you need to get a gauge set hooked up to the high and low pressure lines to tell what is going on. color doesnt tell anything, you need pressures.

if it was low on freon the low pressure switch should keep the compressor from running. sounds like the compressor valves are shot. compressor running but not pumping.

 

He said...but the pressure is where it should be..

That would tell me he put a gauge on it and it has a charge on it.

 

Sorry about that I read your first post that said the pipes by the "condenser" weren't cold, and they shouldn't be cold they should be hot. You really need to see both the Hi and lo sides to determine what is going on but it could be something as simple as just low on freon, not low enough to trip the LP sw but low enough to not cool.

 

well ive put my gauge on it today. and my gauge is busted. someone sat on it.. and by someone i mean my other truck. so heading into town to borrow my friends gague set that does high/low and will report more when i return

 

ok finallly got the gauge hooked up and we are looking at 45 on the low and 70 on the high. now i know that the 70 is way low. what could be causing this and how would i go about fixing.

 

compressor.its been many years since i did a/c work.



with a 45 psig reading on the low side it will not open the low pressure switch to cycle the compressor off.your evap is 50* with that pressure.

70psig on the high side tells me that it is not pumping enough.your condensor is around 70* at that pressure.it has to reach 86* to condense back to a liquid.which would be around 96.6 psig

according to my basic a/c service training manual it says compressor malfunction. depending on what system it is, it may have a EPR (evaporator pressure regulator)stuck in the compressor.

hope this helps.

 

also have the fan on high cool and engine revved up when you take the guage readings.do not take them at idle. it will give false readings.

 

if it did'nt have a charge or a low charge the low pressure switch would keep the compressor from engageing.

evidently the pressures are not where they should be. pressures are a starting point to troubleshooting along with temperatures.
the cycle of refrigerent is not complicated but it has to have the correct pressure/temp to work.

Just for some folks on here that is not sure, i'll give a short course.

refrigerent is compressed and condenses to a liquid and enters the condensor, it leaves the condensor subcooled. it enters the metering device and is restricted to a degree. that lowers the pressure when it leaves and enters the evaporator where it changes to a vapor (liquid refrigerant boiling as it absorbs heat.) and absorbes heat from the warm air being blown across the evaporator.

It is now superheated and should be completely vapor leaving the evaporator. from the evap it repeates the cycle and enters the compressor. you just remove heat and put it somewhere else, preferably outside.

condensation is just the moisture in the air condensing on the cooled evaporator.just like a ice cold glass will sweat, it is just the humidity condensing on the glass.

not trying to be smart, just wanted to give some folks a glimpse of how it works.

most of my work was residental a/c and some commercial. not really up on any of it now. just wanted to try and help troubleshhot.

 

yes i undertand how to take the reading. this was at around 1500 rpm and taken after 10 min. so are we looking at needing a new compressor??? i am leaving for this trip sunday of next week so i do have some time to work on this a bit. anyone else think that this is what i sould do, not doubting anyone opinion just dont want to spend the $125 if i dont need to.

 

I second the compressor vote. Orfice tube could be plugged, but even if thats the issue you still will need a compressor now or soon..

Jason

 

10-4 well i guess its on to the compressor search. i will report back when i get the part and install it.