I just moved into a new home, and the A/C unit isn't working. I have some information about my system... There are issues with the A/C unit that aren't related to the unit itself (such as who is at fault for it breaking, and who is responsible to pay for it to be fixed) - but those issues are for another forum, I'm just interested in understanding how to diagnose / figure out what is wrong, and figure out what needs to be done to get it working again.
The A/C unit and it's "issues"
When we were under contract, apparently something caused the A/C unit to be blowing constantly. We were never over there, but the story we heard was that the previous owner's wife went back there to get something (they moved out and it was vacant for about a month) and it was really cold in the house. I heard that when he went back over, and had to get something worked on.
From the seller's realtor, we learned something about how the a/c unit was "iced over" and that he had to pay $350 in electrical bills... later on I heard that the $350 was for a service call - so I don't know what exactly happened, or what was going on.
When we asked him to ask the previous owner about who serviced it when we noticed it wasn't working shortly after we moved in (clearly, whoever serviced it didn't fix it), we learned that he just "had a friend come over" to look at it. Who knows what the friend did... likely nothing...
The unit itself
The unit is a Rheem unit - model RAMB-036JAZ
serial number 6263F170109566
(on the unit it mentions it was installed in 2001).
- When the A/C is turned on at the thermostat, the fan in the compressor doesn't spin
- On the side of the compressor, there is a button labeled "high pressure reset" - this button appears to be damaged (the little rubber cap for it is ripped off) and appears to be permanently in the pressed state (trying to push it in just for the hell of it, I realized the button was already pushed in)
An HVAC technician took a look at the unit
We have a home warranty, which covers the A/C unit. A service person the home warranty company has do contract work came out and looked at the unit, and told us the compressor is blown. His opinion is that the compressor is blown and that the warranty company would likely not cover it because it was caused by lack of maintenance (which, imho, is a BS excuse - since just about any problem could be classified as a "lack of maintenance" depending on how broadly you define maintenance)
I'm not sure I trust this guy, and here is why:
- He told my wife that he thought our unit was undersized. He told us that we had a 2 ton unit and need a 4 ton unit (using a rule of thumb) for our 2000 sq. foot split level home. (Our unit is, in fact, a 3 ton unit - which I was able to easily determine based on the Rheem product number - so he obviously doesn't deal with Rheem at all)
My wife claimed he sounded like he knew his stuff, so I'm guessing he wasn't a complete idiot. All he really told her, however, was that it was "blown" and that his company would be happy to provide a quote if we wanted to replace it with the 4 ton unit. He did say he would contact the warranty company to see if they would cover the repairs. (He never mentioned anything about any upgrades to ductwork that would be involved in such a replacement, and made it sound like a magic "replace the box and the system works better" kind of upgrade)
What is likely the problem, and what will likely need to be done to get it fixed?
Is there any chance the parts are covered under warranty? From my research, I see that the "Scroll Compressor" has a 10 year limited warranty, and everything else has a 5 year warranty. I'm guessing this guy having his "friend" do something to it may have voided the warranty, and the "Scroll compressor" may not even be the problem.
I have found that I can buy an entire replacement unit for the outside compressor online and have it shipped to my house (obviously I would have it installed by a pro). Is it generally easier to repair a bad compressor or just replace it when you factor in labor and parts?
I do plan to do an HVAC load calc on my house to verify that a 3 ton unit will adequately cool my house - since I'm in a very dry climate (Utah) I wonder if the person installing the previous unit thought enough to look at just the sensible numbers... or if they just looked at the total numbers. If I do end up having to replace it, I want to be damned sure that the replacement is the right size.
Other interesting information
The house was built in 1999, but this A/C unit was installed 2 years later. I have no idea why they would need to replace an AC unit after only 2 years, but should I look at other areas of the house to make sure that there isn't something that would cause units to burn out prematurely? (such as wrong size unit, ducting... etc.?)