When your pellet stove stops pushing warm air into the room, the convection blower motor is often the culprit. The Harman 3-21-33647 is the direct OEM replacement motor that restores proper heat distribution across a wide range of Harman pellet stove models -- no fabrication, no adapters, no guesswork. It runs on 115V household current at a quiet 1500 RPM and includes automatic overload protection to guard against burnout from blocked airflow or abnormal thermal conditions.
The convection blower motor is responsible for circulating room air across the heat exchanger and out into your living space. Unlike the combustion (exhaust) blower that handles flue gases, the convection blower moves the heated air you actually feel. A failing motor -- one that runs slow, cycles off on thermal overload, or stops entirely -- will cause your stove to run hot internally while delivering little warmth to the room.
Part number 3-21-33647 is the Harman-specified replacement for this motor across nearly two decades of pellet stove production. It is also cross-referenced and sold under NBK Parts number 20146, making it easy to confirm you have the right component before ordering.
Engineered to Harman specifications. Replaces the factory convection motor in 19 confirmed Harman pellet stove models without modification.
Built-in thermal overload protector shuts the motor down before damage occurs if airflow is restricted or the stove runs unusually hot.
Class B rated motor windings handle continuous heat exposure up to 130 deg C (266 deg F) rise above ambient -- appropriate for pellet stove service conditions.
Covers the full Harman P-series lineup, the Accentra insert, the Allure 50, the Advance, the Invincible series, and several legacy models.
The convection blower pulls cool room air in through the lower grille, passes it over the firebox and heat exchanger, and discharges warm air out through the top or front vents. It runs independently from the combustion blower and is controlled by a separate speed circuit or thermostat logic in the stove's control board.
Common symptoms of a failing convection blower motor include:
Before replacing the motor, confirm the fan blade spins freely by hand with power off. If it is stiff or wobbles, the bearing has failed and a motor replacement is warranted. If it spins freely and the motor still does not run, test for 115V at the motor leads with a multimeter before assuming the motor is at fault -- a failed capacitor or control board may be the actual cause.
This motor is confirmed to fit the following Harman pellet stove models:
If your model is not listed, compare your existing motor's voltage, RPM, and frame dimensions to the specifications on this page before ordering. Harman has used this motor across a long production run, and some earlier or later variants may share the same spec.
Replacing the convection blower motor on most Harman stoves is a straightforward process accessible to any mechanically inclined stove owner. General steps include: