E440 on a Samsung heat pump: Forbid Heat mode Operation when Outdoor Temperature is over 43 °C
Short answer
On a Samsung heat pump, E440 means: Forbid Heat mode Operation when Outdoor Temperature is over 43 °C. The heat pump keeps running with some functions stopped. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 3 sources
What it means
On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)
The manual says: Forbid Heat mode Operation when Outdoor Temperature is over 43 °C.
Part involved: Operating range control (outdoor temperature).
When it shows: Unit self-diagnosis: Forbid Heat mode Operation when Outdoor Temperature is over 43 °C.
Likely causes:
- Operation mode blocked because outdoor temperature is outside the permitted range for that mode; may also be a setting or outdoor sensor fault.
- Engineer checks per Samsung service manual: Check the operation setting state and outdoor temperature sensor.
On the EHS Mono R32 (AE***RXYD*G)
The manual says: Heating operation blocked (outdoor temperature over 35°C).
Part involved: Operating range control (outdoor temperature).
When it shows: Unit self-diagnosis: Heating operation blocked (outdoor temperature over 35°C).
Likely causes:
- Operation mode blocked because outdoor temperature is outside the permitted range for that mode; may also be a setting or outdoor sensor fault.
- Engineer checks per Samsung service manual: Check the operation setting state and outdoor temperature sensor.
On the EHS Split Generation 4 (AEX/AEN, 2014)
The manual says: Heating operation is not available since the outdoor air temperature is over 35°C.
Part involved: Operating range control (outdoor temperature).
When it shows: Unit self-diagnosis: Heating operation is not available since the outdoor air temperature is over 35°C.
Likely causes:
- Operation mode blocked because outdoor temperature is outside the permitted range for that mode; may also be a setting or outdoor sensor fault.
- Engineer checks per Samsung service manual: Check the operation setting state and outdoor temperature sensor.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Warning |
The heat pump keeps running with some functions stopped.
Resetting itself: yes - clears when conditions return within range.
Manual reset: not required.
What you can check
- Note the full error code shown on the controller; check the heat pump breaker/isolator in the consumer unit is ON; check thermostat/timer and controller operating-mode settings; note the outdoor temperature at the time; the code should clear when temperature returns within range.
What the engineer will check
- Check the operation setting state and outdoor temperature sensor. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.
Who to ask for: Heat pump engineer (only if persistent).
Certification: None specific.
What you might notice
What owners and engineers report
6 owner and engineer reports mention this.
- No heating on the EHS Mono R32 (AE***RXYD*G): 6 reports
Sources
- EHS R290 Mono Outdoor Unit Installation Manual AE***CXYD** (EU) DB68-12496A-03 ↗ · DB68-12496A-03 · page p.24 · Reviewed 23 September 2026
- EHS R-32 Mono Outdoor Unit Installation Manual (EU) DB68-08408A-07 ↗ · DB68-08408A-07 · page p.43 · Reviewed 23 September 2026
- Samsung Eco Heating System Service Manual - Outdoor Unit AEX060-160ED*HA / Hydro Unit AEN080/160YD*HA (file RC160MHXGA_SM_E_34513A(1)) ↗ · 34513A(1) · page ManualsLib viewer pp.52, 65 (printed pp.51, 64) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026