Why the vents under the fireplace on a 355TH?

[dhaile]

Hello all. I have a 355th. There are 4 vents under the fireplace and 2 under the stairs that lead to the lower enclosed attic. What is this purpose? We had a toilet leak (cracked ring) that was allowing water to drip into that area. The leak produced an odor which lead me to follow the smell. I guess is that those vents are for heating circulation but I really don't see what good they do? Any thoughts?

[scott42blue]

They supply input air for heating system and prevent all of your tanks from freezing.
Scott

[dhaile]

Hmm... If that's the case then why does it have a heater outlet inside the attic (comes out of the ducting)? I have double checked this, and that duct blows out hot air when the furnace is on. The vents I guess could help circulate the hot air?

[scott42blue]

Input not output.

[GDRV Service]

Hmm... If that's the case then why does it have a heater outlet inside the attic (comes out of the ducting)? I have double checked this, and that duct blows out hot air when the furnace is on. The vents I guess could help circulate the hot air?

Hi @dhaile,

These vents are the cold air return to supply the furnace. Without them the furnace would limit out.

Best regards,
~ Janice