10.3.2 Error codes
Error code
Cause
Rectification
F11
Temperature at eSTL > 105 °C
▶
Check the water flow.
▶
Check function of the pumps.
▶
Check parameter A32.
▶
Vent boiler on the water side.
F15
Temperature differential between flow and return
too high (see also
W15
)
▶
Check function of pump, if necessary increase
pump rating.
▶
Check parameter A32.
▶
Safeguard system circulation.
F18
Difference eSTL and flow temperature too great
(see also
W18
)
▶
Check function of the pumps.
▶
Check parameter A32.
▶
Safeguard system circulation.
F21
No flame formation when the burner starts
(see also
W21
)
▶
Check the ignition unit and replace if neces-
sary.
▶
Check gas combi valve and cable and replace
if necessary.
▶
Check setting of gas combi valve.
▶
Clean or replace burner tube (see Ch. 9.5).
▶
Check phase of voltage supply.
F23
Flame simulation
▶
Check earth connections.
▶
Install mains filter.
▶
Check burner tube and ionisation electrode
(short circuit).
▶
Reset appliance, replace WCM-CPU on re-
peat occurrence.
F30
eSTL defective
▶
Check the sensor and cable and replace if
necessary.
F31
Flue gas sensor is defective
▶
Check the sensor and cable and replace if
necessary.
F32
Switch contact of air pressure switch not in
Standby
▶
Check air pressure switch and cable and re-
place if necessary.
▶
Chimney draught too great.
F35
The supply sensor is defective
▶
Check the sensor and cable and replace if
necessary.
F36
Water pressure insufficient
▶
Check system pressure and top up.
F37
return sensor defective
▶
Check the sensor and cable and replace if
necessary.
F38
Flue gas pressure switch does not drop out dur-
ing the fan standby check
▶
Check flue gas pressure switch and cable, if
necessary replace.
F41
Gas valve (internal) leaking
▶
Replace gas combi valve.
F43
Specified fan speed is not achieved
▶
Check the fan and cable and replace if neces-
sary.
F44
Fan standby defective
▶
Check fan and replace if necessary.
F45
Air pressure switch does not switch
(on/off pressure 1.0/0.7 mbar)
▶
Check flue gas ducting and air supply.
▶
Check air pressure switch and cable and re-
place if necessary.
▶
Clean burner tube (see Ch. 9.5).
F46
Flue gas side pressure too high
(release pressure 5.5 mbar)
▶
Check flue gas ducting.
▶
Check flue gas pressure switch and cable, if
necessary replace.
F48
Maximum run time of flue gas damper exceeded
(see installation instructions WAL-PP)
▶
Check flue gas damper and cable, if necessary
replace.
Installation and operating instruction
Gas condensing boiler WTC-GB 90-A
10 Troubleshooting
83266502 • 1/2010-08 • La
76-95
