Technical data
49
Troubleshooting 8
Instructions for installation and servicing ecoMAX
49
Key to Fault codes
Code Meaning Cause
F.0 Flow–NTC:
– NTC broken
– NTC cable broken Flow–NTC cable defective/broken NTC faulty
– Defective connection at NTC
– Defective connection at electronics
F.1 Return–NTC:
– NTC broken
– NTC cable broken Return–NTC cable defective/broken NTC faulty
– Defective connection at NTC
– Defective connection at electronics
F.10 Short circuit – flow–NTC (< 130 °C) NTC– plug shorted to casing, NTC defective
F.11 Short circuit – return–NTC (< 130 °C) NTC– plug shorted to casing
NTC defective
F.13 Short circuit in tank sensor NTC defective, earth leak/short circuit in cable loom,
damp plug connection
F.20 Over heat cut off activated  Maximum temperature exceeded
No water in system
F.22 Low water or no water in appliance Pump defective
Pump lead defective
F.23 Water level low Pump obstructed, pump running at lower capacity,
Temperature range too wide Air in appliance, system pressure too low,
flow and backflow NTC reversed
F.24 Water level low Pump obstructed, pump running at lower capacity,
Temperature rises too fast ir in appliance, system pressure too low,
flow and backflow NTC reversed
F.25 Water Switch Water Switch - plug disconnected
System pressure too low Waterswitch activated
F.27 No demand to gas valve Electronic board defective
Gas valve defective 
No gas
Insufficient gas 
Incorrect gas valve adjustment 
F.28 Boiler goes to lock out Electrode defective
Ignition lead defect
Electronic igniter defective
Check air inlet duct
F.29 Flame extinguished re–ignition unsuccessful Gas supply absent or insufficient
Check flue duct
F.32 Fan turning–speed malfunction Fan unit obstructed, plug–in fan connector not 
(too fast at start–up) correctly inserted, Hall sensor defective, fault in cable 
loom, defective electronic control system
F.60 Gas–valve control + defective Short circuit/earth (ground) leak in cable loom to gas 
valves, gas valve assembly defective (earth/ground 
leak from coils), electronic control system defective
Short circuit/earth (ground) leak in cable loom to gas 
F.61 Gas–valve control – defective valves, gas valve assembly defective (earth/ground 
leak from coils), electronic control system defective
F.62 Defective gas–valve closure mechanism Leak in gas valve assembly, electronic fault
F.63 EEPROM error Electronic fault
F.64 Electronic system/sensor fault Short circuit in flow or backflow NTC, 
electronic fault
F.65 Electronic system temperature too high Electronic system affected by external heat source,
electronic fault
F.67 Electronic fault in flame system Electronic fault
(non–plausible flame signal)
Table 8.3 
83 41 77_12 GB04.04.qxd 22.09.2004 12:34 Uhr Seite 49










