[DML] Re: A/C problem: compressor is not cycling

["Marv Hein" <marvhein@xxxxxxxxxxx>]

Did your A/C ever cycle properly?

A PO removed a diode on my car which caused the compressor to engage 
and stay engaged as long as the fans were on.  I'd be riding along 
in VENT and suddenly get a blast of cold air because the otterstat 
kicked the cooling fans on. With AC turned on, the fans came on 
immediately and I never saw any cycling either.


Marv
#10820
AZ-D

--- In dmcnews@xxxxxxxxxxxxxxx, Travis Graham <tgraham@...> wrote:
>
> Hello,
> 
> After a month of sweating it out, I now have air conditioning 
once  
> again, but something appears to be wrong: the compressor runs  
> constantly whenever the A/C is on.
> 
> Known quantities:
> 
> 1) The system has a small leak somewhere - it loses enough  
> refrigerant to stop working after approximately 3 months.  I'm  
> working on finding the leak, which is why I'm charging it up.
> 
> 2) I charged the system yesterday and noticed that the compressor 
ran  
> constantly.  Thinking that somehow I overcharged it, today I 
recycled  
> the refrigerant, evacuated the system to 29 in-Hg for 30 minutes,  
> held that for another 30 minutes (did not lose a bit of vacuum), 
then  
> charged the system with 2.0 pounds of R-12 (purposefully  
> undercharging it initially to see if it would cycle more  
> frequently).  The air at the center vent is cold (40 deg. F when  
> moving, around 60 when sitting), but the compressor still does 
not  
> cycle (at least, as far as I can tell; I do have Fanzilla, so 
it's  
> tough to tell if it's cycling when I'm moving).
> 
> 3) The ambient temp. is a humid 90 degrees F and my cooling fans 
are  
> running constantly with the A/C on.  Pressures from the manifold  
> gauges are...
> 
> rest pressure: 69 psi (low and high)
> 
> @ idle:
> low side: 42 psi
> high side: 155 psi
> 
> @ 2500 RPM (car not moving):
> low side: 28 psi
> high side: 206 psi
> 
> 4) My orifice tube, accumulator, high and low pressure switches 
were  
> replaced 4 months ago when the system was last recharged (and 
I'll  
> replace the accumulator and orifice tube again when I open it up 
to  
> replace whatever is leaking).  As far as I know, everything was  
> working and the compressor was cycling normally the last time 
around,  
> therefore, I don't suspect faulty switches (I didn't have gauges  
> then, so I don't know the pressures).
> 
> Section N:09 of the good book seems to point to a faulty orifice  
> tube, clogged compressor inlet screen, or overcharging.  Given my  
> data, could that be right?  I tested the calibration of the tank  
> scale this morning, so I don't think I'm overcharged (especially  
> since I only put 2.0 pounds in).
> 
> Any advice on how to proceed would be greatly appreciated.
> 
> Thanks!
> Travis Graham
> #6344
>









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