Inventum heat pump faults: fault codes, causes and parts

Q: What does a fault on an Inventum heat pump mean?

The appliance is reporting that it has shut itself down or cannot continue. The code on the display points to the group of causes: ignition, water pressure, a sensor, the fan or communication with the thermostat. The table above shows, for each code, what Inventum means by it.

Q: How do I reset my Inventum heat pump?

The reset button is on the control panel of your Inventum heat pump; on most appliances you hold it down for two to five seconds until the display responds. Reset once. If the same fault comes straight back, resetting will not solve it and a part or a setting needs attention. Always consult the manual for your model: the position of the button and how long to press it differ per series.

Q: Can I fix an Inventum fault myself?

You can top up the water pressure, bleed the system, replace filters and clean a siphon yourself. Anything behind the sealed section of a gas appliance is a different matter: work on the gas valve, burner, heat exchanger and flue must be carried out by a certified gas engineer.

Q: How much does it cost to fix a fault?

That depends on the cause and whether a part is needed. With us you can see the part straight away with its price and delivery time, so you know where you stand in advance. If you call in an engineer, always ask about the call-out charge and hourly rate before they come.

Q: Where can I find the right part for my Inventum?

Check the rating plate for the exact type and use it to search our catalogue, or search directly by the manufacturer number of the faulty part. Each part lists the appliances it fits.

All 84 fault codes for Inventum heat pumps, plus the faults that show no code. Type your code or choose your symptom.

In brief

A fault on an Inventum heat pump usually means that the appliance has locked out or is reporting a fault code. Note the code on the display and look it up below: for each code you will find its meaning, checks you can safely do yourself and the parts that are often checked or replaced. Frequently searched: 94 (error code 81 repeated within 24 hours), 95 (water pressure is critically low (< 0), F-94 (air in the system, pump defective, condenser…). No code? Check the power supply, the settings and the filters, and reset once. If the fault comes back, call in a qualified professional.

Most searched Inventum faults

These are the codes that visitors to this site search for most often.

94Error code 81 repeated within 24 hours.…95Water pressure is critically low (< 0.3…F-94Air in the system, pump defective, condenser…70Water pressure sensor error 71Flow-through heater protection active (HP function remains…90Compressor locked out (repeated error 80)81No temperature difference across the evaporator F-02Fan emergency operation

See the 25 most searched fault codes of 2026, with the figures behind them →

Inventum heat pump faults without a code on the display

Not every fault shows a code. These are the symptoms we come across most often with Inventum appliances, with what you can check yourself before calling someone out.

Heat pump no longer produces heat

Check that the system has enough pressure and whether there is a message on the display or in the app. After a power cut, some units start up in a safe mode and have to be released manually. View the matching parts → Read also: heat pump freezes or defrosts constantly →

Outdoor unit freezes or defrosts constantly

A thin layer of ice in frosty weather is normal; the unit defrosts itself periodically. If the ice stays or the unit defrosts every few minutes, the airflow is obstructed or something is wrong with the defrost control. View the matching parts → Read also: heat pump freezes or defrosts constantly →

Too little or too cold hot water

Check the set hot water temperature and whether the electric immersion heater is enabled. A sharp drop in hot water capacity often points to a faulty cylinder sensor or a worn anode in the tank. View the matching parts → Read also: replace the anode before the tank fails →

Noise or vibrations

A noticeably louder noise than normal usually comes from the fan or from vibrations carried through the pipework. Check that the unit stands clear and that the anti-vibration mounts are intact. View the matching parts → Read also: noise and ice on the outdoor unit →

