ALRM001 on a Trianco Activair Indoor R32 5/7kW: Temperature probe malfunction
Short answer
On a Trianco heat pump, ALRM001 means: Temperature probe malfunction. 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: Temperature probe malfunction.
Part involved: temperature sensor/thermistor.
Likely causes:
- Probe disconnected, faulty or abnormal value (PT1, PT4, PT5, PT6, MT1-6).
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: Generally automatic when the activation condition clears (conditions must persist e.g. 30 s).
Manual reset: If the alarm trips repeatedly (e.g. 3 times in 1 hour) it must be reset manually by the Technical Assistance Centre (press and hold the reset key until padlock and alarm symbol clear).
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 the probe (PT1, PT4, PT5, PT6, MT1-6) connection and value; replace if faulty.
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 Indoor Air Source Heat Pump 5 & 7kW - Control Panel Operation Manual ↗ · 2024-11 · page 41-42 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026