NIBE heat pump error codes
13 codes that NIBE 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
NIBE heat pumps and indoor modules with the display NIBE calls the “Emmy display” show an alarm as a number with a short text. NIBE’s Alarm List for those products (version 1747-1, updated 2017-11-23) mentions the VVM 320 and VVM 500 indoor modules, the F750 exhaust-air heat pump and the F2030 and F2040 outdoor units by name, and gives each number its cause and what the heat pump does about it, such as “compressor blocked” or “automatic reset”. It is written for installers. For owners, NIBE’s VVM S320 manual says an alarm turns the status lamp steady red and that selecting “Reset alarm” is in many cases enough: a white lamp afterwards means the alarm is remedied, a red lamp or an alarm that returns means the cause is still there. Models differ: NIBE’s newer S-series controls show the alarm in words with a suggested action, and their alarm numbers were not checked against this list, so your model’s manual is the authority.
1 Sensor fault BT1 (outdoor sensor)
- What it means
- The outdoor temperature sensor, BT1, is not connected or is defective. The heat pump sets its calculated flow temperature to the minimum it may calculate.
- Likely cause
- A disconnected or faulty outdoor sensor or its wiring. NIBE’s VVM S320 manual places BT1 outside, in the shade, wired to the indoor module.
- 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. NIBE’s VVM S320 manual adds, for the same sensor fault, that the minimum flow temperature can be raised for the time being (menu 1.30.4 on that model) if the house is too cool, and to reset the alarm once the sensor connection is checked.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
71 Permanent communication error, base card
- What it means
- The controller has had no communication with the base card (circuit board AA2) for long enough that the alarm is permanent. The compressor is blocked, and the alarm needs a manual reset.
- Likely cause
- The list gives the lost communication only. Alarm 171 is the same break while it is still temporary.
- 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 alarm list says it needs a manual reset, and a break that comes back after a reset needs someone to find it.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
162 High condenser out
- What it means
- The water leaving the condenser — the heat exchanger where the heat pump hands its heat to the heating water — has reached the maximum permitted temperature. The alarm resets itself.
- Likely cause
- The list names the condition, not why it happened.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
163 High condenser in
- What it means
- The water coming back into the condenser is above its maximum temperature.
- Likely cause
- The list names the condition, not why it happened.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
183 Defrosting
- What it means
- Not a fault: a defrost is in progress. The list gives it no effect on operation and no action.
- Likely cause
- The list gives none beyond the defrost itself.
- What you can safely check
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.
- Wait for the defrost to finish: NIBE lists it only as “Defrosting in progress”.
- When to call an installer
- No call to your installer is needed for the defrost itself: the list gives no action for it.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
220 High pressure alarm
- What it means
- The outdoor unit is sending a high-pressure fault message to the controller. The compressor is blocked.
- Likely cause
- NIBE’s list gives this alarm the same cause line as 220 to 230: the outdoor unit is sending a fault message to the controller, which blocks the compressor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
221 Low pressure alarm
- What it means
- The outdoor unit is sending a low-pressure fault message to the controller. The compressor is blocked.
- Likely cause
- NIBE’s list gives this alarm the same cause line as 220 to 230: the outdoor unit is sending a fault message to the controller, which blocks the compressor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
223 Communication alarm
- What it means
- The outdoor unit is sending a communication fault message to the controller. The compressor is blocked.
- Likely cause
- NIBE’s list gives this alarm the same cause line as 220 to 230: the outdoor unit is sending a fault message to the controller, which blocks the compressor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
224 Fan error
- What it means
- The outdoor unit is sending a fan fault message to the controller. The compressor is blocked.
- Likely cause
- NIBE’s list gives this alarm the same cause line as 220 to 230: the outdoor unit is sending a fault message to the controller, which blocks the compressor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
228 Defrost fault
- What it means
- The outdoor unit is sending a defrost fault message to the controller. The compressor is blocked.
- Likely cause
- NIBE’s list gives this alarm the same cause line as 220 to 230: the outdoor unit is sending a fault message to the controller, which blocks the compressor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Try “Reset alarm” on the display once. If the alarm comes back, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
229 Short operation times for compressor
- What it means
- The compressor has stopped three times in a row a short time after starting, so the controller blocks it.
- Likely cause
- The list records the short runs, not why they happen.
- 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: repeated short runs are a fault to find, not to reset away.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
271 Cold outdoor air
- What it means
- The outdoor unit (EB101) is sending a message that the outdoor air is too cold, and the compressor is blocked.
- Likely cause
- Outdoor air colder than the outdoor unit works in, by the alarm’s name. The list gives no temperature.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer The list gives no owner action. If the alarm stays, call your installer.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
294 Not compatible heat pump
- What it means
- The outdoor unit connected to the VVM 320 is not one of the F2030-7, F2030-9, F2040-8 or F2040-12, or the DIP switches on its circuit board are set wrongly. Hot water is blocked, and the unit cannot be restarted after the power has been off.
- Likely cause
- A wrong outdoor unit model, or wrong DIP-switch settings on its circuit 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: it is a set-up fault on their side, and the alarm list says a restart after a power cut will not clear it.
Source: NIBE, Alarm List, NIBE products with Emmy display (version 1747-1, updated 2017-11-23): number, alarm, cause and heat pump operation Checked 2026-10-14.
A code that is not listed here
The list runs from 1 to past 400 and covers ground-source, exhaust-air and air-source products, so many numbers will never appear on yours: brine alarms such as 160 and 161 belong to ground-source heat pumps, 64 and 164 (low exhaust air temperature) to exhaust-air ones. Some numbers come in pairs: 170 to 178 mean communication with a circuit card is temporarily missing, and 70 to 78 mean the same break has become permanent, which needs a manual reset. If an alarm keeps coming back, the VVM S320 manual’s advice is to select “Auxiliary operation” (aid mode) and contact your installer: the installation then tries to make heat and hot water even though there is a problem, which can mean the compressor is not running and the electric additional heat does the work. The status lamp stays red, because the cause has not been put right.
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 these pages, published by NIBE 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.