F11 on a Trianco heat pump: Communication Fault between DSP and Communication board
Short answer
On a Trianco heat pump, F11 means: Communication Fault between DSP and Communication board. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 3 sources
What it means
On the Activair High Temperature R290 (5/9/15/22kW)
The manual says: Communication Fault between DSP and Communication board.
Part involved: controller/PCB communication.
Likely causes:
- DSP communication fault.
On the Activair R290 Indoor (3.2kW wall hung / 5kW floor standing)
The manual says: DSP and Comp. Driver Communication Fault.
Part involved: controller/PCB communication.
Likely causes:
- DSP and Inverter board communication failure.
On the Activair Pro (AI) R290 6/12/17kW
The manual says: DSP and Compressor Driver Communication Fault.
Part involved: controller/PCB communication.
Likely causes:
- Communication failure between the DSP and inverter board.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
What you can check
- Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
- Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).
- Check the controller display is lit and showing the code.
What the engineer will check
On the Activair High Temperature R290 (5/9/15/22kW)
- Check the inverter board connection.
- If no problem, replace compressor driver board.
Who to ask for: heat pump controls / electrical.
Certification: Electrical competence (Part P / qualified electrician) for work inside control panels.
On the Activair R290 Indoor (3.2kW wall hung / 5kW floor standing)
- Check the communication connection.
Who to ask for: heat pump controls / electrical.
Certification: Electrical competence (Part P / qualified electrician) for work inside control panels.
On the Activair Pro (AI) R290 6/12/17kW
- Check communication wiring and connections.
Who to ask for: heat pump controls / electrical.
Certification: Electrical competence (Part P / qualified electrician) for work inside control panels.
What you might notice
Sources
- Trianco Activair High Temperature Air Source Heat Pump (R290 5/9/15/22kW) - Installation Operation and Service Manual ↗ · November 2024 (PDF regenerated 2026-08) · page 36 · Reviewed 23 September 2026
- Trianco Activair R290 High Temperature Indoor Air Source Heat Pump (3.2kW wall hung) - Installation Operation and Service Manual ↗ · 2026-08 · page 34 · Reviewed 23 September 2026
- Trianco Activair Pro Air Source Heat Pump (R290 6/12/17kW) - Installation Operation and Service Manual ↗ · 06/2026 · page 42 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026