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My 24 year old home A\C went out some time Sunday morning. I had a tech come out and look at it, and was told that the compressor is shorted to ground, and that this means I have to replace the entire compressor and possibly the entire system.

I'm asking this community for a sanity check, since I know nothing about HVAC systems. Is a "compressor shorted to ground" really a "replace the whole kit and kaboodle" situation? Or is more information needed to reach that conclusion?

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They want to replace the entire system - inside and out. –  John Jun 11 '13 at 12:08
    
24 years - it's the original system put in when the townhome was built in 1989. So yes, I've known a full system replacement was coming, I was just hoping to squeak out a few more years before it got here... –  John Jun 11 '13 at 12:39
    
The time has come, but don't feel so bad. You'll probably end up with a more efficient system, which will save you a bit in operating costs. –  Tester101 Jun 11 '13 at 12:51
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Just to answer your literal question, compressors are not field serviceable. If your compressor has a problem, the only option is to replace it. –  longneck Jun 11 '13 at 14:40
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Final result: the compressor is just fine. The first tech didn't bother to examine the whip, which was shorted phase-to-phase just as it exited the disconnect box. Roughly $350 later, everything is back in working order. (Yes, I'm still planning on a complete replacement in the next 3-5 years.) –  John Jun 12 '13 at 11:12

1 Answer 1

The compressor is the "engine" of the AC system. It, and a few valves, and the condenser fan, comprise all the active portions. Everything else is passive. The compressor is an electrical motor connected to a precision pump. The pump has to be lubricated by sufficient refrigerant (Freon or substitutes). If a compressor seizes, it may burn out the electrical motor, causing the electrical windings to short out.

Long story short, a failed compressor may be a reason for system replacement. You would be well advised to get a second opinion from another contractor. Get quotes for both repair and replacement.

Another reason to replace the system, is the mandated phase-out of R22 refrigerant. If your system is older than 5 years, it probably uses R22. While an existing unit doesn't need to be replaced, per se, because of the phase out, practically, it will, due to the price of the refrigerant. I just paid $5/ounce for my system recharge.

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It's 24 years old, and yes it does use that horrendously expensive R22 refrigerant. I'm not looking forward to paying $11k (the first quote of at least 3 I'll be getting) for a new 3 ton system... –  John Jun 11 '13 at 12:10
    
At that price, you may want to look at a geothermal heat pump (with ground sourcing). The install costs are high, but operating costs are usually much lower. Look here: qualitysmith.com/request/articles/articles-hvac/… –  HerrBag Jun 11 '13 at 12:28
    
Geothermal probably isn't a viable option for me since I'm in a townhome, not a single-family. The HOA might not like that idea. –  John Jun 11 '13 at 12:43
    
In that case, pitch it as a high efficiency upgrade for all the units. Common wells are possible, though not universally acclaimed over individual wells. You'd need an experienced contractor/HVAC design firm to make the pitch/proposal. Joint system maintenance would get rolled into the annual maintenance fee. Just sayin... –  HerrBag Jun 11 '13 at 13:04

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