Harman 3-21-08639 Combustion Blower Exhaust Fan Motor. 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. 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. 5 double paddle blade impeller, part #. 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 #. Is used on the Accentra Insert & P35i. 5 Single-Paddle blade Accentra FS, Invincible T, PC45, PF100, Pellet Pro II you need part #. Harman uses a threaded mounting post to secure most of their combustion motors which can become stripped. Here are the nuts that thread on to the posts, Part #HDW600. Replacement For Part Number. 120V, 60Hz, 1.75A, 3000RMP, 5/16″ Shaft Diameter, 1 13/16″ Shaft Length, 3-Wire Pigtail 1/4 female spade terminals. Accentra Cast Free Standing. Furnace & Boiler Systems. Assembly Instructions for 3-21-08639. 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. Always disconnect the power to the stove before attempting any service. 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. 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. 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. 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. Listing and template services provided by inkFrog.