Furnace and Air-con together

[Glenda Clark]

I've got a new question to ask our members.
I'm having to live in my trailer again for the winter
in eastern washington.
When I turn on the furnace for heat , both the furnace
And over head Air Con turn on.
Why ? Any suggestions ?

[jsmith948]

Make sure that the fan switch on your thermostat is set to "auto".

[Glenda Clark]

It worked , thank you , thankyou.
Thought I was going to freeze to death last night.

[bobbecky]

Even if the fan were running while the furnace is on, the compressor is not running, so the fan would just be circulating the air inside the trailer, not cooling it.

[JRTJH]

The "auxiliary fan function" was added several years ago by Dometic to supplement the furnace heating inadequacies. If you think about it, "heat rises" and there's no "true circulation from the top" in a heat only situation. The vents are on the floor and the return air is in a cupboard or a grate under the refrigerator. Then, there's the issue of "limited airflow" any distance from the furnace. So, when first starting to warm up a cold trailer, there's minimal airflow through the furnace system and it seems like a "forever with no heating improvement" situation...

In comes the air conditioner with its more powerful fan.... Turn the thermostat fan switch to LOW and the hot air at the top of the main cabin is collected by the air conditioner and pushed through the roof vents to the far ends of the trailer... Once the trailer is warmed up (10 or 15 minutes) turn the thermostat fan switch to AUTO and the A/C fan stops blowing air, allowing the furnace to then maintain the trailer temperature....

It's not a "full time system" but a way to augment the furnace to move a lot of air quickly when first warming up the trailer.....

Some like it, some: well not so much....

[LHaven]

For those of you with inCommand units, note that "auto" is the only way to turn the AC fan off. If you set the fan to "off," it runs on low. Really! Who designed that?

[Gegrad]

I don't love to run the overhead fan much; I personally feel like it cools the trailer off faster than it heats it.

[skipbizzle]

In addition to circulating the warm air would it have something to do with bringing in some fresh air to offset carbon monoxide?

[LHaven]

No it's just a circulating fan on the air conditioner.