I had a bad leak in my AC coil ( Carrier CE3AXA042000ABAA 3.5 Ton) unit. I got several quotes to replace it and decided to go with a company that said that they with replace the coil with another Carrier coil that has a 10-year warranty for $1200. I was at work when they arrived and they had already removed the old coil and were hooking up the new coil. The new coil is a 4.0 Ton Comfortmaker model ( EHD2x48AA2 ) instead of a 3.5 Ton Carrier unit. The tech said that Comfortmaker and Carrier were made by the same company. I also asked him about the coil being a 4 Ton and not being matched with my Condenser being a ( York HACB042506A 3.5 Ton) unit, and he said that it was ok, and that was what they used to do to increase systems efficiency. Apparently the system also only has a 5-year warranty instead of a 10-year warranty. He had the Tech write on the ticket “10-year warranty for defects and 1-year labor warranty” and said that he would personally guarantee the additional 5 years. Am I being ripped off or not, and if so what should I do.

 

The tech is correct.
Having a coil of a smaller capacity than the outdoor unit is a NO GO, but the other way around does help improve the seer (efficiency).

 

The extra half ton coil size will be okay providing the refrigerant control metering device is matched to the condenser's capacity & not the evaporators larger capacity.

I would have advised you to install a Thermostatic Expansion Valve (TXV) metering device! TXV's adjust to the heatload that is put through the evaporator for optimal Superheat setpoint & efficient operation. TXV's also provide better protection against liquid refrigerant slugging of the compressor.

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- HVAC RETIRED