AC Compressor Replaced Then System Freezes Up?

[Jim Conway]

Hi, My in-laws had an exterior AC compressor replaced (by an HD sub- contractor FWIW...) which worked for a few days, and then ceased working when a coil leak froze up at the blower (as diagnosed by the same HD sub-contractor who they called back). He explained that the problem at the blower was pre-existing, and had nothing to do with his original compressor replacement. He's attempting to locate a replacement coil for the single defective coil, but estimated replacing all coils which could be necessary if he can't find a single coil and could cost upwards of $2K. After they just spent $3k having compressor replaced.

At the same time the new unit crapped out, they also developed a thermostat problem at a second unit they have in their attic. That problem has already been fixed by the same tech. Each unit is controlled by its own thermostat, but I'm not sure if both systems could somehow tie together....

I find the timing of both problems suspect (though not unlikely), and am wondering if they are being sold a bill of goods. Feedback appreciated!

[Moe Jones]

What caused the original compressor go bad? When you are replacing the compressor you can some what get an idea there is a leak in the system by the amount of refrigerant that is left in the system. Now allot of the times after you get the new compressor back on line you then might be able to see what caused the compressor go bad. Is their system really old? If so they may want to replace the evaporator coil and furnace at the same time. It is generally cheaper to replace both at the same time. If they replace the evaporator coil you might install a low & high pressure switch and time delay incase of any further problems that may occur in the future. These devices will shut down the system if they detect low or high refrigerant pressures.

[Jim Conway]

They were dissatisfied with the temp, and previously had the old compressor recharged. Conceivably then, from what you've stated, a more robust newer compressor might cause something to exhibit (i.e a coil leak) that a weaker one may not have. The house/system is ~ 9-10 years old.

[Rod]

Not exactly. If a compressor isn't working you can't really tell anything else about the refrigerant circuit until you get a working compressor in it. Kind of like a car with bad brakes and a blown motor. It's hard to tell if the brakes are OK if you don't have a motor that will move the car. A lot of times when you change a compressor other problems will show themselves simply because you have a compressor that is moving refrigerant through the system and you can watch the pressures with your gauges. Never seen a coil cost more that a $1000 replaced in this part of the country (GA). Sounds high too me. Also most of the residential compressor changeouts we do run between 900 to 1700 depending on the tonnage of the unit. Again sounds high. If I charged customers like that I could take a really good vacation every year but then comes the problem of having to be able to sleep at night. Rodney R & S Heating and Air