Harman Combustion Blower Exhaust Fan Motor, 3-21-08639-AMP

Save 25%
Original Price $119.99
Current Price $89.99

A $140.00 Savings vs the OEM

SKU 3-21-08639-SP4L
MPN 3-21-08639
In Stock
  • Aftermarket Part
  • Extremely Quiet
  • Fan blade impeller sold separately
  • Length 1 13⁄16" Diameter 5⁄16"
  • Wiring Connectors: 3-Wire Pig-tail with ¼" female spades
  • Volts 120 Amps 1.17
  • Cycles 60 Hz RMP 3000
  • Ships FREE with orders over $199
  • 30-Day Hassle Free Returns!
  • 90 Day Warranty Included
  • See Complete Description
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Frequently Bought Together


This exhaust blower motor is extremely durable and is used on most steel and cast iron Harman pellet stoves.  Some pellet stoves had an older version of this blower that looked much different. This motor design is updated as the replacement for all pellet-burning stoves. The blower motor comes with wire terminals and plugs directly into existing connections for all models.

Note: This blower motor DOES NOT come with an impeller. Harman uses 3 different sized impellers to fine-tune how much air is moved through the stove. It is advisable to purchase an impeller when replacing this blower as the old impeller from your existing blower may not come off the shaft (seized) or it may be damaged in the process of removing the blower.

    • 5" double paddle blade impeller, part # 3-20-502221 is used on the P38,43,61A, 68, PB105,PF100, XXV, 44 MAG, advance,Acc52i, DVC500, HF60
    • 4 3/4" Single paddle blade impeller, part # 3-21-00661 is used on the Accentra Insert & P35i
    • 5" Single-Paddle blade Accentra FS, Invincible T, PC45, PF100, Pellet Pro II you need part # 3-20-40985

    Harman uses a threaded mounting post to secure most of their combustion motors which can become stripped. They are sold individually and each motor uses three (3) Part # 1-00-53483208

    Here are the nuts that thread on to the posts, Part # HDW600

    Replacement For Part Numbers:
    • 3-21-08639
    • PP7613

    Click To See Compatible Models
    UPC: 652174686957

    Compatible Models


    • Optima PS1


    • Accentra 52i
    • Accentra Cast Free Standing
    • Accentra Insert
    • Advance
    • DVC 500
    • HF60
    • P35i
    • P35i-C
    • P38
    • P38+
    • P43
    • P43-C
    • P61
    • P61-C
    • P61A
    • P68
    • P68-C
    • PB105
    • PC45
    • PF100
    • PF120
    • XXV

    Technical Specs

    Volts 120
    Amps 1.17
    Cycles 60 Hz
    RPM 3000
    Shaft Diameter 5⁄16"
    Shaft Length 1 13⁄16"
    Wiring Connectors 3-Wire Pig-tail with ¼" female spades



    Assembly Instructions For Harman Combustion Blower Exhaust Fan Motor, 3-21-08639-AMP

    This combustion blower is used on all Harman pellet stoves so the specific instructions are going to vary by model, which are too many to explain in written detail, but here is a basic overview of what you will need to do:

    1. Always disconnect the power to the stove before attempting any service
    2. Except for the Invincible Series Inserts, Harman does not use a combustion blower housing for any of their pellet stoves. Instead, the motor is mounted either directly to the back of the stove, or they will have the motor mounted on a removable steel plate or hub or their own design. For motors mounted on the stove body, you will need to open the firebox, remove the combustion motor cover, remove the impeller from the motor shaft and then you can remove the motor from the back of the stove.
    3. In a perfect scenario, everything comes apart easily, however; the impeller can become seized on the motor shaft if it has never been removed, in which case the shaft of the motor must be cut. This will require a new impeller to be mounted on the new motor so you will want to have one of those on hand. See the description for this b lower to figure out which impeller you need, there are three (3) types to choose from, depending on your stove model. If you need to cut the shaft, a hand-held hacksaw blade is the best tool. It needs to be long and narrow because it need to fit between the motors cooling fan and the stove wall from behind the stove. You will also need to jam a screwdriver or something between the impeller and stove wall in the fire box to keep the shaft from spinning as you cut through the shaft. This same process may need to be done for stoves that use a removable hub but it will be easier because the whole assembly can be removed from the stove when cutting.
    4. All of these motors are secured to the stove using threaded studs which pass through the firebox or the hub and are wedged in place. If the stud is spinning when you are trying to remove the nut, the stud must also be cut in the same way as the shaft. This is not as common but it can happen. Links to these studs and replacement nuts are also in the description.
    5. Once everything is removed you will install your new studs is needed, install the motor to the stove or hub, install your existing or new impeller and then reconnect all of the wiring.


