check-canbus-cable-connection on an IVT Greenline HE: Communication with the controller has been interrupted. The controller executes a new start if the alarm is still active after two hours. If more than three new starts have been carried out within one hour, the alarm Too high boot count I/O board BAS x (category A), Æ Chapter 17.9.7
Short answer
On an IVT heat pump, check-canbus-cable-connection means: Communication with the controller has been interrupted. The controller executes a new start if the alarm is still active after two hours. If more than three new starts have been carried out within one hour, the alarm Too high boot count I/O board BAS x (category A), Æ Chapter 17.9.7. 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: Communication with the controller has been interrupted. The controller executes a new start if the alarm is still active after two hours. If more than three new starts have been carried out within one hour, the alarm Too high boot count I/O board BAS x (category A), Æ Chapter 17.9.7 .
When it shows: Communication with the controller has been interrupted. The controller executes a new start if the alarm is still active after two hours. If more than three new starts have been carried out within one hour, the alarm Too high boot count I/O board BAS x (category A), Æ Chapter 17.9.7 .
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Manual reset: Acknowledge on control panel.
What you can check
- Note the full alarm text including the component designation (e.g. E21.T6) - IVT asks for it when you contact the dealer. Contact the dealer if the warning recurs often. Acknowledge once on the control panel; if the alarm returns, contact the installer.
What the engineer will check
- Check CAN-bus cable and connections between boards/room sensor; check board power.
Who to ask for: heat pump engineer.
What you might notice
Sources
- Installer Guide Greenline HE C6-C11 E6-E11 1x230V (6 720 802 419 (2012/06) en) ↗ · 6 720 802 419 (2012/06) · page 6 720 802 419 p.70 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026