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Heat pumps · Error codes · Samsung
E912Samsung

E912 on a Samsung heat pump: FLow Switch Close Error

Short answer

On a Samsung heat pump, E912 means: FLow Switch Close 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 · 5 sources

What it means

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

The manual says: FLow Switch Close Error.

Part involved: Water pump and flow sensor/switch.

When it shows: Unit self-diagnosis: FLow Switch Close Error.

Likely causes:

  • Water flow too low or flow sensor/switch signal inconsistent with pump state: low system pressure, air in system, blocked strainer/filter, closed valve, pump fault, flow switch/sensor or PCB fault, or an external pump creating flow.
  • Engineer checks per Samsung service manual: Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off.

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

The manual says: Normal flow rate error: in case of normal flow rate in 10min during water pump signal is OFF.

Part involved: Water pump and flow sensor/switch.

When it shows: Unit self-diagnosis: Normal flow rate error: in case of normal flow rate in 10min during water pump signal is OFF.

Likely causes:

  • Water flow too low or flow sensor/switch signal inconsistent with pump state: low system pressure, air in system, blocked strainer/filter, closed valve, pump fault, flow switch/sensor or PCB fault, or an external pump creating flow.
  • Engineer checks per Samsung service manual: Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off.

On the EHS Mono (R410A, AE***JXYD*H)

The manual says: Flow switch and water pump error (Water pump signal is OFF for 60sec during the F/S signal is ON).

Part involved: Water pump and flow sensor/switch.

When it shows: Unit self-diagnosis: Flow switch and water pump error (Water pump signal is OFF for 60sec during the F/S signal is ON).

Likely causes:

  • Water flow too low or flow sensor/switch signal inconsistent with pump state: low system pressure, air in system, blocked strainer/filter, closed valve, pump fault, flow switch/sensor or PCB fault, or an external pump creating flow.
  • Engineer checks per Samsung service manual: Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off.

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

The manual says: Water pump & flow switch ON: flow switch signal is on for 10 seconds while the water pump signal is off.

Part involved: Water pump and flow sensor/switch.

When it shows: Unit self-diagnosis: Water pump & flow switch ON: flow switch signal is on for 10 seconds while the water pump signal is off.

Likely causes:

  • Water flow too low or flow sensor/switch signal inconsistent with pump state: low system pressure, air in system, blocked strainer/filter, closed valve, pump fault, flow switch/sensor or PCB fault, or an external pump creating flow.
  • Engineer checks per Samsung service manual: Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off.

On the EHS TDM Plus (R410A)

The manual says: Flow switch and water pump error (F/S signal is ON for 10 min. during the Water pump signal is OFF).

Part involved: Water pump and flow sensor/switch.

When it shows: Unit self-diagnosis: Flow switch and water pump error (F/S signal is ON for 10 min. during the Water pump signal is OFF).

Likely causes:

  • Water flow too low or flow sensor/switch signal inconsistent with pump state: low system pressure, air in system, blocked strainer/filter, closed valve, pump fault, flow switch/sensor or PCB fault, or an external pump creating flow.
  • Engineer checks per Samsung service manual: Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off.

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; check the heating system pressure gauge reading (typically 1-2 bar when cold; do not top up unless you have been shown how); check the filling loop is closed; then contact your installer or Samsung service; Samsung manuals do not describe a homeowner reset for this code.

What the engineer will check

  • Check flow sensor/switch for short, PBA input, and whether an extra (external) pump is driving flow while the unit pump is off. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.

Who to ask for: Heat pump installer (wet system / hydraulics).

Certification: None specific (plumbing competence); competent electrical worker for pump/PCB electrical tests.

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