92 3064810_201804
41.Troubleshooting
Fault
code
Fault Possiblecauses Remedy
12 Boiler sensor faulty Excesstemperatureintheow
Boiler sensor > 100 °C
Boiler sensor or sensor lead has short
circuit or break
Pump:
- Check if pump is running. If not, check
cables and plugs. If electrical connection
OK and no function, replace pump.
Excess flow temperature:
- Increase the minimum pump speed.
Boiler sensor:
- Check leads and plug-in connections.
- If OK and no function, replace the boiler
sensor.
Press reset button.
13 Flue gas sensor faulty Flue gas sensor or sensor lead has
short circuit or break
Flue gas temperature sensor:
- Check leads and plug-in connections.
- If electrical connection OK and no func-
tion: Replace the sensor.
Press reset button.
14 DHW sensor faulty DHW sensor (cylinder sensor) or sensor
lead has short circuit or break
DHW-sensor > 99 °C
DHW temperature sensor:
- Check leads and plug-in connections.
- If OK, replace sensor.
Press reset button.
15 Outside sensor faulty Outside sensor or sensor lead has short
circuit or break
eBus - Outside temperature sensor
Funk - Outside temperature sensor
eBus - Outside temperature sensor:
- See instructions for eBUS outside sensor.
Wireless outside sensor
- See instructions for wireless outside sen-
sor.
Press reset button.
16 Return sensor faulty Return sensor or sensor lead has short
circuit or break
Return sensor > 100 °C
Return sensor:
- Check leads and plug-in connections.
- If OK and no function, replace the return
sensor.
Press reset button.
20 GCV relay test Valve test failed
Gas valve faulty
Replace gas valve.
Press reset button.
24 Fan speed < Set fan speed is not achieved
Control unit casing not engaged
Fan faulty
F2 fuse defective on HCM-2
Fan:
- Check cables, plug-in connections, power
supply and switching.
- If OK and no function: Replace the fan.
Control unit casing not engaged
- Check that control unit top and bottom
casings are engaged.
Check F2 fuse on HCM-2 control PCB
Press reset button.
26 Fan speed > The fan does not stop Fan:
- Check cables, plug-in connections, power
supply and switching.
- If the fault occurs repeatedly, replace fan.
Press reset button.
27 DHW outlet sensor faulty
Straticationsensor
faulty
DHWoutletsensorfaulty/stratication
sensor or sensor lead has a short circuit
or lead break
DHW outlet sensor / stratification sensor:
- Check cables and plug-in connections.
- If OK and no function, replace the sensor.