Heat pumps · Error codes · Trianco
Er05Trianco · Activair R32 (S700 / S1200 - FG 9007 / FG 9012)
Er05 on a Trianco Activair R32: High pressure protection
Short answer
On a Trianco heat pump, Er05 means: High pressure protection. 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: High pressure protection.
Part involved: pressure switch / compressor discharge-suction.
Likely causes:
- Inadequate flow rate.
- Uncompressed gas in refrigerant system.
- Overcharge with refrigerant.
- Water temperature setting too high.
- Outdoor fan ventilation is bad.
- Poor connection of pressure switch.
- Pressure switch failure.
- Main PCB damaged.
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
- Check pump and water control valve.
- Discharge and then re-charge the refrigerant.
- Discharge some refrigerant.
- Set lower water temp.
- Check fan ventilation.
- Reconnect the switch.
- Replace the pressure switch.
- Replace the PCB.
Who to ask for: refrigeration.
Certification: F-gas certified refrigeration engineer (REFCOM or equivalent).
What you might notice
Sources
- Trianco Activair Air Source Heat Pump S700, S1200 - Installation and Service Manual (R32, FG 9007 / FG 9012) ↗ · 2022-04 issue · page 11, 20 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026