Well, everytime I think I get my HVAC system sorted something else needs repair.
I just recently converted my AC to R134, now I find the AC compressor runs about 10 secondes, then cycles off, then runs for 10 seconds etc etc..

I can hear the condensor fan running, so does this mean the 3 pressure switch is faulty?

On another note, it seems as if the rear blower runs whenever the ignition is on, regardless of ccu setting.I have replaced the fan, ballast resistor, and relay.I suppose this is CCU related?

Lon

 

I have searched the threads, and I have seen where some say the cycling is normal, and others say it should stay on for more than 10 seconds. I am really confused. I live in a very hot area and I wish to have the AC work at its optimum level. I know It will not be as good as my other autos, I just want it to work as it should.

Thanks,

Lon

 

A cause for your compressor to short cycle could be because your low on refrigerant charge, from a leak or a low intial charge. When there's not enough 134A the compressor draws down the suction side and kicks off because of the low side pressure switch.
Hope this helps, Kevin

 

Kevin,

Thanks for the reply. Im certain it isnt low on R134, because it was cycling 5 mins after charging. Prior to charging it held vaccum for 30 minutes.
Thanks again for the help.

Lon

 

I believe it's the 3-way pressure switch which causes the compressor to cycle on and off. I've heard people say before that if it cycles a lot, that can be the cause. But I've never seen anybody state what's "normal" cycling. Mine cycles about every 10s or so - sometimes stays on for 20s but not usually any longer. My air con is not as cold as it should be (25C ambient, 12C at the vents) but for the UK it's good enough.

 

Dave,

Thanks for the info. I too would like to hear from others as to what the normal cycle should be. Maybe Adrian or Randall can pipe in. I dont mind replacing the pressure switch if it is faulty. I would hate to replace it only to find out the compressor still cycles every 10 seconds.

Thanks Again Dave,

Lon