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View Full Version : Can uReplace a 10 seer ac condenser w/a 13 seer w/o changing the inside 10 seer unit


veryhotinny
Aug 15, 2009, 12:55 PM
We have a 10 seer 2.5 ton heat pump outside condensing ac unit, that sprung a leak that cannot be repaired. We have had 5 repairmen come out and look. 3 of them say we have to replace the inside 10 seer 2.5 ton compressor and furnace as well. 1 of the 5 says we can just replace the outside unit with a 13 seer and he will put in an expansion valve on the inside unit and it will work. The other guy says he can replace the outside 10 seer condenser with a 13 seer and just needs to change some wires in the inside unit and put in a new thermometer. Who do we believe? Bottom line is our unit's are all 18 years old and we know we should replace them all but that just is not in the budget for at least 2 years. We have been suffering through a really hot summer and can't take it anymore.

We are leaning toward going with the guy who will replace the outside unit with a 13 seer and change the expansion valve. Hubby's friend says this will work for a 1 year or so but because they are mis matched we will end up having to replace them all in a year, he also says because we are mis matching them we will be voiding the warranty on the new condenser. Is this true? Another guy says we aren't mismatching them because both inside and outisde units are both 2.5 tons and that is all that matters.

Please Please help us to figure out this confusing issue!

jackhardy
Aug 15, 2009, 06:41 PM
YES... getting a 13 seer 2.5 ton is OK.. as long as it is a 2.5 ton

wmproop
Aug 15, 2009, 08:16 PM
No,, the indoor evaporater coil is supposed to match the 13 seer condenser unit
The 13 seer unit needs a larger 13 seer evaporator coil,, and yes most companies will not warranty the new outside unit if the indoor coil doesn`t match

T-Top
Aug 15, 2009, 09:48 PM
You can put a 12,13,or 15 seer heat pump with your old coil but the seer rating will not be what the outside system is rated at. Never install a condenser larger than the evaporator coil.

hvac1000
Aug 16, 2009, 06:38 AM
Penny wise BUT pound foolish!

dac122
Aug 16, 2009, 08:29 AM
You have two issues: performance and warranty. It is unlikely you will get the full 13 SEER if sticking with your current indoor coil. It will be > 10 and < 13. Are you okay with operating costs that won't reach the full 13 SEER numbers?

As for the warranty, get the proposed make and model number and contact the manufacturer to see what they say.

I think the labor, part cost and guess work in balancing your system would be better spent on a new indoor coil that will contain the TXV anyway. So I wouldn't go that way.

flattop43
Jun 11, 2012, 07:26 PM
It is best to stay with the same brand, however some brands are compatible. Thing to remember the dif between 10 and 13 seer is the size of the condenser coil and the fan and blade moving the air, if you have a 2.5 ton then replace it with a 2.5 ton, never go higher that the evaporator inside. As well as the blower is designed to move only so much air as well. Changing out the condenser only will last many years... as long as preventive maintenance is conducted. Filter changes so on...

blpreal
Jul 18, 2012, 08:26 AM
I have a carrier furnace that is probably 10-11 seers. It is 31 years old.

My heat pump is now an Amana which is 11 years old. It needs a compressor.

My question is: if I replace the compressor in the exterior pump; and the evaporator coils goes out in the interior furnace later, can I get evaporator coils to match the 10-11 seer heat/air exterior pump?

I need you help. Please e-mail [email protected]

hvac1000
Jul 18, 2012, 12:47 PM
New more efficient coils will work well with older equipment as long as the proper expansion valve is used. The big question is the room for the new coil. The new coils are much larger and can be a real pain to install on a old system. Best to replace the furnace and new indoor coil at the same time as a new outside unit.