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elinux7a@yahoo.com

new member

0 post(s)
posted on 7/24/2007
Past few weeks, my A/C is not able to bring down the indoor temperature and has run all day especially during hot weather. The t-stat is set to 78 degrees but in the afternoon the temperature always rise to 82 degrees. The HVAC contractor checked the system and put in coolant which helped very little (no changes in indoor temperature). He found out that my evaporator coil is rated 3-ton while my condenser is rated 4-ton. He initially said that my cooling system may be bit undersized - he thought 4.5-ton is appropriate for my house (2369 sq ft excluding basement) with volume ceilings and many windows. He then said replacing 3-ton evaporator coil with 4-ton should solve the current issue. I don't want oversized A/C since it would cycle too often and it is not good in long run. I think 4-ton is probably right for my house besides .5 ton doesn't seem lot to me. The contractor gave me a bid the other day he will replace the uncased ADP 3-ton coil with cased Goodman 4-ton. My condenser is Goodman 4-ton (SEER 13). My furnace is Carrier (previous owner decided not to install A/C when the house was built and added A/C later - I suspect someone took advantage of the previous owner by installing mismatched evaporator coil). I'm not sure about installing cased Goodman evaporator coil on top of Carrier furnace - it may fit well but it would look mismatched. Should I have the contractor install cased Carrier evaporator coil? Or would Goodman coil work better with Goodman condenser?

Feedback will be greatly appreciated. Let me know if I should consider up-size my cooling system.

 
 
Replies [ post reply ]
cplangelo@yahoo.com

junior member

7 post(s)
replied on 7/26/2007

IN RESPONSE TO YOUR COOLING ISSUE, HAVING A 3 TON COIL WITH A 4 TON CONDENSOR IS A SERIOUS PROBLEM. THE OUTDOOR UNIT CANNOT BE LARGER THAN THE OUTDOOR UNIT. THIS CAUSES LIQUID FLOOD-BACK TO THE COMPRESSOR DUE TO INDOOR COIL MASS AND METERING DEVICE. WHEN DEALING WITH 13 SEER, YOU MUST MATCH INDOOR COIL WITH MANUFACTURER'S OUTDOOR UNIT. OLD SCHOOL USE TO PERMIT MIX MATCHING MANUFACTURER COILS AND CONDENSORS WHICH IS NOT RECOMMENED IN TODAYS STANDARDS. AS FAR AS YOUR GAS FURNACE, JUST ENSURE THAT IT WILL PRODUCE 450 CFM PER TON AND THAT YOUR DUCT SYSTEM IS PROPERLY DESIGNED FOR A 4 TON SYSTEM.




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