Normal for rooftop to run continuously in furnace mode?

We have used the furnace a few times in cooler weather. Plan more significant use during our winter travels. The furnace vents near the floor produce a lot of heat when on. Perfect. But the rooftop/ceiling unit is also on and pushing air continuously whether or not the furnace is on. Is this normal?  Is there a way to change this so the roof unit circulates air only when the furnace is operating?

I have double / triple checked the control unit is in furnace mode not heat strip.

Rob

Check the fan mode.  Maybe you have it in something other than auto.  The rooftop unit should not operate just because the furnace is on.

Rob - we have the same issue. Prior to yesterday everything was operating normal both for the furnace and heat pump. We used the heat pump when on shore power and furnace when not. The only difference from your experience is that yesterday while driving we also had the furnace blower misteriously come on (the T-stat was set to off) and refused to shut off. It was not the normal fan speed nor sound, more of a pulsating sound. It finally just kept slowing and stopped on its own.
Now we have the same symptoms as you have, when set on furnace the AC unit fan also comes on and just blows air no heat or AC. I have tryed every setting on the T-stat, backwards and forward in every combination to no avail. I finally threw the AC breaker to kill the fan. Since both appliances are malfuntioning it would suggest that the T-stat Is the culprit. When we get home I plan to call PC for trouble shooting advise. For now it is wonderful and colorful in northern NH. - Dick

Might be useful for both of you to post the thermostat model for comparison.  I wonder if yours is different than my 2017 model?

The fan control must be set to "auto".

This is the kind of thermostat you both have. See this video https://www.youtube.com/watch?v=jbiUMa0cIJo&feature=youtu.be and see how it works. It must be set to auto.

My furnace fan came on for no reason and just pulsated off and on, it was raining, the calk around the square cover over the furnace was leaking. Water would complete the circuit and turn on the fan. I recaulked  and all is well. My air conditioning fan never came on.

   Lynn

Since the subject came up about furnaces.

When we bought our PC 11 years ago, our first cold night was at Brainard Lake in Colorado.  I turned on the furnace for the first time and it did not work.  I removed the outside furnace panel and found a switch, flipped it on and the furnace kicked-on.  I left the panel off for some minutes to make sure the system was all-good.  Standing outside, Irene starts screaming from inside that she is being asphyxiated.  I went inside the rig and sure enough, all the furnace fumes were inside the rig.

It didn't take long to figure out that the outside access panel is critical for isolating the fumes from the inside.  That tells me the gaskets on the furnace cover are extremely important to be in good condition.

Keep that one in-mind.