Thoughts from anyone who knows HVAC systems

[Bugdog67]

I live in a modest home in coastal South Carolina, the heat/humidity capital of the world. I've been in my home for 19 years. The original HVAC system was 15 years old when I moved in and lasted another 5. Current system was installed 14 years ago and has been nearly trouble-free. We have an annual maintenance agreement with the company that installed it, which changed hands 7-8 years ago. For at least 5 years they've been telling me that I should get a new system for reliability, energy savings, yadda yadda. My philosophy is if it ain't broke don't fix it.

Two weeks ago a new guy with the company came out to do the semi-annual maintenance visit. He says that the unit is fine, and proceeds to tell my wife (I wasn't there) that the company will tell us that we should replace the system, but not to pay any attention because it's working great and everything looks good. My wife tells me this that evening, and I think well that's interesting for him to say, and we joke that he won't be there for long.

Several days ago we noticed that the outside unit, when it came on, was blowing out cold air instead of warm, so I went inside and the air coming out of the ducts felt cool. So, I went back outside and was doing some work nearby (the unit was still running) and then I heard the compressor kick on. I realized that what I'd been hearing was only the condenser fan. I walked over to the unit and sure enough it was blowing out warm air now. Went back inside and the air coming out of the ducts felt cool, perhaps cooler than before -- I really couldn't tell any difference. I took notice that this is now the way it's operating now: condenser fan comes on anywhere from 1 to 10 minutes before the compressor comes on.

We had the company come out to check it. Surprise, it's a new guy. The other one no longer works there. He says that the compressor is bad, and that it's not worth putting a new one in a 14 year old unit and that (surprise) we should buy a new unit. He says we can operate this one until it goes out, but that it's on its way, and pushes my wife pretty hard. She told him we'd get back to them.

I know next to nothing about HVAC, so I'm hoping that someone here can tell me where to go next. I read on the net (so you know it's true) that somewhere around a third of the time a diagnosis of a bad compressor is not correct. I'm figuring that at the very least I need another HVAC company to come out and give me a diagnosis. Any thoughts beyond that would be greatly appreciated.

[gt1953]

Get a second opinion from another company a large name company. Do not mention about the first company.
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[KTPhil]

It could be the compressor, but also might be one of several pressure/temperature sensors that are part of the safe operating logic. Finding the latter requires a little more sophistication on the part of the technician, so the lazy or ignorant (or dishonest) ones just say to scrap it.

[julrich366]

My outside unit is a 35 year old Luxaire. Earlier this summer, it started to do the same thing...eventually the compressor would not kick on at all (just the fan).
The compressor's capacitor (looks almost identical but larger than a Bosch ignition coil) had gone bad. $75 later (parts and labor) it is fixed and has worked great.
Yes, a 35 y.o. outside unit is not the most efficient/etc....but now at this point I just want to see how long it will go til the compressor actually dies!
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'74 Vert ..lot's to still do.

[joe56vw]

some of these HVAC techs that have come out of the schools in the last decade or so are some of the worst techs out there
most are just glorified parts changers who have about zero diagnostic ability and when they run into something they can't easily figure out they tell you that your unit is too old and need replacing

my brother has been a HVAC tech for about 20 years now and always tells me about the complete morons straight out of school his company keeps hiring to be on his crew
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[wuzmop]

My symptoms were way different, but I just went thru a fiasco with my AC this weekend that might give you things to check on your own. You can you tube how to check each component. The only one needing special tools is the capacitor. You need a multitester that will read fahrads for that. My problem and what path I took:

Everything came on but the fan, compressor buzzed. When I shut the thermostat off, the power in most of the house went off with it.

1) U fix it guy, who is very knowlegable, said it was a short in the fan. I replaced the fan. Not it.

2) Checked all the attic wiring, nothing evident.

3) Saw that the contactor was pushing it when it got power.

4) Tested voltage at the contactor, there should be 120 on each side. I was getting 120 on one 4 on the other. That lead me to a voltage problem, possibly a bad breaker.

5) Checked the power at the fuse box. Only 120 coming into the house, should be 2 phases of 120 each.

6) Called the city and told them that, they came out messed around in the alley and everything came back on.

I had a friend help me who is an electricians helper and knows how to safely work around 220, it can KILL you, but I would start by checking the voltage at the contactor when the compressor isn't working. It has to have 120 volts +/- 10% on both sides to turn on the compressor. Any less and it won't kick on.
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[Bobnotch]

[bigdog1962]

This isn't going to help much but....AC problem at my house, heat pump blowing hot air. First company, reputable - said I needed to replace the whole unit which is 11 years old for $5000 - no other option. Second company, reputable, took the word of the first company about the diagnosis over the phone and gave me a quote over the phone - similar quote - no thanks. Third person that someone suggested at my wife's job, $1500 or replace the unit. I kept asking my friends if they knew anyone and finally got a name of someone that works at a smaller business and he gave me a qoute for $1100 or replace the whole unit and he would do it on his own time.

In the mean time I had put three window units in the bedrooms upstairs as I have two units - one upstairs and one downstairs. Upstairs was out.

I decided to go w the $1100. I do know the risks associated with it but it just goes to show that their are varying degrees of competence/honesty/or whatever the case may be just as their is in every business.

I would get at least 4 quotes.

[Bugdog67]

Thanks for all the replies. Yes, it's a heat pump, no it's not in defrost. Getting another opinion today from a company that comes highly recommended.

[Mr. Unpopular]

So is the house actually warm inside? You never mentioned that it wasn't cooling the house.
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[Bugdog67]

[VWCOOL]

Thanks for sharing... if this wasn't so serious it'd be comedic..

Do you reckon the '67 had a bit to do with it?!

[Erik G]

sorry, if you would have said this

[Bugdog67]