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

Harman

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

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.