Fuel Pump Coupling

Two-piece plug-in coupling connecting the fan motor shaft to the fuel pump. Transfers rotary drive between the two units.

Application

The coupling transfers rotary motion from the motor driving the fan directly to the fuel pump, allowing both components to be driven by a single motor. The flexible connection compensates for minor misalignment between the motor shaft and the pump shaft.

Symptoms – when to replace

• No fuel flow or uneven fuel delivery despite a sound fan motor and sound fuel pump.
• Audible knocking or rattling at the connection between the motor and the pump during burner operation.
• The coupling is visibly cracked, chipped, or excessively worn when disassembled.
• The fan motor runs correctly but the fuel pump doesn't turn at all – may indicate a completely failed coupling.

How to choose the right part

Selection is based on reference number 44085 – the same part fits the therm 715 and therm 1017, while the therm CA requires a different coupling (44.852 2), despite an identical function in the burner drive.

When replacing the coupling, also assess the condition of the fan motor and fuel pump at the mounting point – uneven coupling wear may indicate misalignment between these two components.