Suncourt ZoneMaster 8-Inch Normally Open Motorized Damper — Power Close/Spring Open 24V Vent Damper, Transformer Included (ZO208)

Work great, cheap price and made in the USA

Works as described. Includes a plug-in power supply but not the wires to connect the damper to the supply.The device is NOT UL or ETL listed (only the power supply is).When open the device consumes no power. When closed I measured a power consumption between 7.9W and 8.4W (8.1W average).

The media could not be loaded. This really works. Mine is in the attic, and I can't hear it at all from the 2nd floor bedroom just below it. The design uses a motor (not a solenoid) and has "lost motion" so the motor runs a few seconds before the driver bar actually engages the baffle. See the video for timing. You must leave power applied as long as you want it in the powered state... a spring drives it back to the starting position when you remove power.The motor gets very warm to the touch, but not dangerously hot. I measured the power draw and temperature but that was long before I wrote this review... maybe 10 W and 105 deg F? I'll update this review if I climb back up there and retest.I recommend using a power switch or plug with a built-in timer so you don't accidentally leave it in the actuated position all day and make your bedroom so hot the wife notices. Oh, and make sure you use plenty of foil hvac tape to avoid air leaks.Note: this design is either all-on or all-off... the design isn't amenable to driving the motor to a different position each time based on temperature measurements in the room.

Works just as expected with the foam gasket around edge of the valve virtually eliminates leakage

I haven't installed these yet and therefore haven't used them but I did wire them up and test them. After some needed modifications right out of the box I think they should work fine.I bought three of these 8" normally open. On all three of them, when the damper was fully closed the damper did not seal with the foam seal properly. There was anywhere from 1/4" to almost 1/2" gap between the foam seal and damper. I was concerned with a gap, there would be a whistling sound due to the air flowing through the gap when the HVAC was on and the damper closed. I ended up pulling off the foam seal, applying some rubber cement and moving the seal into a better position that created a proper seal between the closed damper and the foam material. Now there is no gap. It wasn't much work to do it and I think it'll hold but no product should need modifications right out of the box to work properly.

Direct replacement works good

24 volt transformer was missing with order. Also insulation strip was in wrong position so air was able to be supplied to room. Had to purchase transformer and new piece of insulation to get unit working properly.