Rooftop AC and furnace together?

Just happened to be watching a DVD in our SS Agile yesterday. Van was not on shore power; inverter was turned on for 120VAC to power the DVD player & TV, solar panels on roof were doing their job, and batteries were handling the load just fine.

It got cool, so I activated the thermostat, set the Mode to HEAT, set temp at 72, and both the furnace AND the rooftop AC started up! I didn't hear the compressor on the AC turn on, but of course it was impossible to hear the movie because of the rooftop AC fan noise.

With the inverter off, of course, the propane furnace works just fine; we have used it that way in the past.

Guess I had never tried to run the heat while the inverter was turned on before, but has anyone else ever noticed this?

What year Agile? What brand/model AC/Heat pump??????

Before I answer...

It was brand-new a year ago last spring, a 2015 model. We took delivery 30 April, 2015. It has one of those swoopy Dometic rooftop ACs, but I haven't climbed up there and removed panels (which is apparently necessary?) to determine the model number. It's not a heat pump; for heat we have a propane furnace located under the passenger side rear side seat -- pretty much under the TV/DVD space.

Like I said, I think it was only the fan that came on, not the compressor, but not 100% sure. Don't remember ever trying to turn on the furnace before while the inverter was supplying 120VAC, but I should think that I'd have to set t-tstat to COOL to get the AC to turn on….

If I'm not mistaken, if the Fan is set to either Hi or Low, the AC fan will kick on anytime you activated the AC or furnace...set the Fan to automatic (AU) and see if that corrects your problem.

Ah-ha! That might be it, as I changed the fan setting from HI to LOW last summer to try to alleviate the noise. Realizing that I had done that, I tried putting the fan back to HI, but that made no difference. Not sure I ever saw an AUTO setting, but I'll look later today; thanks for the suggestion!

RTSS, exactly correct. Not sure why, but I had never noticed the third option on the t-stat, "Au"; I had only ever seen "Hi" and "Lo". After setting it to auto, was able to run furnace and inverter with no AC fan. Thanks! Simple problem cleared up; as usual, operator error!