Isuzu Repair: 94 isuzu air 3.2 trooper, ambient air temperature, expansion valve

Question
QUESTION: Hello Daniel, i have added gas to the air condtioner to keep the comp from clicking on and off. the high side is 325lbs  and the low side is about 30. it is cooling ok and the comp rarely cuts off now. is the high side to high. what pressure should this system run on. do you think the filter on the condensor is partly restricted. Thanks Don

ANSWER: Well Don does the evaporator ever try to freeze over?? The expansion valve/ orifice tube could be clogged causing the system to have excessive pressure. I would have it serviced and leak tested as well. The filter on the condensor is actually the receiver drier. It catches any water/moisture that could be in the system using a small dessicant bag.

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QUESTION: the expansion valve was replaced a few days ago and there was no improvement, what pressure should be on the high side. thanks don

Answer
Well most people do not realize is that to do a proper cleaning of an A/C system you need cleaning solution(at least two cans and they run about 20.00 a piece). A new receiver/drier. An expansion valve(the expansion valves on some models is actually inside the evaporator) and a new condensor or have it flushed with a pressurized system as well as pressure flush all of the A/C lines as well. A piece of trash smaller than a pin-head will clog that expansion valve, which will result with too much pressure on the high-side, and it will quite blowing cold air for a second. Then the crud will get dislodged and it will then start to blow cold air. Also the diference in the ambient air temperature and surroundings determine what pressure is actually present on the high side so I would be lying to you if I said "this is exactly what it should be" because I can't give you a 100% positive it would be right. The only advice is to have it looked at and it really should not cost that much to have it serviced. Maybe 100.00, maybe. I hope this helped you and in the mean time I will dig a little in my books and see if I can't find something okay? Thank you for your patience and my apology I could not help you more Don.