Outside unit needs replacing

[neeleyb]

One of my two 1986 vintage Trane heat pumps has stopped heating and cooling. I think the compressor has finally kicked the bucket; it has been very noisy for the last few years. Now the cooling fan runs, but the compressor doesn't. I suppose it could just be low on freon, but I think the unit will likely have to be replaced (I'll have a service man check it out to be sure). It is a 2 ton unit, one of the old GE units with the Trane nameplate. The other unit continues to work like a charm.

My question is this. Is it possible to replace the outside unit and leave the existing air handler in place? I'm sure this isn't the best approach, but I don't plan on living in this house but a few more years and would like to avoid replacing the entire system unless absolutely necessary. I had the two air handlers serviced a couple of years ago (fan blades and duck work cleaned) and both units continue to operate well and are still quiet.

I would appreciate your well-informed advice. I'm trying to become a bit better informed before actually beginning my search for a local contractor to do the work.

[BaldLoonie]

http://hvac-talk.com/vbb/showthread.php?t=165828

Read the posts on the above link. It is not wise to replace just the outdoor unit.

[AACHP]

Is it "absolutely necessary" to replace the entire system -- NO! Look hard enough and you can find some hack to replace just the compressor and tell you it will work just fine for another 20 yrs. You may even get a couple years out of it before something else major lays down.

My advice -- I think you already know the correct answer.

[docholiday]

While they are replacing the indoor coil/air handler they may want to take a close look at the interconnecting piping as well. They may have used different line sizes back then too which may or may not need to be updated.

[exquid97]

no, can't just replace the outdoor coil, need to replace the indoor coil also. And once you see your energy bills drop you will want to "86" the other 86 as well.

[scooters45]

Here in Florida it's no longer legal to install an HVAC system (residential) that does not have an ARI number.
I read that as you can no longer just replace just the condenser or just the evaporator. I could be wrong and have been before.
I believe it was Ruud/Rheem that issued a white paper where their testing showed if a system is mis matched (say a 13 seer condenser 10 seer ahu) the real SEER was less than the lowest rated peice.

My advice is save some headaches, put a matched system in with its warranty and lower your utility bills.

[AcDOCnTRAINING]

I would strongly recommend to replace the complete system, I understand it is a great expense but not doing so will become an even greater one! Scotter has a point most new equipment build today come with compressor design to run at greater capacity. In heat mode that new condenser(outdoor unit) will be producing plenty of heat which means the refrigerant in the evap coil will be under very HIGH pressure, the old evaporator coil (indoor radiator) may not be in condition to handle that. The result will be Refrigerant leaks that will harm that new condenser. In cooling mode the old indoor unit evap coil (indoor radiator) may not match up correctly with new condenser, that may lead to flood back or liquid migration which will also damage the new unit. Save your self a lot of trouble, remember new systems manuf offer rebates, power company also give rebates, & IRS offer tax credits which all help make it more affordable. ALWAYS HIRE A LICENSED PROFESSIONAL OR YOU MAY END UP PAYING FOR THE SAME WORK TWICE! good luck