I.003 on a Glow-worm GeniaAir: The maintenance time has been reached
Short answer
On a Glow-worm heat pump, I.003 means: The maintenance time has been reached. The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: The maintenance time has been reached.
Part involved: The maintenance time has been reached.
Likely causes:
- Maintenance interval elapsed.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: clears when condition resolved / engineer resets.
Manual reset: engineer resets (Installer level > Reset > Reset maintenance message).
What you can check
- Arrange the annual service with your installer.
What the engineer will check
- Carry out maintenance work; reset the service interval.
Who to ask for: Vaillant-trained heat pump installer/engineer (MCS-certified installer).
Certification: MCS installer certification; Vaillant product training recommended.
Sources
- GeniaAir Appliance Interface installation and maintenance instructions ↗ · 8000043014_01 · page HPIM 7 8000043014_01 p.29 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026