E177 on a Samsung heat pump: In hydro box, take place emergency signal Error
Short answer
On a Samsung heat pump, E177 means: In hydro box, take place emergency signal 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 · 3 sources
What it means
On the EHS Mono R290 (AE***CXYD*K and pump-integrated AE***CXYB*K)
The manual says: In hydro box, take place emergency signal Error.
Part involved: Hydro unit emergency stop input.
When it shows: Unit self-diagnosis: In hydro box, take place emergency signal Error.
Likely causes:
- Emergency stop signal generated by the hydro unit (external emergency/safety input).
- Engineer checks per Samsung service manual: Hydro unit has issued an emergency stop (external/emergency signal input); check the hydro unit and connected safety inputs.
On the EHS Split Generation 4 (AEX/AEN, 2014)
The manual says: Emergency stop: indoor unit (control kit) orders emergency stop.
Part involved: Hydro unit emergency stop input.
When it shows: Unit self-diagnosis: Emergency stop: indoor unit (control kit) orders emergency stop.
Likely causes:
- Emergency stop signal generated by the hydro unit (external emergency/safety input).
- Engineer checks per Samsung service manual: Hydro unit has issued an emergency stop (external/emergency signal input); check the hydro unit and connected safety inputs.
On the EHS TDM Plus (R410A)
The manual says: Emergency stop: indoor unit (Hydro Unit) orders emergency stop.
Part involved: Hydro unit emergency stop input.
When it shows: Unit self-diagnosis: Emergency stop: indoor unit (Hydro Unit) orders emergency stop.
Likely causes:
- Emergency stop signal generated by the hydro unit (external emergency/safety input).
- Engineer checks per Samsung service manual: Hydro unit has issued an emergency stop (external/emergency signal input); check the hydro unit and connected safety inputs.
Is it safe?
Switch the heat pump off at its isolator and call an engineer.
| 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
- Hydro unit has issued an emergency stop (external/emergency signal input); check the hydro unit and connected safety inputs. 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
Sources
- EHS R290 Mono Outdoor Unit Installation Manual AE***CXYD** (EU) DB68-12496A-03 ↗ · DB68-12496A-03 · page p.24 · 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 p.65 (printed p.64) · Reviewed 23 September 2026
- Samsung EHS TDM Plus Service Manual Code AC-07002A_0 (Feb 2017) ↗ · AC-07002A_0 · page p.89 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026