Home Improvement → Re: Evergreen AC blower motor retrofit

This does not matter if you don't have multistage and/or variable speed refrigerant compressor and heat source. If the rest of the system is not designed around a variable speed blower you will throw off the temperature rise and superheat and find tripped temperature and pressure limit switches.

What I was thinking was interfacing it with 4 temperature sensors: 1 each in the air stream before and after the evap. coil, one on the liquid line and one on the gas return line. You could run the fan as required to keep the superheat where it should be under a wider range of ambient conditions.

Interesting idea. I would move the before-coil sensor to the furnace air intake to work with heating and cooling.

Processors can lock up/fail. I would also want a switch to take the processor out of line if it fails, and maybe have a separate thermostat to force power to the blower if the ambient falls below 45F.

Obviously this would be something that most of the potential Evergreen motor users should not consider doing, but it is fun to think about. In theory it could be ideal, but in practice I think it would be very failure prone.

Speaking of failures, I suspect that the Evergreen ECM motors would be more failure-prone than the classic motors. I wonder what the failure rates are.

If I were to win the lotto one thing I'd do is a AB controllogix PLC controlled AC system.

Imagine temp sensors at all key locations
a frequency drive unit for every electric motor
additional duct fans in the air ducts as well as butterfly valves to increase or decrease or cut air to any vent you want.

then some panel view units to control it.
and a Scada system to access it remotely

then work out all the math and put it into the programing.

next add in a greenhouse for outside air exchange.

and dual ducts for an alt airflow to be able to give just recirc when a room doesn't want cooling (or doesn't want heating)

oh man whould that be sweet, all motors would be running at the optimal speed (and data could be collected so over time the programing might be further improved) and every room would be the temp you picked as well as have fresh air all the time

Sounds like a Mitsubishi City Multi system to me.

Just throw a Metasys at it. Of course the big problem with those is the proprietary software needed to make major changes to the system.