- Heat pumps
- Air-to-water heat pump
E911
Samsung E911 on an EHS heat pump: low water flow with the pump running
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On Samsung EHS units, E911 means the flow switch does not detect enough flow with the water pump running. Check the gauge pressure and whether underfloor heating valves are closed, and call the Samsung technician.
Safety first
Stop and check this first
- Samsung says not to attempt to repair, disassemble or modify the product yourself. The R290 Mono uses flammable refrigerant: Samsung requires service engineers not to use ignition sources and, for a leaking unit, no ignition source within 6 metres.
Safe checks you can perform
- Mode in which it appears
- Gauge pressure
- Real flow and flow switch
Leave these tasks to a qualified professional
- Do not attempt this professional task: Measure flow against Samsung's threshold
- Do not attempt this professional task: Valve settings on underfloor systems
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Measure flow against Samsung's threshold
What they doThe technician measures flow with the pump running and compares it with the threshold for your unit's capacity.
They must show youthe measured flow against 7 or 12 l/min for your model.
In writingthe cause found, valve, pressure, air or switch, and what was done.
Valve settings on underfloor systems
What they doIf the system has underfloor heating, the technician checks the 2-way valve settings and that fan coils secure the minimum flow.
They must show youthe settings checked and the flow in the mode that failed.
In writingthe setting applied and the test in that mode without E911.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Mode in which it appears
- Who:
- you.
- How:
- note whether E911 shows while heating, cooling or making hot water and whether you have underfloor only or underfloor with fan coils.
- Result that matters:
- Samsung links E911 to the floor valve closing in cooling below 16 °C outlet and to underfloor only systems.
- If it shows while cooling with underfloor and fan coils:
- the floor valve closing is suspect; fan coils must secure minimum flow.
- If it shows while heating:
- the valve does not explain it all; pressure, air or the switch remain.
- Evidence to keep:
- a note of mode, date and time.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Gauge pressure
- Who:
- you, only reading the gauge.
- How:
- read the water circuit pressure with the system at rest.
- Result that matters:
- Samsung says to charge above 1.0 bar and keep nominal pressure around 1.0 bar.
- If it is below 1.0 bar:
- water is missing and air can get in; ask the technician to refill and find the loss.
- If it is around 1.0 bar or slightly above:
- lack of water is ruled out; valves, air or the switch remain.
- Evidence to keep:
- a photo of the gauge.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Real flow and flow switch
- Who:
- the Samsung technician.
- How:
- with the pump running they measure circuit flow, check the 2-way valves and test the flow switch and its connection.
- Result that matters:
- flow against 7 l/min up to 9 kW or 12 l/min above 9 kW.
- If real flow is below:
- a hydraulic cause, valve, air or pump, is confirmed.
- If real flow is above and E911 persists:
- the flow switch or its wiring is the suspect.
- Evidence to keep:
- a job sheet with the measured flow and the unit capacity.
Requires opening the hydro unit with power off. Samsung technician only.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Heat pumps
- Brand
- Samsung
- Product type
- Air-to-water heat pump
Known code variants
- EHS 911
- Samsung EHS E911
- Samsung heat pump E911
What it means
Samsung defines E911 as a flow switch open error while the water pump is running. It is detected when flow is low for 30 seconds at pump start or 15 seconds with the pump already running. The threshold is under 7 l/min on units up to 9 kW and under 12 l/min above 9 kW. Samsung cites closing 2-way or underfloor valves as a cause. After six detections E913 appears and the unit does not resume. The code does not say whether the problem is real low flow or the switch.
Warnings and stop conditions
- Highsource verified
Samsung says not to attempt to repair, disassemble or modify the product yourself. The R290 Mono uses flammable refrigerant: Samsung requires service engineers not to use ignition sources and, for a leaking unit, no ignition source within 6 metres.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Symptoms and causes
Probable causes · in order
- 2-way or underfloor valve closedCommon
Samsung says that with underfloor only, or in cooling with underfloor and fan coils, the floor valve can close and cause E911. It fits if it shows in one mode.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
- Low pressure or air in the circuitPossible
Samsung asks to keep nominal pressure around 1.0 bar so air does not enter. With less pressure or with air, the pump cannot move the minimum flow.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
- Flow switch or its signalPossible
If real flow is correct, the switch or its wiring can read open. Only the technician separates it by measuring flow and signal.
Evidence: Samsung EHS air to water heat pump wired remote controller and control kit user manual DB68-08470A-18 · Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Virtual technician
Does E911 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 2
Samsung EHS Mono R290 outdoor unit AE***CXYD** installation manual DB68-12496A-03
Samsung · 2026 · manual
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