Samsung heat pump error codes
17 codes that Samsung publishes for its heat pumps, each with what it means, the likely cause, what you can safely check and when to call an installer. Tap your code:
Heat pump: do only the checks the maker gives the owner for that code — read the water pressure on the controller, keep the outdoor unit clear of leaves and snow, switch the power off and on where the maker says to. Keep the casing on: refrigerant, wiring and the water circuit’s parts are not owner work. Anything else is for the heat-pump installer or the maker’s service engineer: in the UK and EU only an F-gas certified technician may open the refrigerant circuit. Codes that need one are marked Installer.
Read this first
Samsung EHS air-to-water heat pumps show a fault as a three-digit number — 911, 202, 554 — on the wired remote controller’s screen or on the outdoor unit’s main circuit board. The manual prints the number alone; if your controller shows a letter in front of it, look up the number. The codes here come from the installation manual of the EHS Mono R-32 outdoor unit (AE***RXYDEG / AE***RXYDGG), written for the installer, so it gives no owner checks: each entry says which part of the system reports the error. Models differ: your model’s manual is the authority.
911 Low water flow
- What it means
- The water flow was too low within 30 seconds of the pump starting, or for 15 seconds once running. Reported by the control kit.
- Likely cause
- Too little water moving through the heat pump; the manual names the flow only, not a cause.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer: the manual’s own maintenance list (water pressure, water filter) is for qualified personnel.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
912 Flow while the pump is off
- What it means
- Normal water flow was detected for 10 minutes while the pump signal was off. Reported by the control kit.
- Likely cause
- Water moving through the unit when it should not; the manual gives no cause.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
101 Wiring error between control kit and outdoor unit
- What it means
- A wire connection error between the control kit and the outdoor unit.
- Likely cause
- The connection wiring between the two.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
201 202 Control kit and outdoor unit not communicating
- What it means
- 201: a matching error between the control kit and the outdoor unit; 202: they have not communicated for 3 minutes.
- Likely cause
- Communication wiring, power to one of the units, or a board.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
554 Gas leak error
- What it means
- The outdoor unit has detected a refrigerant gas leak.
- Likely cause
- A leak in the refrigerant circuit.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer: only an F-gas certified technician may find the leak and recharge the refrigerant.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
407 Compressor stopped by high pressure
- What it means
- The compressor was shut down because of high pressure.
- Likely cause
- Too high a refrigerant pressure.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
416 Compressor discharge overheated
- What it means
- The compressor’s discharge is overheated.
- Likely cause
- Overheating in the refrigerant circuit.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
403 Compressor freezing detected (cooling)
- What it means
- The outdoor unit detected compressor freezing during cooling operation.
- Likely cause
- A refrigerant-side protection in cooling mode.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
458 475 Outdoor fan error
- What it means
- An outdoor unit fan error: 458 fan 1, 475 fan 2.
- Likely cause
- The fan motor, its wiring, or something stopping the fan.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
425 Power line missing (three-phase)
- What it means
- A power source line is missing — three-phase models only.
- Likely cause
- One phase of the supply is missing.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer or an electrician.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
601 Wired remote controller not communicating
- What it means
- A communication error between the control kit and the wired remote controller.
- Likely cause
- The remote controller’s cable or connection.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
901 902 Water temperature sensor error
- What it means
- The water inlet (901) or water outlet (902) temperature sensor at the plate heat exchanger is open- or short-circuited.
- Likely cause
- A failed sensor or its wiring.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
904 Hot water tank sensor error
- What it means
- The domestic hot-water tank temperature sensor has an error.
- Likely cause
- A failed sensor or its wiring.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
919 Disinfection temperature not reached
- What it means
- The hot-water disinfection run did not reach its set temperature, or did not hold it for the time required.
- Likely cause
- The tank could not be heated high enough or long enough during the disinfection run.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: Samsung, Samsung — Air to Water Heat Pump Installation manual, Mono Outdoor Unit AE***RXYDEG / AE***RXYDGG (DB68-08408A-07, 2024-01-10): Error codes Checked 2026-09-29.
A code that is not listed here
The Mono manual lists many more codes than these. For one not listed here, note the number and call your installer or Samsung’s heat-pump service. Samsung’s maintenance list — water pressure above 0.3 bar, the water filter, the pressure relief valve, the glycol — is for qualified personnel at least once a year.
We list only codes the source below states. If your code is not here, it may belong to a model the source does not cover: your model’s manual is the authority.
Related pages
Source
Every code on this page comes from this page, published by Samsung and read on the date shown. Meanings are written in our own words; nothing is taken from other makes, other models or third-party code sites.