Heat pumps · Error codes · Atlantic
no-connectionAtlantic
no-connection on an Atlantic heat pump: No connection - failure to comply with room thermostat polarity
Short answer
On an Atlantic heat pump, no-connection means: No connection - failure to comply with room thermostat polarity. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 2 sources
What it means
The manual says: No connection - failure to comply with room thermostat polarity.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the error number/LED pattern shown and give it to your installer.
What the engineer will check
- Check room thermostat / sensor wiring polarity.
Sources
- alféa excellia duo Maintenance Document (U0546279_1738_EN_16) ↗ · U0546279_1738_EN_16 · page 68 · Reviewed 23 September 2026
- alféa extensa + Installation and operating manual (doc 1734-10, 1734-EN) ↗ · 1734-10 · page 74 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026