The Manufactured Housing Forums

First time owner here. I recently purchased a manufactured home approx. 26' x 64' with vaulted ceilings, no attic space. in the Calif. Sierra Foothills.
For the most part, I have figured out how everything works . . . . But, the one thing that has me puzzled is some sort of vent (i think) on the roof. There is no "grill / louver" on the inside, under this vent and the vent is powered with no switch. Sometimes I can hear it running, other times it does not. Most often I will heat it running very early in the morning.
Can someone tell me what this might be, the principal behind it's operation and what controls it?
Thanks for any help.

Don't make your roof ventilation broken. just carry some cement and wooden blocks and fix it where you want make ventilation.

Sounds like you may have the "Blend Air ll System". If you have a Coleman furnace pull off the face and look for a control box.
U tube has several videos on the system.
There should be a vented top on the stack.

I purchased a used Fleetwood model 4663E, 3 bedrooms, built in 1997. It has a manual "ventilation switch". (Not automatic) I was told to "turn it on occasionally. However, I am not there all the time.
What does this do / what is the purpose? How critical is it, and how often should it be turned on?
It seems like in cold weather, we are just sending out heated air to the outside.

The furnace has a sticker that indicates it is a Colman EVCON furnace. There is also a sticker Central Electric Furnaces for manufactured / modular housing, model # EB15B, Serial # 960257938. I don't see a connection to the ventilation switch. I see nothing that indicates a "blend air II system" or anything else.

When and how often should this switch be turned on?
Do I need to be concerned if the fan is not turned on often?
Is there an update that would make it automatic?
Recommendations / Suggestions?