MODERN BURNER UNIT (MBU)
UNIT MAINTENANCE PROCEDURES
Replace Control Knob. To replace the control knob assembly (1), remove the cap (2), and loosen the
retainer nut (3) ONLY enough to release the knob from the Fuel Delivery Block (4). Do not disassemble
the knob components. Remove the control knob assembly (1) taking care not to drop the spring (5)
located behind the knob.
Loosen the retainer nut (3) on the new knob with a screwdriver until it is just held in place. Make sure that
the spring (5) is in place on the Feedback Potentiometer (6). Using a screwdriver placed in the slot of the
retainer nut to hold it steady, press new control knob assembly (1) onto the needle valve shaft (7) aligning
the pins (8) on the back of the Control Knob with the two slots (9) in the face of the Feedback
Potentiometer. Press the Control Knob until the collet (10) on the back of the Control Knob is firmly
engaged on the needle valve shaft (7).
Secure the control knob assembly (1) by tightening the retainer nut (3) with a screwdriver. Replace the
Replacement of Control Knob Assembly
8 (back of knob)