Climate Wizard CW3 / CW6S – FC13 Recorded Only When Turning Unit OFF at Thermostat

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Diagnostic Guide

Applies To

• Climate Wizard CW3
• Climate Wizard CW6S
• MagIQtouch controllers
• Fault Code FC13 – Exhaust (Top) Motor Error

Symptom Summary

A Fault Code FC13 occurs only after turning the unit OFF at the thermostat, while:

• The unit operates normally in COOL or VENT mode
• No faults occur during normal running
• In Service Operating Screen, the fans only run when both are turned on together, not individually

Understanding Expected Operation

Normal shutdown behaviour (CW3/CW6S)

When COOL mode is switched OFF at the thermostat:

1. Bottom (Supply) fan stops immediately
2. Top (Exhaust) fan continues to run for 20 minutes
   • This is the drying cycle, preventing moisture and protecting cooling cores.
3. After 20 minutes, the exhaust fan switches off automatically.

If the exhaust fan fails to run during this drying cycle, the PCBA detects no communication from the top motor and logs FC13 Exhaust Motor Error.

Motor/PCBA Wiring Summary

Each motor has two connections to the PCBA:

Later units include colour‑coding:

• Black connectors = Top Exhaust Motor
• White connectors = Bottom Supply Motor

Incorrect wiring causes the PCBA to receive motor signals on the wrong inputs.

Cause: Communication Cables Swapped Between Motors

This symptom set always indicates that the motor communication cables have been accidentally swapped on the PCBA.

Why this causes FC13 only during shutdown

During normal operation:

• Both motors run, so the PCBA receives 2 valid comms signals
• Even if swapped, the PCBA “sees” two active feedback signals, so no fault is triggered

During shutdown:

• The bottom fan stops, but
• The top exhaust fan must continue to run for 20 minutes

Because the comms cables are swapped:

• The PCBA expects top fan feedback on the top motor input, but receives nothing
• The PCBA logs FC13 Exhaust Motor Error

Why both motors only run together in Service Mode

In Service Mode:

• Running fans individually fails because each motor is getting the wrong comms signal
• Running fans together causes both motors to send feedback, allowing the PCBA to see activity on both inputs, so both run

This confirms swapped communication cables.

Diagnostic Procedure

Step 1: Enter Service Operating Screen

• Navigate to:
  Menu → Settings → Service Mode → Service Operating Screen

Step 2: Test motors individually

• Turn Supply (Bottom) Fan ON → likely will not run
• Turn Exhaust (Top) Fan ON → likely will not run

Step 3: Turn both fans ON together

• Both motors now run
• This behaviour confirms swapped communication connections

Corrective Action

1. Isolate power

• Turn OFF mains power at isolator
• Ensure safe access to the PCBA enclosure

2. Inspect motor communication cables

Check the PCBA motor signal inputs:

Correct colours where applicable:

• Black = Top
• White = Bottom

If these are reversed → swap them.

3. Swap the two communication cables (if incorrect)

• Disconnect and reconnect into correct PCBA inputs
• Ensure cables are seated firmly
• Confirm no damage to cable sheathing or connectors

4. Restore power and retest

1. Reconnect mains power
2. Enter Service Mode → Motor Test
3. Test each motor individually:
   • Each motor should now run independently
4. Exit Service Mode
5. Run unit normally for at least 10 minutes
6. Turn OFF at thermostat
7. Confirm:
   • Exhaust fan runs for 20 minutes
   • No FC13 occurs

Resolution

If communication cables were swapped:

• Motor test now works correctly
• Exhaust fan runs during drying cycle
• FC13 disappears and does not recur

If FC13 still occurs:

• Check for damaged comms cables
• Check motor power cables
• Check for loose connectors at motor end
• Replace motor if signal feedback cannot be restored

Notes for Technicians

• This fault is extremely common after motor replacement, PCBA replacement, or wiring loom handling
• CW3/CW6S motor connectors are physically similar, making misconnection possible
• Always verify correct comms cable routing before closing the service panel

Important Motor Identification

• Top Motor = Exhaust Motor (FC13)
• Bottom Motor = Supply Motor (FC7)
• Always follow the printed labels on the PCBA, not the physical connector orientation.
  (Motor power/comm cable locations shown in Control Module Wiring Diagram – PDF pges.16–18)