This details the the communication checks for the R32 Units. This is not for R410a models. Be sure to verify what you have before testing.

Communication Errors – Key Checks (R32 Units)

If you encounter a communication error on an R32 unit, follow these key steps:

1. Verify Wired Wi-Fi Module & Condensate Pumps

• If a wired Wi-Fi module is installed but Wi-Fi is unavailable, it can trigger a communication fault.

• Check any condensate pumps wired into the system—ensure none have opened a communication lead.

2. Check 3-Pole Disconnects

• Ensure all connections are tight and free of corrosion.

• Test across the disconnect for voltage drop—there should be none.

• If needed, reset the disconnect before proceeding.

3. Inspect Wiring & Grounding

• No wire nuts should ever be used on communication lines.

• Confirm correct wiring practices and proper equipment grounding.

4. Test for Communication Signal (R32-Specific Method)

• Step 1: Remove wire #3 at the indoor unit terminal block.

• Step 2: Test from the empty #3 screw to the ground screw.

  • ✅ Expected Reading: A steady voltage above 100 VDC.
    (This confirms a good signal is coming from the outdoor unit.)

• Step 3: Test from the removed wire #3 to the ground screw.

  • ✅ Expected Reading: A fluctuating voltage of 60 VDC or greater.
    (This confirms communication signal activity returning from the indoor unit.)

🔄 Note: These readings are the opposite of what you’d expect on R410A systems.

• If expected voltages are not present, investigate:

  • Damaged or miswired cables

  • Failed control board(s)

  • Open or shorted components

5. Verify Power to Indoor & Outdoor Units

• Ensure 230V is present at both indoor and outdoor units.

• If power is missing at the indoor unit, check for:

  • Blown fuses

  • Faulty wiring

• Outdoor unit fuses often protect the indoor board, so check both ends.

6. Check for Faulty Control Board & Components

Before replacing any control board, always test:

• EEV(s)

• Compressor

• Fan Motor(s)

⚠️ If one of these is faulty, replacing the board alone won’t solve the issue—it will likely fail again.

7. Replace the Active Filter Module (ACTPM)

When replacing a control board, also replace the Active Filter Module. The ACTPM protects against voltage spikes and electrical noise.

🆕 Note: On R32 units, the Active Filter Module (ACTPM) is built into the main board.
You no longer need to test or replace this as a separate component.

7. Final System Testing

After confirming all components and wiring, proceed with normal system testing and commissioning.

Component Failure Errors – Best Practices

For any error codes related to component failure:

• Double-check all major components:

  • EEV

  • Fan Motor

  • Compressor

🔧 Proactive Maintenance Tip

Encourage techs to test these components during regular PM calls. Early detection reduces callbacks and prevents unnecessary board replacements.