Heat pumps · Error codes · Trianco
E034Trianco · Activair Pro (AI) R290 6/12/17kW
E034 on a Trianco Activair Pro R290 6/12/17kW: Water Pressure Sensor Fault (for IDU)
Short answer
On a Trianco heat pump, E034 means: Water Pressure Sensor Fault (for IDU). The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Water Pressure Sensor Fault (for IDU).
Part involved: refrigerant pressure sensor/transducer.
Likely causes:
- Short circuit or open circuit detected by the indoor unit water pressure sensor.
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).
What the engineer will check
- Inspect the integrity of the indoor unit water pressure sensor.
- Verify the voltage at the water pressure sensor port is within 0.5-4.5 V.
Who to ask for: refrigeration / controls.
Certification: F-gas certified engineer if the refrigerant circuit is opened.
What you might notice
Sources
- Trianco Activair Pro Air Source Heat Pump (R290 6/12/17kW) - Installation Operation and Service Manual ↗ · 06/2026 · page 41 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026