I have an american standard 13 seer 3 ton heat pump.The house is 1800 Sqft The out door unit and indoor unit are a matched set. The guy who installed it has been back four times. Since then I have been doing a ton or research and asking him questions. Well frist off the unit is not cooling properly. So he came back and the he said the unit was under charged. The subcooling should be set to 10. Well he set it to 33 because he charged it using super heat the frist time and set the super heat to 10. Well he came back and now recoverd the freon and set the subcooling to 14 and did not ceck the super heat. Well two weeks later it got up to 96 out side and the unit could not keep up. The house got up to 76 and ran all day there was a 10 degree split 63 out 73 in.
Well he came back out and spent about three hours at my house. He set the subcooling to 10 but he said the super heat should be about 8 to 13 well it was 20 then settled at 18. He went to the air handler and disconnected the TXV. The super heat then came down to 2 so he said that was working. When he was checking the temps coming out of the vents it was 72 going in 60 coming out. He then charged it back to 33 subcooling 77 punds of suction and the temps came down and super heat came down to 11. Well its cooling not very well it has to run all the time to keep the house at 75. now the temps are 55 out at night 70 in. I had a three ton carrier 10 seer it keep this house cold and ran half as long as this one does. So can any one tell me whats the deal do I have a lemon unit? Is the TXV valve bad could there be contamination in the system?