General Air Conditioning | Technical Service Procedure
KMTC Series — Indoor Fan Motor and Barrel Removal
Removal, replacement and reassembly procedure for KMTC wall-mounted indoor units
Qualified personnel only: This procedure is intended for trained air-conditioning service technicians. Isolate electrical power before removing covers, connectors, sensors, the electrical assembly, drain pan, fan motor or fan barrel.
Critical reassembly point: The fan barrel must be correctly positioned and centred before tightening the grub screw. Incorrect alignment may cause rubbing, vibration or operational noise.
1. Overview
This guide provides the removal and reinstallation sequence for the indoor fan motor and crossflow fan barrel fitted to Fujitsu General KMTC wall-mounted indoor units.
The procedure requires removal of the intake grille, filters, front panel, electrical assembly, sensors, drain pan, fan motor housing and fan barrel. Careful routing and reconnection of all wiring, sensors and earth conductors is essential during reassembly.
| Procedure applies to | Typical service activity |
|---|---|
| KMTC series wall-mounted indoor units | Fan motor replacement, fan barrel replacement, deep cleaning, obstruction removal or noise investigation |
2. Safety precautions
| Electrical isolation | Switch the system off and isolate power at the approved isolator before commencing work. Confirm the unit is de-energised. |
| Refrigerant piping | Do not apply excessive force to the evaporator coil or refrigerant pipework. Avoid kinking, flattening or stressing copper tubes and joints. |
| Electrical harnesses | Label or photograph connectors before disconnection. Do not pull on wires. Release plugs by the connector body. |
| Coil and fan components | Protect coil fins, fan blades, sensor holders, drain-pan clips and plastic tabs from damage. |
3. Removal procedure
Step 1 — Remove the intake grille
- Open the intake grille fully.
- Press the left and right grille mounting shafts outward.
- Gently pull the grille away from the indoor unit.
Step 2 — Remove the filters and front-panel screws
- Lift each air filter slightly.
- Release the lower hooks and pull the filters out.
- Remove the five screws securing the front panel and electrical cover.
Step 3 — Remove the front panel and control cover
- Open the lower screw covers.
- Remove the two lower front-panel screws.
- Pull the lower edge of the front panel forward to release the clips.
- Lift and remove the front panel without forcing the hooks.
- Remove the control cover to access the electrical assembly and connectors.
Step 4 — Release the evaporator and electrical assemblies
- Remove the two screws securing the left-hand side of the evaporator assembly to the base assembly.
- Remove the single screw securing the electrical assembly.
Step 5 — Remove sensors, earth and cable restraints
- Unclip the USB assembly from the main frame.
- Remove the room thermistor and thermistor cage from the coil.
- Remove the pipe sensor from its holder.
- Cut the cable tie securing the sensor cables.
- Disconnect the earthing cable.
Record routing: Photograph the sensor locations and cable path before removal to support correct reassembly.
Step 6 — Disconnect fan and stepper motors
- Unplug the fan motor connector from the main control PCB.
- Unplug the stepper motor connector or connectors from the main control PCB.
- Remove the electrical box from the base assembly.
Step 7 — Remove the drain pan
- Remove the screw securing the right-hand side of the drain pan.
- Unclip the cable guide to allow the right-hand side of the drain pan to release.
- Release the drain-pan clips on both sides.
- Pull the drain pan downward and remove it from the unit.
Step 8 — Release the fan motor assembly
Remove the three screws securing the fan motor assembly:
- Two screws at the bottom
- One screw at the top
Step 9 — Loosen the fan-barrel grub screw
- Locate the grub screw on the right-hand side of the fan barrel.
- Loosen the grub screw sufficiently to separate the fan barrel from the motor shaft.
Do not fully remove unless necessary: Retaining the grub screw in the fan hub reduces the risk of loss.
Step 10 — Remove the fan barrel
- Carefully lift the left-hand side of the evaporator coil only as much as required.
- Slide the fan barrel out from beneath the coil.
- Avoid contact with coil fins and refrigerant pipework.
Step 11 — Remove the fan motor from its housing
- Pull the fan motor and surrounding housing from the right-hand side of the indoor unit.
- Unclip the two housing tabs.
- Separate the housing sections.
- Remove the fan motor from the housing.
4. Reassembly
Reassemble the indoor unit by reversing the removal sequence. Complete the following checks during reassembly rather than waiting until all covers are installed.
| Checkpoint | Required confirmation |
|---|---|
| Motor housing | Both housing tabs are fully engaged and the assembly is correctly seated. |
| Fan barrel position | Fan barrel is centred with suitable clearance at both ends and does not contact the housing. |
| Grub screw | Grub screw is aligned with the motor-shaft flat and tightened securely. |
| Drain pan | Both clips, cable guide and retaining screw are secure. Drain hose and seals remain correctly positioned. |
| Sensors | Room thermistor, thermistor cage and pipe sensor are returned to their original locations. |
| Electrical connections | Fan motor, stepper motor, USB assembly and all other connectors are fully seated. |
| Earthing | Earth conductor is reconnected and secured. |
| Cable routing | Harnesses are retained clear of the fan barrel, drain pan, sharp edges and moving components. |
Manual rotation check: Before reconnecting power, rotate the fan barrel by hand through several full revolutions. It must turn freely without rubbing, clicking, binding or contacting wiring.
5. Final checks
| Check | Verification |
|---|---|
| ☐ | All screws, clips, covers, filters and the intake grille are securely fitted. |
| ☐ | Fan barrel rotates freely by hand. |
| ☐ | No wiring or sensor cable is within the rotating fan area. |
| ☐ | Run the unit in test operation and confirm stable airflow. |
| ☐ | Confirm there is no rubbing, vibration, clicking, squeaking or contact noise. |
| ☐ | Check louvre and stepper-motor operation. |
| ☐ | Confirm condensate drains correctly and there are no water leaks. |
Do not return the unit to service if the fan barrel contacts the housing, the motor wiring is unsecured, a sensor is not correctly installed, the drain pan is not fully clipped into place, or abnormal noise remains during test operation.