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

Communication Errors – Key Checks

If you encounter a communication error, follow these steps:

1. Verify Wired Wi-Fi Module & Condensate Pumps:

   • If a wired Wi-Fi module is installed but no Wi-Fi is available, it may trigger this fault.
   • Ensure any connected condensate pumps haven’t opened one of your leads.

2. Check 3-Pole Disconnects:

   • Confirm connections are tight and that there is no voltage drop across the switch.
   • Disconnect and reset before proceeding.

3. Inspect Wiring & Grounding:

   • Absolutely NO wire nuts on communication cables.
   • Verify proper wiring and grounding.

4. Test for Communication Signal:

   • Step 1: Remove wire #3 at the indoor unit.
   • Step 2: Test from the empty #3 screw to the ground screw.
   • Expected Reading: Look for a fluctuating 70–100 VDC signal (This confirms a good signal leaving the outdoor unit).

    

   • Step 3: Now, test from wire #3 to the ground screw.
   • Expected Reading: Again, look for a fluctuating 70–100 VDC signal (This confirms a good signal leaving the indoor unit).

    

   • If no signal is present, trace the issue back to faulty wiring, a failed board, or another component failure.

5. Verify Power to Indoor & Outdoor Units:

   • If 230V is missing at the indoor unit, suspect bad fuses or faulty wiring.
   • The fuses on the outdoor board protect the indoor unit.

6. Check for Faulty Control Board & Components:

   • Before replacing a board, always test:
     • EEV(s)
     • Compressor
     • Fan Motor(s)
   • If any of these are faulty, replacing the board alone won’t fix the problem—it will fail again.

7. Replace the Active Filter Module (ACTPM):

   • If replacing a board, always replace the Active Filter Module, which absorbs electrical fluctuations and prevents future failures.

8. Final Testing: After verifying all components, proceed with standard system testing.

Component Failure Errors – Best Practices

• For any error codes related to component failure, recheck all major components (EEV, Fan Motor, Compressor).
• Proactive Maintenance Tip: Encourage contractors to test these components during preventive maintenance (PM) calls as well.