E554 on a Samsung heat pump: GasLeak Error
Short answer
On a Samsung heat pump, E554 means: GasLeak Error. 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 · 2 sources
What it means
On the EHS Mono HT Quiet (AE***BXYD*G)
The manual says: GasLeak Error.
Part involved: Refrigerant circuit.
When it shows: Unit self-diagnosis: GasLeak Error.
Likely causes:
- Refrigerant leakage/shortage detected, or service valve closed, sensor fault or installation error.
- Engineer checks per Samsung service manual: Check refrigerant charge, indoor EVA sensor, that outdoor service valves are open, and that pipe/wiring installation is correct.
On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)
The manual says: Refrigerant leakage error (detection during system operation).
Part involved: Refrigerant circuit.
When it shows: Unit self-diagnosis: Refrigerant leakage error (detection during system operation).
Likely causes:
- Refrigerant leakage/shortage detected, or service valve closed, sensor fault or installation error.
- Engineer checks per Samsung service manual: Check refrigerant charge, indoor EVA sensor, that outdoor service valves are open, and that pipe/wiring installation is correct.
Is it safe?
Switch the heat pump off at its isolator and call an engineer.
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Safety lockout |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: unknown.
What you can check
On the EHS Mono HT Quiet (AE***BXYD*G)
- Note the full error code shown on the controller; check the heat pump breaker/isolator in the consumer unit is ON; leave the unit switched off at the isolator if advised; do not touch refrigerant pipework; then contact your installer or Samsung service; Samsung manuals do not describe a homeowner reset for this code.
On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)
- Note the full error code shown on the controller; check the heat pump breaker/isolator in the consumer unit is ON; switch off at the isolator and keep ignition sources away from the outdoor unit; do not touch refrigerant pipework; then contact your installer or Samsung service; Samsung manuals do not describe a homeowner reset for this code.
What the engineer will check
On the EHS Mono HT Quiet (AE***BXYD*G)
- Check refrigerant charge, indoor EVA sensor, that outdoor service valves are open, and that pipe/wiring installation is correct. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.
Who to ask for: F-gas certified refrigeration/heat pump engineer.
Certification: F-gas certification (UK F-gas Regulation; e.g. City & Guilds 2079 Cat I).
On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)
- Check refrigerant charge, indoor EVA sensor, that outdoor service valves are open, and that pipe/wiring installation is correct. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.
Who to ask for: F-gas certified refrigeration/heat pump engineer; R290 (A3 flammable refrigerant) competence.
Certification: F-gas certification (UK F-gas Regulation; e.g. City & Guilds 2079 Cat I); R290/flammable refrigerant handling training (e.g. hydrocarbon refrigerant course).
What you might notice
What owners and engineers report
2 owner and engineer reports mention this.
- No heating on the EHS Mono HT Quiet (AE***BXYD*G): 1 report
- Insufficient heating (house not warm enough) on the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K): 1 report
Sources
- Samsung EHS Service Manual - Eco Heating System Outdoor Unit / Tank Integrated Hydro Unit (Split, Mono, Mono HT) Code AC-00242E_2 (Jul 2022) ↗ · AC-00242E_2 (2022 edition) · page ManualsLib viewer pp.105-106 (printed pp.102-103) · Reviewed 23 September 2026
- EHS R290 Mono Outdoor Unit Installation Manual AE***CXYD** (EU) DB68-12496A-03 ↗ · DB68-12496A-03 · page p.24 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026