FAQ - frequently asked questions about your heating equipment

Have you got a technical question about your heating equipment? - Your skilled Wolf customer service department is always there!

In addition, we have assembled the most frequently asked technical questions for you on this page to give you the best help possible in advance.


    • Why does the equipment keep heating through the night, or switch itself off completely?

    • In the weather-compensated heating controllers built from 1998 on, it is possible to switch the heater into a set-back mode at adjustable times. It must be borne in mind that even during the night time set-back, the base temperature cannot fall below 38 °C. If the flow temperature falls below 38 °C while the burner is operating, water condensation will result. This condensation attacks the metal components of the boiler. 

      Maintaining the base temperature can mean that when the external temperature is relatively mild, the forward flow is between 40 °C - 50 °C during the day, and that even during set-back operation, the room temperature does not drop noticeably, as a result of maintaining the base temperature. 

      The controller has a parameter (ECO/ABS), accessible to the service technician, through which an external temperature can be specified above which the regulator switches the equipment off entirely during the night. This is factory-set to 10 °C. This means that when the outside temperature is more than +10 °C, the regulator will switch the boiler off entirely during set-back operation. If the outside temperature falls below +10 °C, then the burner and the pump for the heating circuit will remain in operation, maintaining the minimum base temperature. 

      You can adjust this temperature to your own wishes, and can reduce it so that the controller will only enable the burner during the night time set-back period at colder outside temperatures. It is, however, necessary to note that at outside temperatures below +2 °C, the frost protection will come into play, keeping the pump in at least intermittent operation in order to stop the pipes from freezing. 

      You can read more about the adjustment options, along with other information, in the assembly instructions under the "ECO/ABS" topic.

    • It doesn't get properly warm in the house.

    • The controller is factory-set to a room temperature of 20 °C. This temperature can be adjusted, i.e. raised, in the controller. This will raise the entire temperature level, regardless of the outside temperature.  

      (See the "Day temperature" section in the assembly and operating instructions.) 

      If you have a remote control unit with room sensor, the room sensor, which is disabled at the factory, can be switched on, and the current room temperature included in the calculation of the flow temperature. 

      (See the "Room sensor" section in the assembly and operating instructions.)


    • The service water is not heated up on one (or more) day(s).

    • Please check your switching times. It is possible that one day has accidentally been deleted from the switching time. 

      (See the "Setting the switching times" section in the assembly and operating instructions.)

    • Error "22" occurs on combi boiler.

    • The display of an error message always flashes. If only the number appears on the display, it is not an error code, but is the flow temperature. 

      If the number 22 flashes, the air exhaust system should be checked for leaks. 

      On condensing units, please check the cleanliness of the condensate siphon, and clean it if necessary. 

      Check the heat exchanger, which must be cleaned if it is soiled.


    •  Error "7" occurs on your gas combi boiler.

    • Code "7" indicates that the exhaust temperature monitor has signalled. This can be caused by heavy soiling of the heat exchanger. 

      In condensing combi boilers it is also necessary to check the displacement body (heat exchanger insert), and to replace it if necessary. 

      The code "7" indicates escaping exhaust gas on conventional open combustion boilers. In this case the route for the exhaust and/or the chimney draught should be checked. 

      If these possibilities are found not to be the cause, the exhaust gas sensor/monitor must be replaced.

    • A circulation pump is connected to output "A1" of the condensing combi boiler, but switching times cannot be entered.

    • The freely parameterisable "A1" output must first be parameterised as an output for the circulation pump (see the section on the "Output A1" in the assembly and operating instructions).  

      Important: on devices with an integrated stratified storage, the output "A1" has already been factory-assigned to the charging pump. In this case it is not possible to connect a circulation pump to the "A1" output.


    •  A "BM" operating module and an "MM" mixer module are connected to the condensing combi boiler. However, only one slope can be set, although separate slopes are required for the heating and mixing circuits.

    • The configuration at the "MM" (Parameter "MI 05") must be set to heating circuit and mixing circuit (selection option 3). It is then necessary to totally remove power from the installation and to restart it.

    • Error "41" appears at conventional combi boilers.

    • The flow is monitored by the return and flow sensors. Error "41" appears if the value at the return sensor is more than 25 °C higher than the value of the flow sensor.  

      Please check the pressure (1.5 - 2 bar required) and the function of the heating circuit pump.  

      Take hold to the left and right next to the overflow valve, to check whether it opens.  

      If the heating circuit pump and the overflow valve are working, and if the pressure of the installation is within the required range, we recommend that the flow and return sensors are exchanged, since one of the two sensors may be sending incorrect temperature values to the controller.


    • Register or deregister sensors in the "WRS" Wolf control system

    • Carry out a master reset. First switch the equipment off at an on/off switch, press the fault clear button, and hold it down while switching the equipment back on. Hold the fault clear button down until the illuminated ring briefly lights up in all the colours (red, green, yellow). (See the "Sensor detection" section in the assembly and operating instructions.)

    • In the event of a fault, is it possible to bypass the exhaust gas sensor of a wall mounted boiler?

    • No, the sensor is an important safety component and cannot be bypassed. In the GB series of condensing devices, a flow or return sensor can be used as an alternative for a short time.