Do I replace AC evaporative coil or get a new unit?

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Rob54keep
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Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Tue Oct 03, 2017 6:45 pm

My AC is 7 years old (live in Texas). The evaporative coil has a bad leak and does not hold refrig. and thus will not cool properly. The estimate to replace parts & labor is $3k. A new unit will probably costs $6-8k depending on the type unit. If the unit was 10 years or older I would automatically replace it all but at 7 years I'm thinking that this repair may be the best route. Compresssor etc. are aok. Comments/recommendation?

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Sandtrap
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Sandtrap » Tue Oct 03, 2017 6:52 pm

I'd have the coil replaced.

finite_difference
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Re: Do I replace AC evaporative coil or get a new unit?

Post by finite_difference » Tue Oct 03, 2017 6:56 pm

How long was the warranty on your AC?

How long is the warranty on a new coil?
The most precious gift we can offer anyone is our attention. - Thich Nhat Hanh

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lthenderson
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Re: Do I replace AC evaporative coil or get a new unit?

Post by lthenderson » Tue Oct 03, 2017 7:04 pm

I think your quote is on the very high side. I normally see them replaced for around $1500. I would shop around for another quote. Even if you can't get anything less, I would probably side with replacing it unless you've had other problems/complaints with the unit over the last seven years.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Tue Oct 03, 2017 7:30 pm

The warranty on the current unit has expired (bumper). The warranty on the new evap. coil is one year parts & labor and 5 years on parts (cost to replace the coil after one year would be about $1k). I replaced a capacitor last year (lifetime warranty on that), No other problems with the unit up to this point.

Also I may be moving within the next 2-5 years (wife may want to be closer to grand-baby)

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bottlecap
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Re: Do I replace AC evaporative coil or get a new unit?

Post by bottlecap » Tue Oct 03, 2017 7:50 pm

Then I'd definitely just replace the coil.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Tue Oct 03, 2017 8:03 pm

Thanks much for the good input. These decisions are never easy and sometimes it's like rolling the dice (or $$).

renue74
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Re: Do I replace AC evaporative coil or get a new unit?

Post by renue74 » Tue Oct 03, 2017 8:10 pm

I had an evaporator coil replaced on a crappy Goodman air handler about 5 years ago and it's still going strong.

Repair cost me $1000 and the part was under warranty. There was some minor welding that had to take place, but the project took the repair guy about 1/2 day to do and recharge the system.

strafe
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Re: Do I replace AC evaporative coil or get a new unit?

Post by strafe » Tue Oct 03, 2017 8:21 pm

What is a "unit?" I have no idea what you are asking. Do you have a packaged A/C (common in the south) or a split system? If the latter, are you talking about the furnace/air handler, condenser or both?

MadDwag
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Re: Do I replace AC evaporative coil or get a new unit?

Post by MadDwag » Tue Oct 03, 2017 8:30 pm

Agree with previous posters--just replace the coil. Quote sounds high, though.

Spirit Rider
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Spirit Rider » Tue Oct 03, 2017 8:34 pm

Is the current system R-22 or R-410a. This might factor into the decision.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Tue Oct 03, 2017 8:41 pm

Replacing the unit would include AC and furnace. It is a R-410a system. I'll check other reputable AC firms on their costs/warranty for the coil.

Lynn1987
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Lynn1987 » Tue Oct 03, 2017 8:58 pm

Just had the coil replaced in one of my units about a week ago. It was just under $1700, so I agree that $3k sounds high.

Spirit Rider
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Spirit Rider » Tue Oct 03, 2017 9:19 pm

There should be no reason to replace the furnace/air handler. The coil is an independent field replaceable unit. That is the likely reason your quote is unnecessarily high.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Tue Oct 03, 2017 9:29 pm

Great input for a non-mechanical / non-HVAC guy.

OldLearner
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Re: Do I replace AC evaporative coil or get a new unit?

