Replace coil or unit?

[Cyndil]

I have 2 Carrier units, a 3 ton upstairs model # 38BRCO36340 and a 3 1/2 ton downstairs. House was built in 2004 and we bought 1 1/2 years ago so do not know about routine maintance. I suspect there was none since the ac filters were beyond filthy when we purchased the house.

Last summer had to replace capacitors on both units. Now the upstairs unit coil has a large hole, which I have had confirmed by 2 companies. The coil is well over $0000 to replace which I consider a lot of money. Should I replace the entire unit since there will be no guarantee the condensor or something will not go out next week on this unit?

I am considering several options, just the coil (with the killer installation fee); a new "builder type" compressor and coil (keeping current heater); or getting a new higher seer unit complete with new heater like a Trane 16 or 20. I have been doing research all day long and I am very, very confused. I would truly appreciate some input on what I should do?

I do not want to waste all of that money on a coil if I have to replace something else next year. Also, my husband loves the Trane brand, so any input on that would be appreciated too.

We live in Houston, Texas btw so you know we need our ac units!!
Thanks for any help.

[BaldLoonie]

Guess that depends upon the budget. Put in a nice ADP (brand) coil with your 12 SEER A/C and you could have quite a bit of life left in the system. Replacing the outdoor unit too would bump you up to at max 14 SEER. If you wanted the utlimate SEER, then you would need to spend the big bucks for a all new with a high efficiency blower motor in the new furnace. Will it pay back in a reasonable time? Probably not what it saves over the 12 SEER will take a long time to give you a ROI. But it will be all new and you may be able to add something like dehumidify on demand which could increase comfort a bit.

[CallForHeat]

I'm from the old school, but I wouldn't think a brand new high efficiency unit would justify "paying for itself" at this time. If you are the type of person who would rather spend the extra money for peace of mind, then by all means do so. However, I would just replace the evaporator coil and be done with it. You have plenty, plenty of life left in your current system. Just like anything mechanical, the key is proper maintenance. Sign a service contract with a reputable company who will keep your system working properly for years to come. Ourdoor coils are MUCH less likely to incur leaks in comparison to indoor coils, so I wouldn't be too concerned with "your condenser having issues next week."

[Cyndil]

Guess that depends upon the budget. Put in a nice ADP (brand) coil with your 12 SEER A/C and you could have quite a bit of life left in the system. Replacing the outdoor unit too would bump you up to at max 14 SEER. If you wanted the utlimate SEER, then you would need to spend the big bucks for a all new with a high efficiency blower motor in the new furnace. Will it pay back in a reasonable time? Probably not what it saves over the 12 SEER will take a long time to give you a ROI. But it will be all new and you may be able to add something like dehumidify on demand which could increase comfort a bit.

My quote is for: 3 ton Standard box coil replacement ( Rheem / Goodman or equivalent)
Should I tell him I want him to use the ADP coil? Does the ADP coil come in different levels of durability/pricing or have you just had good results using the ADP brand?

[HVACTechNC]

Replace it with a coil that is matched with the condenser unit. A Rheem or Goodman coil is not a match with the Carrier condenser. A Goodman coil may come with a piston metering device when the Carrier condenser needs a TXV. Probably would work ok, but may lose efficiency.

I would not replace the system. Nobody can guarantee that a 7 year old system will not have additional service needs in the near future, but we will all agree that a 7 year old system should have 5-8 years of life left in it. A coil is a major repair, and hopefully, those dont come along that often. Odds are that other future service items would be much lower cost than that.

[BaldLoonie]

ADP is a coil maker, they make a rather generic coil that works with about anything. They are a good coil. They can be had with a piston that works on your existing R22. I'd bet that's what you have now. An expansion valve (TXV) is a better way of metering refrigerant and a R22 TXV can be put on an ADP coil. Rheem's coils only come with R410 TXVs and someone would have to unbraze the one that comes on the coil and replace it with a 22 TXV. I'm not sure I'd want a Goodman coil any more than another Carrier coil personally.

[Cyndil]

Thanks to you both for your help with this. I am now impressing my husband with my vast knowledge of HVAC lingo. I am throwing around things like, matching the condensor and coil so we do not lose efficiency and my favorite, the TXV.
Again, my sincere thanks.

[Cyndil]

Replace it with a coil that is matched with the condenser unit. A Rheem or Goodman coil is not a match with the Carrier condenser. A Goodman coil may come with a piston metering device when the Carrier condenser needs a TXV. Probably would work ok, but may lose efficiency.

I would not replace the system. Nobody can guarantee that a 7 year old system will not have additional service needs in the near future, but we will all agree that a 7 year old system should have 5-8 years of life left in it. A coil is a major repair, and hopefully, those dont come along that often. Odds are that other future service items would be much lower cost than that.

Do you like the ADP coil? Also, neither HVAC repairman I consulted had mentioned installing a Liquid Line Dryer. Is this something I should have installed when the new coil is installed?
My repairman said that the Rheem would match the Carrier. Should I call someone else? I had 2 people do service calls and I did not go with the first guy that came out because he said he would only use a Trane Coil.

[HVACTechNC]

ADP is a fine coil. My experience is that they are slightly less prone to leaking than some of the more well known brands. As for the Rheem coil, he may be right, as long as the metering device matches with the condensing unit specs then it will work ok.

Definately insist on a liquid line filter dryer being installed any time the refrigerant circuit is opened up to atmosphere. They are not expensive and can be installed in 10-15 minuites since the refrigerant will already be either recovered or trapped in the condenser.

Also, make sure the contractor trickles nitrogen through the line set as he brazes. Moisture in the atmospheric air causes oxidation inside the tubing which forms as non-condensables inside the tubing and can clog metering devices. Trickling nitrogen through the line set as they braze will prevent this oxidation.