[urq] a/c question

[Buchholz, Steven]

... I'm not an A/C guy, so I may be wrong on this, but it sure seems to me
that something is plugged if you see the compressor cycling on and off.  I
would imagine that what is happening is that the compressor pumps up the
system before the blockage ... the overpressure switch shuts the compressor
off and then the pressure bleeds back down.  I suppose the quick bleed down
might indicate the reed valves in the compressor are bad too ... perhaps a
result of the blockage.  It is my understanding that the expansion valve is
the most likely point where a blockage could occur ... I know you say it was
replaced, but if there any chunks floating around the system it might cause
the new valve to get plugged ...

Steve B
San Jose, CA (USA)
> 
> I had my a/c system checked out...new expansion valve, new 
> reciever drier, new green o-rings and new gaskets and seals 
> in the compressor. It held vacuum for 30+ minutes. Charged it 
> with R-12 replacement to correct pressure. Turned on 
> compressor. Fine, but no cold air. At anything above idle the 
> compressor cycles rapidly, and i could watch as one of the 
> gauges would go to 30, drop down to zero then back to 30 in 
> tandem with the cycling. A/C tech says compressor is bad. Is 
> there something else to check first?