Dear GrouseFeathers:
I appreciate the kind words. I'll in return offer my experiences.
For years we had an air-to-air Trane heat pump of SEER~13. We successfully ran it on both a Lincoln 12-Kw welding genset and our prime power-rated (more in a moment) generator.
We upgraded to a geothermal Climate Master heat pump with indoor Trane air handler and a CM desuperheater to furnish domestic hot water. SEER ~30+. We have run this entire system off the same units noted above. All with no problems.
I checked and know for certain the power outputted by the Lincoln welder is stable and of good quality under load. The prime power unit is by definition although it gets checked occasionally too.
Without an oscilloscope the best I can offer is to check voltage output when the generator is under maximum load---everything 'on' and all your motors starting at once. Under the same conditions, use a moderately priced true RMS multimeter that will measure frequency. If your voltage and frequency are stable under maximum load, my GUESS is that your electronic heat pump(s) will work fine.
Start your generator, apply no loads, then bring one heat pump online and see what happens. Make it cycle repeatedly, run it for an hour, work it hard, and watch the voltage and frequency.
I realize a risk is involved, but I'd rather know now than later.
I would suggest calling the local TechRep at the distributor, not the local HVAC guy, but my results doing so have been odd. I've had two different TechReps from two different national companies tell me their particular HVAC systems (one heat pump, one conventional) simply would not work off a generator.
Phooey! Electricity is electricity, power is power, watts is watts. What's that, you say?
I finally figured out by looking over one guy's shoulder that the manufacturer has in its Tech Manual to always say 'no' to generators, primarily because somebody might try to miswire a $20,000 system to a Chinee piece of junk and then try to get warranty work.
We commonly advise our neighbors to run their systems on high-quality generators and have no known problems.
For those still tuned in, a plug here for direct-vent propane (or natgas) heaters as a backup. These totally enclosed heaters draw outside air in to combust and exhaust back outside through a pipe-within-a-pipe. No carbon monoxide inside.
Also mentioned is not having enough generator to pick up the electric heat. I assume we're talking here about supplemental strip resistance heaters built into the heat pump air handler.
If you have sufficient generator capacity to live like you wish and have a bit of spare, you can cripple a portion of the strip heaters and leave the others functional. If uncertain how to do this, track down your local HVAC guy and ask for help. My strip heaters on our first unit were installed in 5-Kw increments. I put supplemental switches on two of the relays and could select 20-, 15-, 10-Kw outputs.
Our primary prime power-rated genset is 45-Kw 4-pole 1,800-rpm driven by a 300-CI Ford 6-cyl stationary engine on propane that burns about 5-gallons per hour at full load. It's only been fully loaded on test when tied to a resistance loadbank. And an embarrassing amount of propane standing by, ready to go by unlocking a valve. Flip the transfer switch, push a button, and we're good to go.
I hope this helps further the conversation and look forward to continued interaction.
Please post back your continuing experiences so we may all learn.
