A/C Question

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May 7, 2013 | 07:20 PM

WRABER

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A/C Question

Decided to service the A/C in my 2006 F350 today, before I leave out again on a trip. It's been cooling, but seemed like it could do better. Warmed it up and hooked up the guages. Ambient temp 70 F. and what seemed to me like excessive sweating on the lines around the accumulator and in to the evaporator. Starting head pressure 150 and suction 20. Added 1/2 -3/4 lb 134a. which brought the head pressure up to 250 and the suction to 30. Guages steady with no abnormal fluctuations. Temp reading at the vent now 40 degrees. Road test seems like it's cooling much better. Compressor is cycling and everything appears to be working properly, but there is still a lot of sweating at the accumulator and the line in to the evaporator as opposed to frost. Now I'm beginning to wonder if I have a themostat issue that's causing the compressor to cycle off to quickly. Any comments anyone??

May 8, 2013 | 05:57 AM

projectSHO89

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From: St Louis

Sweating is due to your local humidity level. Unless it freezes and makes frost, it is normal.

May 12, 2013 | 08:14 AM

WRABER

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A/c still not cooling like it should. If I set it on manual it cools but not cold. If I set it on automatic it seems to do better on cooling. Still believe the compressor is cycling off to quick.

May 12, 2013 | 02:32 PM

projectSHO89

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From: St Louis

Rate of clutch cycling is dependent on load, ambient conditions, and charge level. Unless you KNOW what the rate of cycling should be, then you're just guessing.

There are plenty of possibilities for insufficient cooling including improper charge level.

Jun 4, 2013 | 04:29 PM

WRABER

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Bought the Ford service manuals on DVD for the truck. Did a self test on the climate control module, no active codes, checked for saved codes and none there. Current ambient temperature of 90, fan in front of radiator, system stable with windows open. According to the Ford TSB charts I'm still a little low on refrigerant. The low side range is 42-62 psi. I'm currently at 40 psi. High side range is 180-300 psi. I'm currently at about 225 psi. This is after adding 12 oz of refrigerant. Inside at the vent is 59 degrees, cool but not cold. Sweating on the evaporator line has decreased. Need to run to the store for more refrigerant, but I believe I'll try the addition of some more to bring the the low side up to 48-50 psi and the high side no more than 275, then see how it does. If that doesn't work then it's evacuate, disassemble, flush and start over. The system was opened in March (by Ford) when the head gaskets were replaced, so there is a possiblity that there might be so contamination issues.

Jun 9, 2013 | 08:35 AM

WRABER

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Added more refrigerant and brought the suction side up to just barely within the chart limits. High side in the middle of the chart limit. Windows open, ambient temp 85, temp at the inside center vent 48. Still believe that it's capable of doing better, any comments???