I have a Goodman 3.5Ton outdoor unit still available. It's been left with lines unattached to an evaporator coil and without freon for the past year and do not exactly know what to expect of it's condition.
To save some dollars I'd like to be able to reuse it in the new house for another year or two if possible.
The upstairs is 4Ton and the downstairs rec area is 2.5 ton. I'd like to buy only one outdoor unit for now but prefer to use the new outdoor unit for the upstairs where we spend the majority of our time.
It's hard to say if the unit is good or not, with no refrigerant in the system. If the system had had refrigerant in it, you could have pumped it down and checked the pressures as it approched 0 psig. on the low side (suction side). If, you where able to achieve a pull to below 0 psig. into a vaccum,(provided the compressor is a reciporcating type and not a scroll) than I would say that the compressor in the unit was still ok. This uaually gives an indication that the reed valves or ok and unit is capable of operating ok. No guarantees. Was the unit working ok at the time it was stop being used. Why is there no refrigerant still in the system? Do you know if the refrigerant was recovered or it leaked out. I have changed out several condenser units due to hail damage to the fins of the condenser coil. These were insurnace claims. In the process of revomal and installing a new unit I observered that the compressor was working fine, by checking my gauges and the pressures that were presneted at the time of removal. In fact the first unit that I had done was a Janitrol/Goodman, 3 ton. It had about 6 to 7 years of use on it. Being in the need for a new unit, but didn't want to buy at the time,(I was in the process of adding on to my house,myself, and doubling the size,I was waiting to finish and install a new 92+ Afue furnace/14 seer system),I installed the damaged unit,combed the fins,installed new liquid filter,and ran it for six more years before finishing my home and installing a new system. So, it can be done, but its the old saying "buyer beware". If you change it out yourself no great loss, except time and a little expense. If you have a contractor do it, there will surely be no guarantees and pretty nice service fee.
The furnace and evaporator coil were damaged in a fire and removed along with the debri. Now that the house is restored, I still have the outdoor unit.
The unit more closely matches the upstairs load but is a little undersized with the addition we added on. I'd also rather get a higher SEER model for the upstairs since that's where the heat goes and where we spend the majority of our time.
The concern is if I use it for downstairs it's oversized by at least a ton. Can I use a 2.5 ton coil with this 3.5 ton condensor with a TXV or something else that would allow it to work reasonably (9 SEER maybe) for a year or two?
It would be a pity to set this condenser in place, weld everything up, pull a good evac, weigh in the charge, only to go hit the disconnect and the compressor is dead meat.
Has this unit sat with no refrigerant and open to the atmosphere? If so, chances are good the insides are loaded with moisture. Compressor oil is hydroscopic (mineral not as bad as POE but still it'll grab at water). Also, when inside unit suffered fire, did it open system to contaminants from fire? When the indoor unit was removed, did they just cut the lines (sunshine recovery) and haul it off, leaving the lineset open?
At worst, if the compressor still runs, you may be faced with a considerable cleanup effort to ensure this thing doesn't die before you can buy your new condenser. And then you'd want to be sure the system was once again cleaned (in addition to a good evac) when you go to change out the condenser again.
You can undersize indoor coil but I wouldn't think of it without a TXV.
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.
probably would have to cut compressor out& drain oil out & replace with new oil.Pull a good vac& put on suction dryer & liquid line filter too.I personal think u should think about the options.
Maybe get another cheap Goodman outdoor for the 2.5 ton and go with matched components at 12SEER.