Where is the internal air intake of Suburban furnace?

[Astroboy]

It's a heat-exchanger system, right?

My furnace is located under Kitchen couter/cabinet. There are 4 ducts (2 big ones and 2 small ones), and I think I know where each leads (2 big ones -> rear bedroom & mid-corridor, 2 small ones -> bathroom & floor by the entrance).

This furnace is supposed to recirculate and heat the interior air. I only see outputs but I don't see intake port(s). ????

Where is it, or are they?

[Fyrzowt]

Inside the cabinet I believe. You probably have a gap (about 3") at the bottom of your cabinet/floor to allow air to reach the intake which is not visible from outside the cabinet.
That is how mine seems to be. (2000 Safari)
Dave

[Astroboy]

That make sence. Thanks.

Without knowing it for sure, I was beginning to doubt and was about to think that the furnace was taking in fresh air from the outside...

Well, now I know not to block those gaps and the space around it.

Mmmm, I must figure out a new location for my new SurgeGuard...

Thank U!

[Aage]

I guess they changed with time; ours has two holes on the outside. One is hot air exhaust, the other is fresh air intake.

The furnace butts up almost directly to the two holes.

[Astroboy]

Originally Posted by Aage

I guess they changed with time; ours has two holes on the outside. One is hot air exhaust, the other is fresh air intake.

The furnace butts up almost directly to the two holes.

Just to clarify, we all have 2 holes on exterior: 1. fresh-air intake, 2. hot exhaust for combustion. And the furnace butts up directly the exterior holes.

The initial discussion was about the interior ports; the furnace taking-in "cold air" and producing "heated air".

Our furnace is "heat-exchanger system", which means "dirty hot air" from the combustion does not mix with interior air. The heat from the "dirty hot air" is simply transferred to the "cold interior air" through radiator and having the two ducted along side each other.

During this process "dirty hot air" loses some of its heat to "cold interior air" and then expelled via the exhaust port. "Cold interior air" gains some heat and become "warm interior air".

[Aage]

Ah, OK, yes: this does make sense.

Therefore, since there is no "cold air return" plenums anywhere in my trailer, I would tend to agree that it has an input somewhere on the cabinet of the furnace.

[overlander63]

Yes, the cold air return is on the bottom of the furnace, generally furthest from the exterior, under the access door.