if anyone here knows offhand where to put the refrigerant in. Also...it does use R-134a, right?

 

Thanks, I'll give them a call. I know with regular automotive A/C, once it gets very low on refrigerant, the compressor won't kick on until more refrigerant is added. This is a function to protect the compressor, as the refrigerant also carries with it the compressor lubricant. No refrigerant = no oil to compressor = burnt up compressor fairly quickly.

So I will likely need to add refrigerant to get the compressor to kick on. I could find out for sure, if I could hook my A/C service gauges to the low pressure fitting. Just gotta find the fitting

If I don't find it by Monday, I'll give those guys a call. I figure I also want to get my hands on a technical manual for the thing, too.