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i have a f-350 2002 and the a/c compresser runs all the time and it only blows at 52 degrees.I was wondering why the compresser is always running.I dicharged the system and recharged it,didnt help any.I checked the high presure and low pressure and everything is good.Cant figure it out,any help would be great.
Do you have auto climate control? I have similar problems when the external temp indicator reads low -- it sporadically reads in error and then after a day or two, reads correctly. Today, the exterior temp showed 69 degrees (it was 95) and with the AC temp set at 60 (the lowest), I got temps in the mid 50's from the vents. This afternoon, the temp gage read correctly and the vent temps dropped to a nice 41.
Base on what I see, when the external temp reads less than 15 or 20 degrees above the internal setting, the AC gets proportionately warmer (I think the heater door is opened slightly). Now if we could figure out why the external sensor is out of whack (it has been replaced twice and the control unit replaced once).
I recently posted the readings I was picking up at 103 degree outside temp: 46-48 degree a/c output. But this is in very low humidity of 13-14%. It seems, the higher the humidity, the higher the output temps...
i do not have digital controls,all manual controls.The compresser works in every postion,but not off.As far as i remember it always worked in every postion.I put the recharge gage on it,was reading 35-40 pounds of pressure on the low side.Didnt check the high side.The system does not run on vac,its all electronics.I have checked both high and low pressure swithes,they work.Today i was driving it,coming home from work and going down hill the a/c got really cool,like 45 degrees.But going up hill the temp went up to 65.I also checked my a/c verses my friends truck,same thing just 1 year newer.His temp at a high idle of 1200 rpms and his a/c was putting out 42 degrees.Mine put out 59 degrees.His compresser was cycling on and off,mine stayed running.
"Aren't these things "fixed orifice" which means the compressor is cycled on and off at a set interval?"..A fixed orifice refers to the freon metering device..Do these trucks have the fixed orifice or a TXV?..
"His compresser was cycling on and off"..Most likely because it reached temps required to cause it to cycle on and off, unlike yours..Your pressure sounds a little low, did you compare your pressure with your friends?..JMO but you sound low on freon but without actually working on it I am guessing..
[QUOTE=krewat]Aren't these things "fixed orifice" which means the compressor is cycled on and off at a set interval?
If it's not cycling, I'd look at whatever electronics controls this.[/QUOTE]
I do believe they use a flow rate metering device, the compressor should run the whloe time the A/C is on unless the evaporater temp is low enough to drop the suction pressure below the low pressure cut off, chances are if your compressor is cycling when the fan is on high, it is low on refrigerant.