the low pressure switch is bad or you have a blockage in the system like the orifice tube
To add Freon to a 1994 Volvo 850 you will need to buy 4 cans of Arctic Ice and one can of blue dye. Use the spray can nozzle to attach to the air conditioning compressor and add the Freon. I am a certified auto AC tech and would not recommend putting 4 cans of Freon in a car AC system all at once. If you do not have gauges then put one can of Freon (refrigerant) in at a time. Have the air conditioner turned up on high, the car running and begin adding the Freon while shaking the can. When the compressor kicks on ( you should hear the compressor click on) you should almost be finished. If the compressor cycles in and out quickly this means you need more Freon. If the compressor clicks on and runs for a minute or 2 then put no more Freon in the system.
Oil starvation is one possibility. The refrigerant is what transports the compressor oil through the system - an insufficient amount of refrigerant won't properly transport the oil, and it'll starve the compressor of lubricating oil. And insufficient amount of compressor oil in the first place could also be a cause, especially if you're charging a dry system. If you did add oil, did you spill any on the compressor? Because I've seen that cause what you're describing, as well.
If the A/C system is empty the compressor will not turn until you get enough refrigerant in it. Just turn on the A/C and hook up your can of freon. Once the freon starts filling the system the A/C clutch will engage.
If the compressor is running, the blower is blowing, and there's no cold air, you need freon. If the whining is from under the hood, the compressor may be damaged. That's what happens when running without freon.
Shops use a freon recovery system that contains the freon while the system gets worked on. The system has to be cleaned and vaccumed properly to remove trash and moisture or it will fail again or even not function properly.
Yes, in order for the compressor to take on the new coolant and oil charge the compressor ideally should be running. It is posiible to begin charging the system with freon prior to compressor initiation, however to get an accurate reading of the pressure in the system the compressor should be cycling with differential valve operating properly. If it is clogged or the compressor is not cycling then then low side reading will give an elevated pressure while charging the system. Does that make sense?
Remove some freon. You might have overfilled it. Run car with a/c on while removing it, you will hear compressor kick on and off while removing it (stay on more as you get closer to where it needs to be). Eventually it will stay on and the air will stay cold, check with gauge while performing this task. You can use one that comes with the cans @ auto zone or other parts stores!
most likely low on freon. while driving the ac compressor spins faster so it might cool better with low freon at higher engine rpm. have your system charged and checked for leaks.
A bad compressor belt can cause a whistling noise while running the air conditioner. A bad engine can also cause this noise.
This is not the cause, this relay is to start the and run the compressor (Basically) and it will not cause the system to lower overnight.
Because of today's EPA regulations, you might be required to use a freon reclamation unit. Most certified HVAC technicians have that type of equipment on their vans. You should also check EPA regulations in regard to freon and refrigeration, and especially if it's an older unit that uses freon 22. If you release the freon and get caught, you could possibly face a heavy fine.
Generally this is the result of either the compressor not running (just the fan is running) or, more commonly, the freon level is low due to a leak in the sealed system, so the compressor runs but is not able to cool. You can usually hear the sound of the compressor starting if there is low freon, while there will be just the sound of the fan but no deeper 'growl' of the compressor when there are any other problems. It is usually not cost effective in small relatively inexpensive window air conditioners to have someone fix either of these problems due to high labor costs, replacement of the entire unit is recommended.