Central Air issues - should I consider replacing?
August 29, 2019 12:35 PM Subscribe
Our home A/C has been starting to give us issues this month (specifically a "Locked Rotor" error), and the tech thinks we might need to consider a replacement even though the system is only 9 years old and still under warranty. I've never dealt with HVAC replacements (expensive!) and have no clue what I'm doing. Best options?
We purchased our DC-area townhouse two years ago, rented it for two years prior to that. We've been going through the same large company for HVAC maintenance the prior owners used since the system was still under warranty. No issues dealing with company to date (mostly just used for biannual HVAC tune-ups, but also used the same company last year to replace our aging water heater).
HVAC info:
- Amana furnace and A/C, both installed in May 2010.
- A/C is a multistage, 3 Ton unit. I suspect the A/C is slightly oversized, online calculators say I probably need 2 - 2.5 Ton for our ~1800 sq ft townhouse but I know online calculators aren't the most accurate method of sizing.
- A/C is 19.0 SEER
- Standard forced-air gas furnace (so no heatpump).
- System uses a fancy 4-wire ComfortNet thermostat control/communication system. Thermostat is fairly complex (and pricey!) - can do advanced diagnostics, etc.
- 10-year warranty on both furnace and A/C, valid till May 2020.
- In four years of living here, only had one furnace issue - stuck solenoid, covered under warranty. Otherwise has been totally reliable.
A/C has also been 100% reliable until this month, when it stopped working and displayed an error message on the thermostat "04 LOCKED ROTOR". The company sent out a tech - he was convinced that it was due to a failing thermostat (I guess he thought it was seeing error codes not actually there??) and swapped it out for a new thermostat, fortunately for no charge since the system is under warranty. I think he also reset the outside part (condenser unit I think?) somehow. A/C comes back on and works great.
The next week we leave the country on vacation, and yesterday we finally come home to nonfunctional A/C, again. The brand-new thermostat displays the exact same error 04 LOCKED ROTOR. Another tech comes out. He doesn't touch the thermostat but does reset the condenser unit again (not sure it's a "reset" but something similar I think). A/C comes on again. He can't pinpoint a single point of failure, but he does suspect the condenser unit is dying and might need to be replaced.
We are fortunate to have more than enough money set aside to deal with it but we'd rather not waste large amounts of money if it's not needed. I am getting an estimate tomorrow to at least get a starting point, and plan to get more for such a pricey job, assuming I should replace it. I know I should do more homework on this but I just don't have the time or energy, and likely won't anytime soon. Admittedly if it was up to me I would just wait for it to die and salvage what I can from warranty (I can live without A/C, I've done it before) but Mrs. Photo Guy very quickly vetoed that idea.
So thoughts/suggestions? I'm no expert but this A/C is only 9 years old, seems rather early to deal with replacing it esp considering the very high cost of replacement. The company in question also offers a warranty buyout - no clue what that is or how that helps. Should we be looking at different manufacturers? The last tech called our A/C a "high-end model but crappy brand". Would we have to replace the furnace too? Is this a cheaper time of year to do it (end of summer season, less demand for A/C replacements?)
We purchased our DC-area townhouse two years ago, rented it for two years prior to that. We've been going through the same large company for HVAC maintenance the prior owners used since the system was still under warranty. No issues dealing with company to date (mostly just used for biannual HVAC tune-ups, but also used the same company last year to replace our aging water heater).
HVAC info:
- Amana furnace and A/C, both installed in May 2010.
- A/C is a multistage, 3 Ton unit. I suspect the A/C is slightly oversized, online calculators say I probably need 2 - 2.5 Ton for our ~1800 sq ft townhouse but I know online calculators aren't the most accurate method of sizing.
- A/C is 19.0 SEER
- Standard forced-air gas furnace (so no heatpump).
- System uses a fancy 4-wire ComfortNet thermostat control/communication system. Thermostat is fairly complex (and pricey!) - can do advanced diagnostics, etc.
- 10-year warranty on both furnace and A/C, valid till May 2020.
- In four years of living here, only had one furnace issue - stuck solenoid, covered under warranty. Otherwise has been totally reliable.
A/C has also been 100% reliable until this month, when it stopped working and displayed an error message on the thermostat "04 LOCKED ROTOR". The company sent out a tech - he was convinced that it was due to a failing thermostat (I guess he thought it was seeing error codes not actually there??) and swapped it out for a new thermostat, fortunately for no charge since the system is under warranty. I think he also reset the outside part (condenser unit I think?) somehow. A/C comes back on and works great.
