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Goodman 410 Problem

I have a situation with a goodman 2 ton-410 unit--first was given wrong txv--installed new txv- getting high head pressures, unit goes out on high pressure. I can run the unit with the bulb off the suction line, but have 8 degree superheat, and 26 degree sub-cooling-with bulb off of the suction line. When I put the bulb back on the suction line it takes about a minute to over pressure. Noticed 4 degree difference across filter dryer. It was 78 degree day and I was running 375 psi on high side, and a 50 degree coil. Could this unit be overcharged-did not weigh charge. Could it possibly be a blocked filter dryer that when the txv bulb is in ambient air and open it will run but when it starts to meter there's either a blockage or the bad luck of a bad txv. Also tried to shock txv with hot then cold water no change.


  • Tom Blackwell_2Tom Blackwell_2 Member Posts: 126

    Sounds like an overcharge condition. When the TXV goes full open some of the charge is in the evaporator, thus reducing the overcharge in the condenser. The best way on these small systems is to weigh in the charge.
  • don_9don_9 Member Posts: 395
    Expansion valve

    I will say that we have had many problem with txv the past couple of years.Was on one yesterday that fail shut.I could only assume the bulb lost it charge however no signs of that.

    You have a temp drop across the drier of 4 degree.They say no more then 3 degree and it time to change them.however alot time its been my experience that not true and the correct way is to have some pressure tap before and after.Also make you question why they are on a suction drier and not on a liquid line drier.

    I agree with with everyone else sounds overcharge.when you have a txv its always best to charge by subcooling will help keep from overcharging.But you have to be paintence and watch your readings.not hard to overcharge one when you are dumping liquid in them and not a gas..Require you to add alittle and watch the numbers.

    Good luck.
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