Post by OldLearner » Tue Oct 03, 2017 10:03 pm

Rob54keep wrote:
Tue Oct 03, 2017 6:45 pm
My AC is 7 years old (live in Texas). The evaporative coil has a bad leak and does not hold refrig. and thus will not cool properly. The estimate to replace parts & labor is $3k. A new unit will probably costs $6-8k depending on the type unit. If the unit was 10 years or older I would automatically replace it all but at 7 years I'm thinking that this repair may be the best route. Compresssor etc. are aok. Comments/recommendation?
I'm going to disagree with the crowd on this one, but I've had awful luck with HVAC systems. If the price difference is only $3000 ($3000 for a coil vs $6000 for a whole new system), I'd spend the extra $3000 for a new system with a new warranty. It will be worth the extra money when you resell to say you have a whole new HVAC system (which is probably more efficient).

Also, if you're getting a $3000 price on a coil replacement, I have to question whether your HVAC guy wants the job.

NHRATA01
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Re: Do I replace AC evaporative coil or get a new unit?

Post by NHRATA01 » Wed Oct 04, 2017 1:12 pm

The fact that it's only 7 years old and 410a would make me lean towards replacing just the coil but getting a 2nd quote.

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Re: Do I replace AC evaporative coil or get a new unit?

Post by lazydavid » Wed Oct 04, 2017 1:21 pm

lthenderson wrote:
Tue Oct 03, 2017 7:04 pm
I think your quote is on the very high side. I normally see them replaced for around $1500. I would shop around for another quote. Even if you can't get anything less, I would probably side with replacing it unless you've had other problems/complaints with the unit over the last seven years.
^^this. Coils are not that expensive--$1500 sounds about right for a name-brand unit, plus a couple hundred bucks for installation. If you have a downdraft furnace where the coil is on the bottom--which necessitates removing the furnace to replace the coil--then labor might double the cost, so you'd probably be looking at around $2500-3000 installed. If it's an updraft or horizontally-mounted unit, the replacement labor should be relatively minimal and inexpensive.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Wed Oct 04, 2017 1:25 pm

Thanks for the input and price ranges. If you're not familiar with these systems (and I am not) it's very difficult to discern what is reasonable. There was also discussion how labor intensive it was to create a vacuum (or a clean line) in a closed system. How important is that in the installation process?

Spirit Rider
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Spirit Rider » Wed Oct 04, 2017 1:31 pm

NHRATA01 wrote:
Wed Oct 04, 2017 1:12 pm
The fact that it's only 7 years old and 410a would make me lean towards replacing just the coil but getting a 2nd quote.
I agree 100% with all three points.

boaski
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Re: Do I replace AC evaporative coil or get a new unit?

Post by boaski » Wed Oct 04, 2017 3:40 pm

It is very important to pull a vacuum but that is a standard procedure make sure they replace the filter dryer also but any good tech should know this but be careful alot of techs are on commission so I would at least get another quote.

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Fletch
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Fletch » Wed Oct 04, 2017 4:04 pm

Many (most?) new HVAC systems (furnace, AC, coil) come with 10 year warranty on parts and some manufacturers include 10 years on labor as well. Are you sure you are out of warranty?
“Meaningless! Meaningless!” says the Teacher. Whoever loves money never has enough; whoever loves wealth is never satisfied with their income. This too is meaningless.

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Rob54keep
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Re: Do I replace AC evaporative coil or get a new unit?

Post by Rob54keep » Wed Oct 04, 2017 5:26 pm

What a bummer. To get a 10 year warranty you MUST register the product within 60 days of installation. If you didn't, you have a 5 year warranty.

IowaFarmBoy
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Re: Do I replace AC evaporative coil or get a new unit?

Post by IowaFarmBoy » Wed Oct 04, 2017 7:42 pm

Our coil developed a leak after maybe ten years. Cost about $1000 to replace in a LCOL area. Ten years later it is going strong.

