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Digitizing the old Enviro Dial-A-Fire Convection blower Dial Control. :-)

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Don2222, Jun 12, 2014.

  1. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,856
    Loc:
    Salem NH
    Hello

    Anyone try this with their Enviro EF-2, EF-3, Napoleon NPS40, Harman, or Travis Lopi or Avalon AGP pellet stove or older model stove with a knob control for their distribution blower?

    Alot can be said for these old dial controls. They are simple to fix, easy to use and last along time because they are not easily suseptable to power surges.

    However when using potentiometers in an older electronic component circuit instead of triacs, you do loose some peak voltage to the blower and there is a higher current draw due to the greater electrical resistance of the pot. This means more watts and more money in electricity.

    This explains why Triacs are used in newer control panels. They can be biased with low voltage and switch the high 120 vac with no losses.

    This voltage and current meter display shows proof of the above statements.
    Note: The non linearity of the voltages vs the knob setting. Typical with potentiometers. That is whay they had pots with what they called Audio Taper. LOL

    Pics below show convection blower voltages for different settings.
    Pic 1 - MAX room blower setting.
    Pic 2 - Guage shows 96 volts drawing 22.5 amps
    Pic 3 - MIN room blower setting
    Pic 4 - Guage shows 33 volts drawing 2.2 amps
    Pic 5 - 1/2 room blower setting
    Pic 6 - Guage shows 38 volts drawing 3.8 amps
    Pic 7 - 3/4 room blower setting
    Pic 8 - Guage shows 44 volts drawing 4.7 amps
    Pic 9 - The fire!

    Attached Files:

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  2. MountainSean

    MountainSean Credo Quia Absurdum

    Joined:
    Sep 29, 2011
    Messages:
    259
    Loc:
    NW Montana
    I'm not sure what to make of your readings but the first seems way off kilter to me. 22.5 amps at 96 volts is 2160 watts which is 4 times higher than the entire stove should be drawing at max settings. Most house circuits are also only 20 amps which is below what the gauge says you are drawing and should cause your breaker to trip unless you have a higher amp circuit in use here. Further, that motor is only rated for about 1.6 amps at 115v so 22.5 amps would have caused that motor to skip right past smoking and go straight to exploding.
  3. johneh

    johneh Burning Hunk

    Joined:
    Dec 19, 2009
    Messages:
    235
    Loc:
    Lanark Ontario Canada
    I came to the same conclusion after reading the post
    I have an fe3 on a 15 amp circuit and my stove does not draw anywhere near that amperage
    as hopefully the circuit breaker would blow if it did
  4. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,856
    Loc:
    Salem NH
    I a
    I agree, I will check the reluctor or maybe reposition it and take the readings again. I have the stove plugged into a 20 amp circuit in the shed. The room blower is the original blower and the control is also the original. Johneh, can you take these readings on your stove for comparison?

    The control for the stove is 18 years old, and the potentiometer seems a little flaky (Which can be highly resistive) at the high end and on the Max dial setting.
    The room blower may be that old also.

    So I changed the reluctor tonight to the other AC leg and got the following.
    92 VAC at 20.8 amps on the Max setting. See pics below:
    Being around 20 or 22 amps may not be enough to trip the 20 amp circuit breaker.

    It may be a sign the control and circuit is going bad. So if someone could take the same measurements on another EF-2 or EF-3 it would be very helpful here.

    Attached Files:

    Last edited: Jun 13, 2014

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