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Compressor runs constantly

PDA1 on Wed May 20, 2009 2:38 PM User is offline

Year: 96
Make: Ford
Model: Explorer
Engine Size: 4.0
Refrigerant Type: 134a
Ambient Temp: 77
Pressure Low: 30
Pressure High: 160

My a/c compressor runs constantly now that I put in the total amount of 134a (26oz)....maybe there's just a bit more (I have no way of measuring the amount put in but I know it's over 24oz. (by way of back ground- I R&R the compressor, dryer, orifice and flushed the system yesterday).

Yesterday, when there was about 24oz in, with an ambient temperature of 65, the compressor cycled off and on every 8 secs. or so. Pressures were, I think, 145/25.

Should I expect the compressor to be running constantly now?

If not.....how can I fix it?

Thanks.

Chick on Wed May 20, 2009 3:43 PM User is offlineView users profile

The warmer it is, the less it will cycle.. Is it cooling? check the pressures wehen it's 80+ degrees Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

PDA1 on Wed May 20, 2009 3:56 PM User is offline

It doesn't cycle off at all.

The ambient temperature is now about 80. Low humidity....if that matters.

Yes, it's cooling well. But, my hand isn't freezing in front of the vents. I haven't measured the vent temperature yet but it's cool (but not freeze-you-to-the-bone). By "cool" I mean that if it was 90 out.....I'd be a little concerned that the a/c might not keep me comfortable enough. That's just my opinion about the vent temperature.

As I said, yesterday it was cycling off and on quite nicely about every 8 to 10 seconds with an outside temperature of around 65 (I think that's what it was) There really was just a little less 134a than 24ozs. My system calls for 1Lb 14oz (which I interpret as 30oz).

Hope that helps explain my situation a little more.

Thanks for the help.

bohica2xo on Wed May 20, 2009 4:18 PM User is offline

Raise the engine RPM to above 1500 with the cabin fan on low. It should cycle occasionally.

Cycling is an indication of either undercharge, or excess cooling capacity. Systems may not cycle depending on load & condition.

Do a full load test. Doors open, cabin fan on highest speed. Run the engine above 1500 RPM for 5 minutes, and record the high & low side pressures while the engine is still running above 1500. Post the results.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Chick on Wed May 20, 2009 4:19 PM User is offlineView users profile

To start with, you need to have the correct amount in the system, if you are low, add more til you have the correct amount. You can damage the compressor running it low... Also, feel the inlet and outlet of the evaporator, should be the same temp, with the outlet (suction side) a little colder.. If that is warmer, you are undercharged.. Hope this helps..

-------------------------
Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

PDA1 on Wed May 20, 2009 7:44 PM User is offline

Alright, here are the latest readings, do they appear to be good?

1rst situation......

Ambient temperature- 72
Center dashboard vent temperature- between 39 and 41
Windows all open
A/C switch on MAX AC
Vent fan speed- on the 2nd dot (that is- low speed)
Pressures- 175/20 (compressor off)
80/45 (compressor on)

2nd Situation.......

Engine RPM- 1500
Vent fan speed- full speed
A/C switch on MAX AC
Center dashboard vent temperature- between 41 and 42
Windows all closed
Pressures- 175/25 (compressor off)
80/45 (compressor on)



3rd situation-

Same as in "2nd situation" except A/C switch on AC (not MAX AC) and......
Pressures- 200/30 (compressor off)....I pretty sure of the Low side number. Seems strange doesn't it?
80/45 (compressor on)


Thanks fellas.

Edited: Wed May 20, 2009 at 7:46 PM by PDA1

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