    Solving Combustion Blower Issues

    • If your stove is an insert and the venting was not cleaned properly while the stove was pulled out, there’s a good chance that ash fell down and is blocking the combustion blower from spinning.
    • If your stove has a combustion motor cover inside the stove, make sure it was put back and secure.
    • If your combustion blower is removable (Accentra Insert and XXV), make sure the blower is properly secured and tight-fitting. It is possible on these two stoves improperly install the blower.
    • If service was performed on the combustion blower itself, make sure the impeller blades aren’t rubbing against the cover or the cooling fan blades aren’t rubbing on their cover or a pellet isn’t obstructing the cooling fan from turning.
    • If wires were disconnected, make sure the combustion blower is plugged into the correct wires.
    • If the combustion blower is NOT turning and everything is wired correctly and nothing is obstructing it from turning… AND the Combustion Blower lights are illuminated on the control board, a new combustion blower will need to be installed.


    Unfortunately, sometimes products do not work like they are supposed to. We offer a 90 day warranty on manufacturer defects. Some manufacturers make this a very simple and easy process unfortunately others do not. Items must be used in accordance with the manufacturers guidelines to qualify for warranty replacement. Please be advised that warranty claims for these parts may take up to 4 weeks for processing, and customers must cover shipping.

    Shipping Info

    This Item Qualifies For Free Shipping With Orders Over $199!

    When Will My Order Ship

    All orders are typically processed within 24 hours of receiving payment and are shipped from us same day if placed before our shipping cutoff time (Monday - Friday: 1PM, Saturday: 10AM, Sunday: No Shipping), orders placed after our cutoff time are shipped the next morning.

    How Does Free Shipping Work?

    Most orders over $199 qualify for free shipping! Orders which ship for free are shipped with either USPS or UPS based on our discretion. If you are using a PO box, free shipping orders will always go USPS.

    Is Expedited Shipping Available?

    We offer both overnight and two day air shipping services for all orders placed within the Continental United States. For information on shipping cut-off times, go to our shipping page.

    Do You Ship To Canada?

    We ship to Canada! We estimate USPS to take 4-10 days once receiving your package from us. We do not offer expedited shipping of any kind to Canada. Please allow an extra 2-5 days for all shipments to Canada. Free shipping is not available to Canada.

    Do You Ship To Alaska Or Hawii?

    We ship to both Alaska and Hawaii! We do not offer next day or two day shipping to Alaska or Hawaii. Free shipping is not available to Alaska or Hawaii.

    Do You Ship Outside The US Or Canada?

    Unfortunately, at this time we do not offer international shipping other than to Canada.

    Shipping Time Estimations

    For information on shipping time estimations, see the Shipping Information & Transit Times on the shipping page.

    Read More About Our Shipping Information

    Customer Reviews

    Based on 51 reviews
    p68 parts

    Very fast shipping. Amazing company to deal with! A++++

    David S.
    Great Replacement / Cured vibration noise

    Awesome quality and quick delivery!
    This aftermarket version appeared to be identical to the OEM motor assy (including exact same cable assy length/connectors). Removing original motor was a challenge due to seized set screw; required some PB Blaster penetrating oil to remove set screw, but the Combustion Fan was also seized onto the motor shaft. I ultimately cut the old motor shaft (very quick sawzall cut) and was able to pull the Combustion Fan off (once I got it in a vice). I would highly suggest simply buying a replacement Combustion Fan to avoid the hassle of salvaging the original. Simply cut the original motor shaft and toss the motor and fan. Install was quick and simple.

    This cured the increasingly loud vibration/growling noise that I believe was attributed to the rubber isolation mounts on the OEM motor bracket. The mounts appeared to be dried/cracking and possibly overtightened from the factory, resulting in the brass mounts contacting the main back panel (amplifying the vibration/noise. Nice and quiet now!

    Michael S.

    Works great

    Michael W.
    Great Exhaust/Combustion Fan Replacement

    Perfect fit and works great!

    William W.

    Exactly what I ordered and fast delivery