Heat pumps · Error codes · Trianco
P028Trianco
P028 on a Trianco heat pump: DHW Leaving Water Temp. Sensor Fault
Short answer
On a Trianco heat pump, P028 means: DHW Leaving Water Temp. Sensor Fault. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 2 sources
What it means
The manual says: DHW Leaving Water Temp. Sensor Fault.
Part involved: temperature sensor/thermistor.
Likely causes:
- The temp. sensor is broken or short circuit.
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
- Check or change the temp. sensor.
Who to ask for: heat pump controls / electrical.
Certification: Competent heat pump engineer; electrical competence for work inside the unit.
What you might notice
Sources
- Trianco Activair R290 High Temperature Indoor Air Source Heat Pump (3.2kW wall hung) - Installation Operation and Service Manual ↗ · 2026-08 · page 32 · Reviewed 23 September 2026
- Trianco Activair Pro Air Source Heat Pump (R290 6/12/17kW) - Installation Operation and Service Manual ↗ · 06/2026 · page 39 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026