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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8327
Experience:  Furnace, A/C and heat pump specialist.
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I found out that my exterior AC/heat pump (Lenox) and the interior

Customer Question

I found out that my exterior AC/heat pump (Lenox) and the interior one (whatever it's called) do not match. The outdoor unit is newer. The AC technician said that the outdoor unit does not have a sheet telling him how much to charge it because the two units are not recommended to go together. What exactly does this mean? The interior unit looks used. The original installer won't provide me with the paperwork showing its serial number so it's not under warranty. I bought this house new and the appliances were supposed to be new. What do you recommend? Just leaving as is or ??? Thanks.
Submitted: 2 years ago.
Category: HVAC
Expert:  airheatman replied 2 years ago.
Hello. My name is ***** ***** I'll do my best to help. Let's get started and see what we can do.OK here is what is going on. Sounds like your indoor unit,being older is probably about a 10 SEER unit. The newer outdoor is most likely at least a 13 SEER unit.Federal law stopped production of anything less than 13 SEER a few years back. So when your outdoor needed to be replaced, there was not a perfect available.Indoor coil (or air handler)should have been changed at that time or an expansion valve metering device installed to regulate flow of refrigerant.
The higher efficient equipment requires more refrigerant.ON a straight cool unit, it is relative easy to balance charge since we only use the indoor coil as an evaporator in summer.But since a heat pump reverse and uses both indoor coil as an evaporator in summer and outdoor coil as evaporator in winter, you would constantly have to adjust charge every season.
At this point the best thing to do is replace indoor unit to match outdoor.
Expert:  airheatman replied 2 years ago.
If you can provide model and serial numbers off labels on indoor and outdoor unit, I can tell what you actually have and make a recommendation more accurately