Want to know operating pressures on a 134a refrigerator low and high
Maximum efficiency is achieved when there is the greatest difference between high side and low side provided the low side stays under 30 psi or so. The low side pressures must stay low enough to cause the refrigerant to change states in the evaporator. If you see frost on the compressor suction line, there's too much refrigerant, and you'll overload the compressor. The correct approach, if you have the equipment and it sounds like you must have a gauge set but you need recovery to do this right, is to evacuate the sealed system, (a tight system will hold a vacuum overnight, but an hour is a good test if you suspect any leaks) and refill with the exact amount of refrigerant (by weight) as indicated on the ID tag.. Any system that will not perform when filled to that specification has either a bad valve in the compressor, or a restriction caused by contamination. Contamination is usually from moisture (humidity) introduced into the system by improper servicing, but is usually relieved if the system is under vacuum long enough to boil out the moisture. If the compressor is the culprit, it's usually game-over.
May 30, 2009 |