Propane furnace needs clean power from generator

[BillP]

I have a propane furnace that needs clean power when running on a portable generator.
We recently replaced our old furnace with a very small propane unit that hangs on the wall. It's about the size of a computer and draws about as much power as a computer and monitor or a TV.

We have tried to run this furnace off a portable lawnmower-engine-style generator but the furnace just won't turn on. Evidently its processor and internal clock rely too much on clean 60 Hz power and this little generator, while providing more than enough power for the house, cannot keep the propane furnace running.

What kind of APCC power conditioner or UPS would run this unit? It's a furnace but it draws relatively small amount of current and could certainly be run off a UPS or small power conditioner.

I look forward to your APCC product suggestions. Thanks!

Kriston