All 84 Inventum heat pump fault codes

Code	Cause
10	Low water pressure (< 0.8 bar)
10	The controller detects a heating system or water pressure that is too low.
11	Filter replacement timer has expired
12	No communication with room thermostat
12	No communication with the room thermostat
13	No communication with boiler
20	Replace the filter!
30	Boiler upper over-temperature sensor error
31	Boiler lower under-temperature sensor error
32	Flow-through heater temperature sensor error
33	Air-in GCM sensor error
34	Air-out GCM sensor error
35	Air flow GCM sensor error
36	GCM frost protection active
37	Connection with GCM lost
38	No valid setpoint GreenComfort Module
51	Air-in sensor error
51	Air-in sensor error
52	Air-out sensor error
52	Air-out sensor error
53	Evaporator sensor error
53	Evaporator sensor error
54	Heating return sensor error
54	Heating return sensor error
55	Heating flow sensor error
55	Heating flow sensor error
56	Hot gas sensor error
56	Hot gas sensor error
60	Modul-AIR air flow sensor error
60	Air flow sensor error
70	Water pressure sensor error
70	Water pressure sensor error
71	Flow-through heater protection active (HP function remains active)
80	No temperature difference across the condenser, heating side
80	No temperature difference across the condenser
81	No temperature difference across the evaporator
81	No temperature difference across the evaporator
90	Compressor locked out (repeated error 80)
90	Error code 80 repeated within 24 hours. Compressor locked out
94	Error code 81 repeated within 24 hours. Compressor locked out
94	Compressor locked out (repeated error 81)
95	Water pressure is critically low (< 0.3 bar).
95	Water pressure is critically low (<0.3 bar)
AP-1 (geen fault)	Hot gas protection active
AP-2 (geen fault)	Discharge gas protection active
AP-3 (geen fault)	Freeze protection gas protection active
AP-4 (geen fault)	Ventilation heat pump in operation for the 2nd time within 15 minutes
AP1 (geen fault)	Hot gas protection active
AP2 (geen fault)	The average heating temperature is higher than 60°C
AP2 (geen fault)	The average heating temperature is higher than 60 degrees
AP3 (geen fault)	Freeze protection is active
AP3 (geen fault)	Freeze protection active
AP4 (geen fault)	Pause mode. The compressor may not be started yet.
AP4 (geen fault)	Pause mode, compressor may not be started
F-01	Pump emergency operation
F-02	Fan emergency operation
F-03	Compressor emergency operation
F-04	Boiler emergency operation
F-05	Heating demand emergency operation
F-50	Error identification code measured value out of range (-20 °C to 140 °C)
F-51	Air-in
F-52	Air-out emergency operation
F-53	Suction gas
F-54	Hot gas
F-55	Return temperature error
F-56	Flow temperature error
F-57	Boiler temperature error
F-59	Supply temperature sensor error
F-80	Drying-out protection active, air in the system, flow and/or return sensor defective and/or pump defective
F-81	Internal compressor protection open, compressor overloaded
F-90	Possible capacitor defect
F-93	Hot gas and discharge gas cannot both be determined
F-94	Air in the system, pump defective, condenser or compressor defective
Filter change alarm	Filter must be replaced
HP alarmcirculatie	Connector not connected properly
High gasdruk alarm	Gas pressure above 42 bar
Inverter alarm	Power cable connector not connected properly, fault in inverter, fault in compressor
Klok niet ingesteld	Clock not set during commissioning
Low pressure 1 alarm	TE6 measures evaporation temperature lower than - 23 °C
Low pressure 2 alarm	Pressure below 1.5 bar
Max. therm. verw. Element alarm	Maximum temperature protection has been triggered
SD geheugenkaart fout	Memory card missing or defective
UIT	Compressor switched off by the ventilation speed switch, position 0, or the night timer switch is on
Waarschuwing koeling alarm	Compressor stopped due to maximum temperature being exceeded during cooling

Order parts for your Inventum heat pump

Inventum parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.

View Inventum parts →

Frequently asked questions about Inventum faults

What does a fault on an Inventum heat pump mean?

The appliance is reporting that it has shut itself down or cannot continue. The code on the display points to the group of causes: ignition, water pressure, a sensor, the fan or communication with the thermostat. The table above shows, for each code, what Inventum means by it.

How do I reset my Inventum heat pump?

The reset button is on the control panel of your Inventum heat pump; on most appliances you hold it down for two to five seconds until the display responds. Reset once. If the same fault comes straight back, resetting will not solve it and a part or a setting needs attention. Always consult the manual for your model: the position of the button and how long to press it differ per series.

Can I fix an Inventum fault myself?

You can top up the water pressure, bleed the system, replace filters and clean a siphon yourself. Anything behind the sealed section of a gas appliance is a different matter: work on the gas valve, burner, heat exchanger and flue must be carried out by a certified gas engineer.

How much does it cost to fix a fault?

That depends on the cause and whether a part is needed. With us you can see the part straight away with its price and delivery time, so you know where you stand in advance. If you call in an engineer, always ask about the call-out charge and hourly rate before they come.

Where can I find the right part for my Inventum?

Check the rating plate for the exact type and use it to search our catalogue, or search directly by the manufacturer number of the faulty part. Each part lists the appliances it fits.