A2 on a Kensa heat pump: Ground return temperature T6 below the Heating Mode anti-freeze limit (right-hand compressor, twin units only)
Short answer
On a Kensa heat pump, A2 means: Ground return temperature T6 below the Heating Mode anti-freeze limit (right-hand compressor, twin units only). The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 2 sources
What it means
The manual says: Ground return temperature T6 below the Heating Mode anti-freeze limit (right-hand compressor, twin units only).
Part involved: T6 ground return sensor / ground circuit.
When it shows: Error level per manual: Fault or Warning.
Likely causes:
- Insufficient ground-side flow, ground pump failure, low antifreeze concentration, incorrect ground temperature settings.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: yes - clears when condition clears (per manual action text).
Manual reset: unknown.
What you can check
- Note the code shown on the controller/LED; check the heat pump isolator and consumer-unit breaker are on; check thermostat/timer settings.
What the engineer will check
- Follow Kensa fault table actions: Insufficient ground-side flow, ground pump failure, low antifreeze concentration, incorrect ground temperature settings. As A1 for compressor 2.
Who to ask for: GSHP / ground-loop installer.
Certification: MCS-certified GSHP installer recommended; Kensa-trained.
What you might notice
Sources
- Q80 Series Heat Pump Operational Manual ↗ · Version 2 · page 23 · Reviewed 23 September 2026
- Shoebox Heat Pump Operational Manual (User Manual) ↗ · Version 8 · page 26 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026