Thermally Actuated Vent Dampers

[dtontarski]

What is the recommendation on how to report on thermally actuated vent dampers? I observed these installed on the furnace and water heater vents in a 1984 built home yesterday.

I understand that these were installed in the 80's energy crunch as they are designed to save heat by preventing heat loss up the vent.

I've read that the thermally actuated ones are not as efficient or as safe as the electric versions which are wired into the gas valves and open and close in sync with the gas valve and burner ignition.

(As they are in sync they open and close faster and therefore save more heat, and they have the safety feature that if they fail (say due to power loss) they fail in the open position and don't interfere with safe venting.)

I have read that the thermally actuated ones could fail in the closed position.

On the basis of what I have read, it seems like I should call these out as a potential safety issue and recommend removal.

What are the opinions of this forum's experts? How are others reporting on these?

Thanks - and Happy Holidays To All!

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[kurt]

I tell folks to take them out. They fail.

[dtontarski]

Wow...that was fast.

Thanks Kurt!

[Terence McCann]

Originally posted by kurt

I tell folks to take them out. They fail.

Amen. They're junk. Ranks right up there with clothes dryer vent diverters.

[SWagar]

I had an electrically activated vent damper installed on a new boiler years a few years back. It failed in about two years. It failed in the closed position, which would not allow the furnace to operate. And just as luck would have it, the vent damper failed on a weekend while I was away. That made for one cold Sunday night of sleeping. The repair was taking the stupid thing out so I didn't have to deal with the next one failing.

[dneipp]

On your thermal vent damper, I would take it off unless it was a Heatnapper. The Heatnapper was wired in series with the thermostat so if it did fail, or if the stack became blocked, etc. it would shut off the thermostat to prevent carbon monixde problems. [^]