7740 air condition issues

[swamprabbit2]

I have a 7740 that the air isn't working right. When the weather was cool it worked great when I didn't really need it. Now when its hot it may work some times. If it does come on when it cycles it will not come back on.I jumpered the pressure switch by the compressor didn't help. I jumpered the one on the left side in top of the cab and it works great, but it dosent cycle. What next?

 

[RickB]

Get a set of service gauges and learn how to use them or pay somebody that has them and can. Servicing A/C without gauges is a lot like fixing electrical circuits without a VOM or test light. Success happens more by accident than design when flying blind.

 

[swamprabbit2]

I have gauges and know how to use them. Freon is ok. My problem seems to be more like a pressure switch holding the unit off. That's why I started bypassing pressure switches.

 

[RickB]

OK it sounded like you were flying blind. What are the pressures when it cuts out and refuses to come on?

 

[swamprabbit2]

When it is operating normally low pressure and high pressure are in range. When it kicks off pressure is HIGH! I dont remember the exact pressures but they are up there. I would have to hook gauges up to give you exact numbers.

 

[RickB]

Faulty TX valve is most likely.

 

[swamprabbit2]

Where is it located?

 

[RickB]

At the inlet to the evaporator coil.

 

[swamprabbit2]

Thanks for the info.