What is this thing in the return plenum box?

That’s the reason for listed dampers.

I’ll get you the reference later Bob. I’m headed out this evening for a little R&R.

You have to be kidding Bob.

Is that the best technical answer you have?

For someone not familiar with basic Garage Wall Fire Safety requirements, Yes. :smiley:

Takes a big man for you to admit that .:stuck_out_tongue:

CA Code and Uniform Code

406.1.4 Separation. Separations shall comply with the following:

  1. Ducts in a private garage and ducts penetrating the walls or ceilings separating the dwelling unit from the garage shall be constructed of a minimum 0.019-inch (0.48 mm) sheet steel and shall have no openings into the garage.

716.5 Where required.
Fire dampers, smoke dampers, combination fire/smoke dampers and ceiling radiation dampers shall be provided at the locations prescribed in Sections 716.5.1 through 716.5.5 and Section 716.6. Where an assembly is required to have both fire dampers and smoke dampers, combination fire/smoke dampers or a fire damper and a smoke damper shall be required.

716.5.1 Fire walls.

Ducts and air transfer openings permitted in fire walls in accordance with Section 705.11 shall be protected with listed fire dampers installed in accordance with their listing.[size=2][FONT=Times New Roman][FONT=Times New Roman][size=2][/FONT][/size][/size][/FONT]

Works for me but do you have any idea what the difference is.I suppose it is on the net.

Smoke and fire dampers have sensors for smoke and fire. The dampers posted in this thread are controlled by thermostats.

:mrgreen: :mrgreen: :mrgreen: