I purchased this house 1 yr ago, this system was installed 2 yrs ago. The outdoor unit is a Goodman SSZ140301AE, the air handler is a Goodman AEPF313716AA. There were a number of installation issues which have since been resolved (DIP switches misconfigured, jumper wire left in place, low voltage connections (thermostat wire, input on fan control board, and output on fan control board all connected with a wire nut for several of the connections), the 30 amp disconnect breaker on the indoor unit (and connected heat strips) aren't wired into the panel, etc...
I had the unit serviced a year ago, the tech felt the gas line, decided the unit was low on refrigerant, and added two pounds of 410a. He seemed to be having a hard time adding refrigerant, and had to heat up his tank with hot water in my laundry tubs.
This winter I noticed the gas line was luke warm, and had another company come out to service the system. Per his notes, the hot gas line was 100 degrees, pressure on the low side was 108, pressure on the high side was 325. He weighed in 1 pound of refrigerant, and the gas line dropped a few degrees. He weighed in a second pound, and the temperature remained constant. After calling Goodman support, they suspected that the system had a leak and the refrigerant had become fractionated. The Goodman rep also mentioned that there was no information in the documentation that indicated the indoor and outdoor unit were a match.
The lineset was left over from the R22 system installed when the house was built in '84. The indoor unit sits 5' lower than the outdoor unit, and at some time an oil trap had been added to the gas line.
The service techs recommended we evacuate the system and weigh in a new charge of fresh 410a. I suggested they replace the lineset at this time, to eliminate the oil trap and to eliminate any leak that may be present from the old lineset. During the service they also removed, cleaned, and verified the piston was a proper match with the factory rep.
After this service, the gas line was 130 degrees (ambient conditions on both days of service were the same). I believe the techs did the best they could to get this system working; the next step would be to involve factory support, but since I am not the original purchaser there is no warranty on the system. The techs seem to think the system is as good as it can be, but the mismatched equipment is the reason for the low temperature on the gas line.
My present plan is to have the system checked prior to cooling system and the TXV adjusted at that time (with the rest of the installation issues, I doubt it is correct, but the ambient temperature was in the high 50's so I don't believe subcooling could be checked). If the pressures seem to indicate a loss of refrigerant, or the system fails to perform, I plan to replace a 2 yr old system, assuming that the mismatched equipment is the root cause of the problem.
Does anyone have any suggestions of things to check, or if the system is mismatched, in performing poorly, etc? With the two different service companies, I've spent $2k in repair bills in the year I've owne this property, and I think any additional repairs costs would be better spent towards a new, matched system.