Heat pumps · Error codes · Atlantic
370-77Atlantic
370-77 on an Atlantic heat pump: Heat sink thermistor error (inverter / P.F.C.)
Short answer
On an Atlantic heat pump, 370-77 means: Heat sink thermistor error (inverter / P.F.C.). The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the Alféa Excellia A.I. / Excellia Duo A.I. (R410A split, 11-16)
The manual says: Heat sink thermistor error (inverter / P.F.C.).
Likely causes:
- Temperature sensor short-circuit, open circuit, unplugged or faulty.
On the Alféa Extensa A.I. / Extensa Duo A.I. R32 (split, 3-10)
The manual says: Heat sink thermistor error (P.F.C.) (model 10).
Likely causes:
- Temperature sensor short-circuit, open circuit, unplugged or faulty.
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.
What you can check
- Note the error number/LED pattern shown and give it to your installer.
What the engineer will check
- Check sensor wiring and connector.
- Measure sensor resistance; replace if faulty.
Who to ask for: heat pump / electrical.
What you might notice
Sources
- Alféa Excellia A.I. Installation manual (U0611757_1876_EN_14) ↗ · U0611757_1876_EN_14 · page 77 · Reviewed 23 September 2026
- Alfea Extensa A.I. R32 Installation manual (U0671217_2114_EN_11) ↗ · U0671217_2114_EN_11 · page 72 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026