E02 on a Trianco heat pump: Low Pressure Protection
Short answer
On a Trianco heat pump, E02 means: Low Pressure Protection. 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 · 2 sources
What it means
On the Activair High Temperature R290 (5/9/15/22kW)
The manual says: Low Pressure Protection.
Part involved: pressure switch / compressor discharge-suction.
Likely causes:
- Fluorine (refrigerant) leakage in the system.
- False connection or damage of low-pressure switch.
- Poor defrosting.
- Fins dirty and blocked, poor ventilation.
- Abnormal throttling.
- System blocking.
On the Activair R410A indoor wall hung 3kW (S300)
The manual says: Low pressure protection (suction pressure is low, low pressure switch action).
Part involved: pressure switch / compressor discharge-suction.
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 outdoor unit is not blocked by debris/snow and has its required clearances.
What the engineer will check
On the Activair High Temperature R290 (5/9/15/22kW)
- Investigate low pressure switch, heat exchanger fins and refrigerant system per listed causes.
Who to ask for: refrigeration.
Certification: F-gas certified refrigeration engineer (REFCOM or equivalent).
On the Activair R410A indoor wall hung 3kW (S300)
- Check the low-pressure switch or check if the refrigerant system has leaks.
Who to ask for: refrigeration.
Certification: F-gas certified refrigeration engineer (REFCOM or equivalent).
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 34 · Reviewed 23 September 2026
- Trianco Activair Wall Hung Air Source Heat Pump S300 (R410A indoor) - Installation Operation and Service Manual ↗ · 2023-07 · page 32 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026