Friday, 15 July 2022

Use Heat Pump for Cooling Only. Bad idea?

SUMMARY: Due to new equipment availability, my HVAC contractor wants to install a heat pump for cooling only service. Is this a bad idea?

DETAILS: I live in northeast Texas in a 28 year old 2500 sq foot home. My the compressor on my original unit must have valve problems, as my suction pressure is high and discharge pressure is low, and can't keep up with 100 degree summer heat. I want to replace my system (120,000 BTU/hr natural gas furnace, 5 ton 10 SEER condenser) with a 16 SEER single speed A/C, an upflow 80% natural gas furnace, and add a 5" filter media cabinet. Furnace/coil is in a closet with 71 inch ceiling, so this height restriction somewhat limits what brand can be installed. (Trane/American Standard and Goodman/Amama fit. Carrier/Bryant are too tall for my closet ceiling.)

There is a shortage of 5 ton condensers, at least 16 SEER, in both single and two stage. Several companies are completely out and their distributors have no idea when more will be available. To help me out, a well-respected contractor that has been around for 50+ years has offered to install a 5 ton heat pump that will be working as cooling only. Bad idea??? AHRI efficiencies for this heat pump shows a lower SEER and EER than with the normal air conditioner condenser. (SEER drops from 16 to 15 and EER drops from 13 to 12.5.) I want the single speed system with an 80% efficient furnace to keep things simple and reliable using the KISS principle with less to go wrong

Is installing this heat pump to work in cooling mode only a mistake???

How should the contractor modify the heat pump? What is the proper way for the contracto to disabling the reversing valve? Is there more to do to make this set-up as reliable as possible? Defrost cycle? Is the defrost control board going to be a likely reliability problem?

Wiring from thermostat? With an AC condenser, only need Y and C wires. What about the O and B heat pump wires in this case?

All the added complexity is making me nervous. Will another HVAC tech be able to know what is going on with this set-up when they come to service or repair the unit?

Thanks,


source https://hvac-talk.com/vbb/threads/2240779-Use-Heat-Pump-for-Cooling-Only-Bad-idea?goto=newpost

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