The next week we leave the country on vacation, and yesterday we finally come home to nonfunctional A/C, again. The brand-new thermostat displays the exact same error 04 LOCKED ROTOR. Another tech comes out. He doesn't touch the thermostat but does reset the condenser unit again (not sure it's a "reset" but something similar I think). A/C comes on again. He can't pinpoint a single point of failure, but he does suspect the condenser unit is dying and might need to be replaced.
We are fortunate to have more than enough money set aside to deal with it but we'd rather not waste large amounts of money if it's not needed. I am getting an estimate tomorrow to at least get a starting point, and plan to get more for such a pricey job, assuming I should replace it. I know I should do more homework on this but I just don't have the time or energy, and likely won't anytime soon. Admittedly if it was up to me I would just wait for it to die and salvage what I can from warranty (I can live without A/C, I've done it before) but Mrs. Photo Guy very quickly vetoed that idea.
So thoughts/suggestions? I'm no expert but this A/C is only 9 years old, seems rather early to deal with replacing it esp considering the very high cost of replacement. The company in question also offers a warranty buyout - no clue what that is or how that helps. Should we be looking at different manufacturers? The last tech called our A/C a "high-end model but crappy brand". Would we have to replace the furnace too? Is this a cheaper time of year to do it (end of summer season, less demand for A/C replacements?)
I'm confused about the warranty. Is the problem that they'll come out and keep half-assedly fixing it but your spouse would prefer AC that works all the time and maybe warranty service is not going to cut it? Because otherwise my first approach would have nothing to do with my own money but just "Hey this is under warranty YOU fix it" and if they have to replace all the parts to do it, well I guess that's what happens.
posted by jessamyn at 12:41 PM on August 29, 2019 [3 favorites]
posted by jessamyn at 12:41 PM on August 29, 2019 [3 favorites]
Every HVAC company recommends replacement to see if you'll bite; they'd probably try it on the way out the door from initial installation if they think you're enough of a sucker. If the system is under warranty, call a manager (the techs' hands are tied on this, there's no point) and ask to have it explained like you're five how replacement on a nine-year-old system under warranty is something you're supposed to pay for.
Then see if you can get a couple opinions from other sources, if that doesn't look like it's working out in your favor. I'm pretty sure if the rotor can "lock", it can be replaced.
posted by Lyn Never at 1:07 PM on August 29, 2019 [6 favorites]
Then see if you can get a couple opinions from other sources, if that doesn't look like it's working out in your favor. I'm pretty sure if the rotor can "lock", it can be replaced.
posted by Lyn Never at 1:07 PM on August 29, 2019 [6 favorites]
AFAICT, "warranty buyout" means that, in the event that they cannot repair your current unit, they'll offer you current market value for it instead, which you could put towards a replacement.
Agreed with Lyn Never that if you've had multiple service calls for the same condenser-related issue on an appliance that is still under warranty the HVAC company should be replacing the condenser for no charge other than labour (if your warranty doesn't cover labour).
posted by tobascodagama at 1:14 PM on August 29, 2019
Agreed with Lyn Never that if you've had multiple service calls for the same condenser-related issue on an appliance that is still under warranty the HVAC company should be replacing the condenser for no charge other than labour (if your warranty doesn't cover labour).
posted by tobascodagama at 1:14 PM on August 29, 2019
I would not pay for replacement myself. If it needs to be replaced, the warranty should cover it. If it happens again I would push hard for them to replace it under the warranty, or else for them to send a tech that can diagnose the problem and fix it for real, not just wave their hands and say the brand is crappy and maybe you should buy a new one without actually doing anything helpful other than resetting it. If it is failing and it's broken down twice this month it will probably do so again before too long.
In the meantime if you want to get a quote from another contractor or two, it wouldn't hurt. They might give you some helpful info. But again, I wouldn't pay a third party to replace a unit that is still under warranty.
You might be right that the 3 ton unit is oversized. This would cause it to cycle on and off more frequently which could shorten the lifespan of the compressor; although a multistage unit would mitigate that somewhat. This would also result in moisture buildup in your house. Do you notice your house feeling cool but sort of damp and clammy in the summer, or do you get moisture problems like fogged up windows or condensation in weird spots or mold? Those would be warning signs of an oversized AC system.
posted by beandip at 1:16 PM on August 29, 2019 [2 favorites]
In the meantime if you want to get a quote from another contractor or two, it wouldn't hurt. They might give you some helpful info. But again, I wouldn't pay a third party to replace a unit that is still under warranty.
