Pete 379 air conditioning

First video that popped up when i googled ac recovery machine. He points right to the oil recovery tank and says what it is. But ya, no ac machine could possibly suck oil out of the system. Right? That oil recovery tank can't possibly be collecting the oil from the system could it?!

 

That machine is pulling out the freon which is mixed with the oil, it then filters out the oil that is traveling in the freon; like every other A/C machine.

That recovery process is NOT vacuuming and it does NOT remove all of the oil, just what is caught in the freon; all freon leaks also deplete the oil charge for the same reason but to get the system back to the CORRECT oil charge AND the correct freon charge requires flushing to remove the oil that did not escape with the freon.

That machine ALSO has a built in vacuum pump, that step occurs AFTER the freon has been removed and AFTER the flushing and component repair has occurred and AFTER the new oil has been added back into the system; the LAST step before recharging with freon is vacuuming the system and this does not remove ANY of the new oil and dye which was added BEFORE the system was reassembled with the new parts.

Vacuum pumps do not remove oil, or dye, or any contaminates; the vacuum process ONLY boils the moisture into a vapor so it can be sucked out of the system before the freon charge goes back in.

Any vacuum pump that reaches the proper vacuum will do the job adequately and any process that evacuates the freon will remove the same amount of oil. The only difference between the machine and just cracking the line and letting it go is the machine captures and filters the freon so it can be reused, a certain amount of the system oil will leave with the freon either way.

 

So which is it? No machine can remove oil from the system or the machine will remove oil from the system? You are saying opposite things. First you tell me that oil is removed with the Freon, then you call me a liar and say no shop machine could have possibly removed oil from my system, and now you are saying a vacuum pump will remove oil from the system.

 

No machine removes oil, the freon will bring some of the oil with it when it is evacuated but only flushing a system will remove all the oil and other contaminates.

This whole debate began because you said it was not true that the oil circulates with the freon in an A/C system; you said it was wrong to think that oil leaks out with freon or needs replenishment when a major component is replaced. I have done my best to educate you on this subject but it seems as if it was a colossal waste of time so I am good with whatever you want to believe about mobile air conditioning design and maintenance.

 

I never said oil doesn't circulate with the Freon, i said adding 2 ounces of oil every time you open the system will over fill the system with oil.

 

Ok, how does this look. 90 degrees fan on manual

 

I have noticed with the fan off pressure rises quickly on the high side engaging the fan (idle only) appx every 30 seconds. Is it just too much heat to dissipate with no airflow over the condenser.

What actually happens in the condenser to the freon that causes pressure changes.

 

Nobody in this thread said to add 2 ounces of oil every time you open the system, I said a common rule of thumb when replacing any major component like a condenser or evaporator was 2 ounces of oil to replenish what was lost; this is common practice and gets you close enough to protect the compressor.

I also said the only way to be certain that the oil charge is optimum is to remove ALL the oil by flushing the entire system and starting over; if a system has been leaking and recharged as a band aid for awhile or has been serviced by someone who does not know what they are doing then an A/C tech will always do a complete flush after repairing whatever was wrong.

 

That is normal, freon is a gas that cools when it's pressure is reduced rapidly and heats up when it's pressure rises rapidly.

So your compressor pumps the freon first into your condenser which has small orifices, this raises the pressure of the freon.
Then the high pressure freon passes through the dryer/accumulator to trap any moisture that may be in the freon.

Then the high pressure freon passes through the expansion valve (or orifice tube on some systems), this is a valve that has a much larger exit hole than entrance hole so the freon drops in pressure very quickly; making the freon get very cold.

This cold freon then passes through a small radiator inside your cab (called an accumulator) which has a fan blowing the hot air from your cab through the fins on the accumulator. This removes the heat from your cab air and sends the cooled air back into the cab through the A/C vents.

Now the low pressure freon leaves the accumulator and returns to the compressor to be pumped back up in pressure and do it all over again.

This system must be controlled so the high side pressures don't get too high and blow something apart or too low and starve the compressor for freon and oil (this happens when the accumulator freezes up)

The way the pressures are controlled is 2 fold, by using the engine fan and by cutting power to the compressor.

When the high side pressure reaches its maximum safe level the A/C will engage the engine fan, this cools the freon slightly which reduces the pressure and protects the system; if the engine fan cannot reduce the pressure enough to achieve a lower psi the A/C system will cut power to the compressor until the pressure returns to a safe level.

If the low side pressure drops too low (loss of freon or freeze up) the low pressure switch will also cut power to the compressor; if the problem was a freeze up the low side pressure will rise again when the accumulator thaws and the system will resume normally, if the problem was freon loss the compressor will not start again until the freon charge is replenished.

 

All is normal now. Yes with that temp the high side wise that quickly with the fan in automatic mode. Your system is fine and here is the chart with ambient temps