Heat pumps · Error codes · Kensa
FGC1Kensa
FGC1 on a Kensa heat pump: Cooling-mode ground differential T5-T4 greater than set point
Short answer
On a Kensa heat pump, FGC1 means: Cooling-mode ground differential T5-T4 greater than set point. The heat pump keeps running.
Reviewed 23 September 2026 · 4 sources
What it means
The manual says: Cooling-mode ground differential T5-T4 greater than set point.
Part involved: Ground pump / ground flow.
When it shows: Error level per manual: Warning.
Likely causes:
- Low ground pump speed/flow, ground-side restriction, incorrect setting.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
The heat pump keeps running.
Resetting itself: n/a (warning).
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: Low ground pump speed/flow, ground-side restriction, incorrect setting.
Who to ask for: GSHP / ground-loop installer.
Certification: MCS-certified GSHP installer recommended; Kensa-trained.
What you might notice
Sources
- Kensa Evo Heat Pump Installation manual ↗ · V32 · page 51 · Reviewed 23 September 2026
- Q80 Series Heat Pump Operational Manual ↗ · Version 2 · page 24 · Reviewed 23 September 2026
- Shoebox Heat Pump Operational Manual (User Manual) ↗ · Version 8 · page 28 · Reviewed 23 September 2026
- Kensa Shoebox NX heat pump Installation manual ↗ · V12 · page 42 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026