HVAC gurus, your input please (1 Viewer)

[4mydogs]

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.

 

[KLF]

Ya, I would start with another opinion.

But there is some truth to the notion that a newer unit will pay for itself with the savings in energy costs. Not sure where the payoff point is though in your case. The same can be said for major appliances, things like dishwashers and washers. Even if they are working fine, if they are more than 10 years old, you're money ahead to replace it because the new ones are so much more energy efficient.

 

[Living in the Past]

I would first find out the cause of the delay in the compressor starting. Could be the compressor is getting old and hard to start or could be a bad run capacitor. Some use two and one could be bad. I know back to the seventies GE (who sold out to Trane) used small capacitor that was wired direct so when off it would run warm and keep the oil in the compressor warm. Not sure if that's still the case for using two capacitors. They also make a hard start setup to give it a extra boost at start up. Could also be a contactor binding up and points not making contact right away. There is also a chance it could be a solid state board issue. Just went thru that on my American Standard (Trane). In my case it was the indoor blower not running sometimes. Replaced the board and fixed the problem. I believe the issue is a cracked solder joint but since I leave town for a few days at a time the last thing I want to come home to a 100 degree house and then listen to my wife telling me I knew you should have just replaced that part.

Since the company sold years ago and it sounds like you don't get the same tech every time I would get a second option from another company. At the age of your unit it may well be worth changing but it would depend on knowing what is really wrong and what was your unit's SEER. Back in the eighties the SEER rating double in a very short time. My unit is about ten years old and has a rating of 15 SEER. I believe unless I want to pay big bucks for a upgrade I'm not going to do a whole lot better. If I was younger I would look into the mini split systems. These are becoming very popular around the world. They give you better room to room control because each room has a small evaporator/indoor unit mounted to wall instead of a vent. I think the unit mounted to the wall is why they are becoming more popular here. These can be setup for one unit to do multiple I would have at least two separate units. I live in the Phoenix area (116 yesterday) and having your A/C completely down is scary. The PO installed my current unit, I wish he would have installed two smaller units. I have what left of this summer and next summer before my wife and I summer at our other home. Wouldn't be cost effective to replace a 15 SEER unit for that short of time.

 

[4mydogs]

Found another company that comes highly recommended by a home builder. Coming to evaluate today, so fingers are crossed.

Thanks.

 

[4mydogs]

Update: All that was wrong was the start capacitor. Repairman said that he replaces a lot of them, especially in the heat of the summer. So . . .

Company A: You need a new system, which will coast anywhere from $8K up.

Company B: Diagnoses problem and replaces bad part in 30 minutes. Cost: $225.

Needless to say, Company B get my business from now on.

 

[JohnVee]

I just had the capacitor go out completely, and that was solved the Company B method the first time around. I think I'll stick with them. The owner's a MUDder, too. There are still some good people in the trades. Funny thing is that it went out on the coolest day we've had in weeks.

 

[ff347]

At the part time opportunity every Monday morning brings a flood of dead capacitors. I would suggest having a spare or two depending on the type of system you have. They are the cheapest and first thing you can check. 15 minutes and you are back in business. It sounds cliche but they do not last like they used to. Most are under 20 bucks.


Sent from my iPod touch using IH8MUD Forum

 

[Living in the Past]

At the part time opportunity every Monday morning brings a flood of dead capacitors. I would suggest having a spare or two depending on the type of system you have. They are the cheapest and first thing you can check. 15 minutes and you are back in business. It sounds cliche but they do not last like they used to. Most are under 20 bucks.


Sent from my iPod touch using IH8MUD Forum

I agree that it seems capacitors don't hold up like they use to. Don't work in the field anymore but know of two cases of compressor run capacitors failing this summer. Doubt it's from removing PCBs from the oil. That was done many years ago. I remember Carrier made a package heatpump model 50YQ. Here in the Phoenix area the units that the control panel faced west and got the afternoon sun the run capacitor would explode and catch the wiring on fire. I worked for a large contractor who was the first company installing these. First couple we replaced the whole unit and sent them back to the factory. Carrier came up with a kit to relocate the capacitor into the outdoor fan section. It also located terminals down instead of horizontal so the heat would raise away from the terminals.

I started to pick up spare parts for my American Standard (Trane) just to have on hand. Probably need to make sure I have some run Capacitors as well.

 

[RAYJON]

what you are seeing in the different A/C contractors is common lately, My best friend of 30+ years teaches A/C at the community college and he says its really bad. Most of the guys that come out arn't trained to diagnose a unit only replace it as the profit margin in new units is stupid. Repair work is not a money maker and our disposable society now thinks its normal to just replace stuff. Glad to see you were smart and not taken advantage of.

BTW if you learn a little the units arn't that expensive and installing them isn't rocket science. Depending on how much you run it, a split system replacing the condenser with a more efficient one may pay for its self in a couple of years.. if its a package unit (big box with heat and a/c that just has ducts attached) look at replacing it yourself as its easy and they are much more efficient than the older ones.. all that connects to them are the gas line, ducts, control wires and a 220v feed..you could even make a deal with contractor B to do it as sluff work when his guys are not busy at a lower labor rate..

good luck..

 

[ff347]

Most of the "common" problems are really kind of easy to repair yourself, depending on what part of your system is not working. The bonus is those parts are relatively cheap also. Capicators, relays, fan switches, even the motors for the condensor and the air handler can be done without to much hassle.

 

[Living in the Past]

Depending on how much you run it, a split system replacing the condenser with a more efficient one may pay for its self in a couple of years.

Changing the condensing is one thing. Changing a outdoor unit of a heatpump is something else. Besides matching tonnage match the charge as while. Less refrigerant is needed in the heating cycle and how each manufacturer handle that can differ. Back in the eighties a builder was switching manufacturer to cut costs. Went from Carrier to Comfortmaker. So people touring the models wouldn't see carrier outdoor units and then end up with a Comfortmaker they has us attempte to replace just the outdoor units. Just couldn't make them work in both heating and cooling. In the end we replaced the indoor units as well. Even the same manufacturer units might not work. Make sure the air handler is a listed unit to go with the unit your installing. Straight cool units can be made to work but if it's not listed to go with your air handler your will not sure what SEER you'll end up with.

 

[pandasfj]

50% of compressors that are replaced are usually due to bad start capacitors. Wear n tear from heat can take out the potential relay and in turn damage the start capacitor. Rule of thumb is to always replace both and with clean,tight wire connections at all terminals,its a good chance your compressor will last a lot longer...hth...gil

 

[snorky18]

^^ And if you want your compressor to last even longer, look into a hard-start kit, which I believe used to (may still?) be standard on some units.

 

[Trollhole]

I only put hard start capacitors on compressors I knew were at the end of their service. In my opinion they are just band aids to a bigger problem. Checking winding resistance and amp load of the compressor gives a good indication of health of the motor. Replacing a cap doesn't always fix the problem. May work for a while. At 14-15 years old it's time to already have a good nest egg for a new system. They don't last forever.

 

[fieldsken1]

I only put hard start capacitors on compressors I knew were at the end of their service. In my opinion they are just band aids to a bigger problem. Checking winding resistance and amp load of the compressor gives a good indication of health of the motor. Replacing a cap doesn't always fix the problem. May work for a while. At 14-15 years old it's time to already have a good nest egg for a new system. They don't last forever.