Ameri-Therm Vent Damper

[Andrew MacDonald]

Does anyone have information on Ameri-Therm vent dampers? I seem to remember that they were pulled form the market many years ago, but I can't seem to find a reference. I read a few posts about the design flaws but nothing that says they were pulled. Any help would be appreciated.

[Gary Reecher]

I would always recommend to home owners that they would be removed when I did preventative maintenance inspections. A few years back the Davenport TV stations did a show on how the local football coach had a hospital stay from CO due to one of these on his furnace and it did not thermally open.

[Brian A. MacNeish]

Originally Posted by Gary Reecher

I would always recommend to home owners that they would be removed when I did preventative maintenance inspections. A few years back the Davenport TV stations did a show on how the local football coach had a hospital stay from CO due to one of these on his furnace and it did not thermally open.

I remember that either of Home Energy or Energy Design Update magazines did an article on the flue vent dampers in the late 80's/early 90's. Recommended not using them!

[Morgan M. Audetat]

This is correct. They worked great when new, closing on shutdown and opening only when the boiler or water heater were fired. Sadly when they got old and tired they did not open fully and caused poor draft/combustion making CO as a result.

New vent dampers save fuel by closing off the flue when the appliance is not burning, but the new dampers are motor driven and wired in series with the gas valve and other safety devices of the boiler.

All Ameri-therm automatic vent dampers, still in the field, should be taken out, by a professional, before the equipment is put into service.