You might be right that the 3 ton unit is oversized. This would cause it to cycle on and off more frequently which could shorten the lifespan of the compressor; although a multistage unit would mitigate that somewhat. This would also result in moisture buildup in your house. Do you notice your house feeling cool but sort of damp and clammy in the summer, or do you get moisture problems like fogged up windows or condensation in weird spots or mold? Those would be warning signs of an oversized AC system.
posted by beandip at 1:16 PM on August 29, 2019 [2 favorites]
Best answer: Locked rotor means one of the motors (blower, condenser, maybe the outdoor condenser fan) is stuck and has been shut down to keep from overheating. If you’re lucky it’s a capacitor that needs to be replaced. If not then replace the motor and that should fix it. Replacing the condenser motor may require recharging the system, which complicates things.
At any rate I would assume the whole purpose of a warranty is to replace parts that are no longer functional during the warranty period. If this is untrue, I would proceed to use a different company to install a different brand HVAC unit.
posted by Huffy Puffy at 1:19 PM on August 29, 2019 [2 favorites]
At any rate I would assume the whole purpose of a warranty is to replace parts that are no longer functional during the warranty period. If this is untrue, I would proceed to use a different company to install a different brand HVAC unit.
posted by Huffy Puffy at 1:19 PM on August 29, 2019 [2 favorites]
Use the warranty. Go over the tech’s head and talk with a manager. Insist on a proper repair under warranty.
posted by Thorzdad at 1:27 PM on August 29, 2019
posted by Thorzdad at 1:27 PM on August 29, 2019
Response by poster: Regarding warranty, what I was told is that they cannot replace anything until it breaks, and it might/might not be traced down and fixed in the ~9 months left on the warranty. It also might be worth mentioning that the last service call was after hours - so the tech didn't get time to do in-depth troubleshooting before it was dark out. Maybe he meant they can use the "payout" of the warranty towards a new system?? Writing this I'm even more confused. Admittedly I was severely jetlagged last night and could not really follow what he was saying very well. I do plan to contact them tomorrow for clarification. Doubly frustrating as the warranty is through this company so I have to rely on them to fix this.
posted by photo guy at 1:55 PM on August 29, 2019
posted by photo guy at 1:55 PM on August 29, 2019
That explanation is horseshit. If they can’t figure out what’s wrong with your condenser in 9 months, they need re-examine their career choices. There are only so many rotors to lock in an ac system. What a joke.
posted by Admiral Haddock at 2:08 PM on August 29, 2019 [7 favorites]
posted by Admiral Haddock at 2:08 PM on August 29, 2019 [7 favorites]
I would call the supervisor, tell him that you having recurring problems and he needs to send a senior person to truly diagnose the problem. Sounds the people who came out so far and just going with the easy, generic guesses. Once they know what the problem is, they can quote you a price for fixing it as well as the value of buying out the warranty. Emphasize that the problem started when it started - this is not a new situation.
posted by metahawk at 2:08 PM on August 29, 2019 [1 favorite]
posted by metahawk at 2:08 PM on August 29, 2019 [1 favorite]
Best answer: If the AC company is a dealer or authorized service center for your brand of air conditioner, go over their head and call the manufacturer and explain your problem with them being unable to correctly diagnose and fix their unit.
If it's just the condensing unit that's failing you don't need to replace the whole system. While it would be best to replace the condenser with the same brand, that's not strictly necessary and a good AC tech and recommend a replacement. However, you can't go up or down on the capacity, a 3 ton condenser needs to be matched with a 3 ton evaporator. If you just replace the condenser it will have to be a 3 ton unit.
posted by Grumpy old geek at 3:11 PM on August 29, 2019 [2 favorites]
If it's just the condensing unit that's failing you don't need to replace the whole system. While it would be best to replace the condenser with the same brand, that's not strictly necessary and a good AC tech and recommend a replacement. However, you can't go up or down on the capacity, a 3 ton condenser needs to be matched with a 3 ton evaporator. If you just replace the condenser it will have to be a 3 ton unit.
posted by Grumpy old geek at 3:11 PM on August 29, 2019 [2 favorites]
Best answer: Capacitor on the fan motor, winding on the fan motor (in which case you replace the motor, these are pretty generic parts across the industry really), even a worn out contactor could just be sapping the voltage enough that the fan cant get the amps it needs to overcome the initial rotor magnet lock. If they send a smart tech, they can diagnose this exactly using their multimeter and then replace the affected part. This is the actual job, millions of folks know how to do this. I question their competence.
posted by some loser at 5:38 PM on August 29, 2019
posted by some loser at 5:38 PM on August 29, 2019
Condensing units really only have four parts: A compressor, a fan, a coil and some control circuity. From my chair this is likely a compressor. It's often cheaper to replace the whole unit rather than swapping out the compressor (there is a bunch of labour that needs to get done with a compressor replacement that is skipped with a complete unit replacement).