NHRATA01
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Re: Do I replace AC evaporative coil or get a new unit?

Post by NHRATA01 » Mon Oct 09, 2017 12:27 pm

Rob54keep wrote:
Wed Oct 04, 2017 1:25 pm
Thanks for the input and price ranges. If you're not familiar with these systems (and I am not) it's very difficult to discern what is reasonable. There was also discussion how labor intensive it was to create a vacuum (or a clean line) in a closed system. How important is that in the installation process?
It is definitely important to pull a vacuum, otherwise you have atmosphere and moisture (technically 14.7 psi of it) mixed in with the refrigerant.

Pulling a vacuum merely requires connecting an electric vacuum pump to one of the ports and letting it pump down. Ideally the tech should probably let it sit at vacuum for 30 minutes or so and watch for a pressure rise to make sure the new coil and connections aren't leaking. So it's not a labor intensive process.

As someone mentioned they probably should also replace the inline dryer since once exposed to atmosphere they'll get saturated with water. OTOH I've had an HVAC tech tell me a dryer really isn't that critical in HVAC, moreso in refrigeration. He installed one on my new unit this year, but we didn't find one on the old unit that we ripped out, go figure.

<--- Not an HVAC tech btw, although I am a MechE with some base knowledge in refrigeration.

riverguy
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Re: Do I replace AC evaporative coil or get a new unit?

Post by riverguy » Tue Oct 10, 2017 10:43 am

NHRATA01 wrote:
Mon Oct 09, 2017 12:27 pm
Rob54keep wrote:
Wed Oct 04, 2017 1:25 pm
Thanks for the input and price ranges. If you're not familiar with these systems (and I am not) it's very difficult to discern what is reasonable. There was also discussion how labor intensive it was to create a vacuum (or a clean line) in a closed system. How important is that in the installation process?
It is definitely important to pull a vacuum, otherwise you have atmosphere and moisture (technically 14.7 psi of it) mixed in with the refrigerant.

Pulling a vacuum merely requires connecting an electric vacuum pump to one of the ports and letting it pump down. Ideally the tech should probably let it sit at vacuum for 30 minutes or so and watch for a pressure rise to make sure the new coil and connections aren't leaking. So it's not a labor intensive process.

As someone mentioned they probably should also replace the inline dryer since once exposed to atmosphere they'll get saturated with water. OTOH I've had an HVAC tech tell me a dryer really isn't that critical in HVAC, moreso in refrigeration. He installed one on my new unit this year, but we didn't find one on the old unit that we ripped out, go figure.

<--- Not an HVAC tech btw, although I am a MechE with some base knowledge in refrigeration.
The proper way to do it is flow nitrogen through the system while brazing the new coil/components (replace drier) in place. Pressure test system with nitrogen. If that passes with no leaks, pull vacuum and recharge.

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Re: Do I replace AC evaporative coil or get a new unit?

Post by Spirit Rider » Tue Oct 10, 2017 3:41 pm

riverguy wrote:
Tue Oct 10, 2017 10:43 am
The proper way to do it is flow nitrogen through the system while brazing the new coil/components (replace drier) in place. Pressure test system with nitrogen. If that passes with no leaks, pull vacuum and recharge.
Correct, but do you know what low a percentage of HVAC techs/companies will do a nitrogen pressure test.

In a call to tech support on a new system a buddy DIY installed for his house (we did both of ours 20 year ago), the tech wouldn't answer any questions until he asked what steps he had used for installation. After being suitably impressed by the nitrogen pressure test. indicating that unlike many DIYers that he had 1/2 a clue. The tech mentioned that the stress test is something they try to instill in their dealers as a best practice, but very few do it.

In a thread on HVAC-Talk in the recent past there was a discussion of the value of nitrogen pressure testing (especially on R-410A). No more than 10% - 15% of techs replied that they did such tests. Many of them expressed that they wished they could, but their bosses would not let them take the time.

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