Can a PowerAir duct fan be used with a dimmer?

Discussion in 'HVAC Heating & Cooling' started by rtc35, Nov 9, 2013.

  1. rtc35

    rtc35 New Member

    Feb 25, 2013
    Nova Scotia
    I'm using a duct fan (Model # 1950103 found here - main WEB.pdf) for an unconventional use. The heart of my question is, can I connect it to a dimmer so I can control its speed. I don't know much about wiring and current. I have one friend who says no, a dimmer won't work and another that says it will.

    I'll explain what I'm doing if you're curious. I have a rocket heater in my basement (a super efficient home-made furnace that burns 80-90% less wood - see here if you want more details:, but unlike most rocket heaters, I use 5 inch vent pipes to exhaust out of my basement window. Don't worry, the vent piping is 40 feet long and radiates almost all the heat into my basement, so it's only vaguely warm as it goes out of a plywood hole I fashioned to fit the window. The temperature exiting the vent is only about 85F / 30C. In a typical build, you would use an 8 or 10 inch vent surrounded by cob (mud/sand/straw mix) that acts as heat storage. I prefer rapid heat radiation, so I don't use the cob. Because I use such narrow piping, I require the use of the fan - not normally needed in a more conventional configuration, which regulates its own air flow through expansion and contraction of gases. Unfortunately for my set up, the fan blows significantly faster than I want it to. I want to be able to control it fairly precisely. 99% of the time, I want to run it slowly, but in case the flames crawl up the feed tube too high, I might need to turn it up so smoke doesn't creep into the room.

    Can anybody advise me on this? Thanks.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Feb 6, 2011
    Information Technology
    NW Ontario, Canada
    A light dimmer most likely will not work. Some motors but not all can be controlled by a variable speed control specifically designed for motors. You would need to check with the manufacturer if there is a compatible speed control.

    I have an inline centrifugal duct blower on a speed controller. While it will slow down the motor it make it hum almost as loud as if it were running full speed.
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  4. DonL

    DonL Jack of all trades Master of one

    Mar 30, 2011
    Rocket Scientist
    Houston, TX
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