This really sounds like compressor to me. IME the fan motors on these units don't fail intermittently and they show obvious noise and/or vibration symptoms when they go bad.
Capacitors also don't fail intermittently though a run capacitor might cause the symptom if bad. This is a really easy check though so if the technicians are even half way competent they should have caught a bad cap.
Like some loser says this should be an easy diagnosis but the guys you dealt with so far might have only been parts changers running a script rather than technicians. Keep escalating the next time this happens. The "good" news is the fact the problem reoccurred within a couple days means the next failure will likely occur soon.
If you do replace don't worry about the evaporator manufacturer matching your condensing unit. An evaporator is just a fancy radiator; they aren't system specific. Also some evaporators are adjustable for tonnage by changing out an orifice so you might be able to change system size without changing the evaporator. But as you noted online calculators are nowhere near as accurate as an experienced installer on site.
All that said considering this is under warranty you shouldn't be paying for replacement but some warranties don't cover labour on condensing unit replacement - check the fine print.
posted by Mitheral at 10:51 PM on August 29, 2019
This really sounds like compressor to me. IME the fan motors on these units don't fail intermittently and they show obvious noise and/or vibration symptoms when they go bad.
Capacitors also don't fail intermittently though a run capacitor might cause the symptom if bad. This is a really easy check though so if the technicians are even half way competent they should have caught a bad cap.
Like some loser says this should be an easy diagnosis but the guys you dealt with so far might have only been parts changers running a script rather than technicians. Keep escalating the next time this happens. The "good" news is the fact the problem reoccurred within a couple days means the next failure will likely occur soon.
If you do replace don't worry about the evaporator manufacturer matching your condensing unit. An evaporator is just a fancy radiator; they aren't system specific. Also some evaporators are adjustable for tonnage by changing out an orifice so you might be able to change system size without changing the evaporator. But as you noted online calculators are nowhere near as accurate as an experienced installer on site.
All that said considering this is under warranty you shouldn't be paying for replacement but some warranties don't cover labour on condensing unit replacement - check the fine print.
posted by Mitheral at 10:51 PM on August 29, 2019
Response by poster: Thanks all. Got more info - the current warranty is parts AND labor, valid till June 2020. The company did do a quote for a replacement system, the "buyback" means they take $2000 off the cost of a new system since I still have a valid warranty. However even WITH that discount, I'm still looking at $6000 - $8000 for a full replacement (maybe marginally less if I replace the A/C only and leave the furnace in place). Yikes.
Think I'm just going to just let it run for the time being, and will keep calling for repairs so long as it's under warranty. Will push them harder to actually troubleshoot the next time it happens (and I'm sure it will).
posted by photo guy at 8:47 AM on August 30, 2019 [1 favorite]
Think I'm just going to just let it run for the time being, and will keep calling for repairs so long as it's under warranty. Will push them harder to actually troubleshoot the next time it happens (and I'm sure it will).
posted by photo guy at 8:47 AM on August 30, 2019 [1 favorite]
Response by poster: Last follow-up before I close out the question - the system failed again today, but I finally got a tech who could troubleshoot PROPERLY and explain exactly what's going wrong. Apparently the compressor is indeed dying (overheating plus making weird noises) but the system is NOT under warranty anymore since the prior homeowner (who actually bought the existing system) didn't properly transfer the warranty to us - I called the manufacturer myself and they confirmed this. So much for getting it fixed for free :(
Think we're going to just bite the bullet and replace it - the quotes for a new compressor are almost as much as a completely new system. The joys of owning a home!
posted by photo guy at 9:56 AM on September 16, 2019
Think we're going to just bite the bullet and replace it - the quotes for a new compressor are almost as much as a completely new system. The joys of owning a home!
posted by photo guy at 9:56 AM on September 16, 2019
This thread is closed to new comments.
posted by theora55 at 12:39 PM on August 29, 2019 [1 favorite]