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Heat pumps · Error codes · Samsung
E221Samsung

E221 on a Samsung heat pump: Outdoor Temperature Sensor Error (open/short)

Short answer

On a Samsung heat pump, E221 means: Outdoor Temperature Sensor Error (open/short). The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.

Reviewed 23 September 2026 · 4 sources

What it means

On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)

The manual says: Outdoor Temperature Sensor Error (open/short).

Part involved: Outdoor Temperature Sensor Error (open/short).

When it shows: Unit self-diagnosis: Outdoor Temperature Sensor Error (open/short).

Likely causes:

  • Refrigerant-side temperature sensor open/short circuit, detached or mis-located; connector or PCB fault.
  • Engineer checks per Samsung service manual: Check sensor connection status, sensor location and sensor resistance against the Samsung resistance table (103 or 204 type); replace sensor or PCB if required.

On the EHS Mono R32 (AE***RXYD*G)

The manual says: OUTDOOR UNIT temperature sensor error.

Part involved: OUTDOOR UNIT temperature sensor error.

When it shows: Unit self-diagnosis: OUTDOOR UNIT temperature sensor error.

Likely causes:

  • Refrigerant-side temperature sensor open/short circuit, detached or mis-located; connector or PCB fault.
  • Engineer checks per Samsung service manual: Check sensor connection status, sensor location and sensor resistance against the Samsung resistance table (103 or 204 type); replace sensor or PCB if required.

On the EHS Split Generation 4 (AEX/AEN, 2014)

The manual says: Outdoor temp sensor error (open/short).

Part involved: Outdoor temp sensor error (open/short).

When it shows: Unit self-diagnosis: Outdoor temp sensor error (open/short).

Likely causes:

  • Refrigerant-side temperature sensor open/short circuit, detached or mis-located; connector or PCB fault.
  • Engineer checks per Samsung service manual: Check sensor connection status, sensor location and sensor resistance against the Samsung resistance table (103 or 204 type); replace sensor or PCB if required.

On the EHS Split R32 (AE***RXED*G)

The manual says: Outdoor Unit air temperature sensor error.

Part involved: Outdoor Unit air temperature sensor error.

When it shows: Unit self-diagnosis: Outdoor Unit air temperature sensor error.

Likely causes:

  • Refrigerant-side temperature sensor open/short circuit, detached or mis-located; connector or PCB fault.
  • Engineer checks per Samsung service manual: Check sensor connection status, sensor location and sensor resistance against the Samsung resistance table (103 or 204 type); replace sensor or PCB if required.

Is it safe?

Does the heat pump stop?Yes
Engineer needed?Yes

The heat pump stops until the fault clears or is reset.

Resetting itself: unknown.

Manual reset: unknown.

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; then contact your installer or Samsung service; Samsung manuals do not describe a homeowner reset for this code.

What the engineer will check

  • Check sensor connection status, sensor location and sensor resistance against the Samsung resistance table (103 or 204 type); replace sensor or PCB if required. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.

Who to ask for: Heat pump engineer (Samsung-trained).

Certification: Competent electrical worker (BS 7671).

What you might notice

What owners and engineers report

8 owner and engineer reports mention this.

  • No heating on the EHS Mono R32 (AE***RXYD*G): 6 reports
  • Keeps stopping / cutting out on the EHS Mono R32 (AE***RXYD*G): 2 reports

Sources

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 23 September 2026