Fault Codes; Fault Finding - Vaillant ecoMAX pro 18 E Instructions For Use Installation And Servicing

17 Fault finding

17.3 Fault Codes

Fault codes take priority over all other display functions
in the event of a system fault occurring.
Code Description
F1 Ignition fault (lockout)
Failed to light
F4 Ignition fault (lockout)
Went out when lit
F5 Overheat fault
F6 Central heating flow NTC fault
F10 Central heating return NTC fault
F11 No reception by main board
F12 No reception by the local user interface
F13 Main board fault
F14 Central heating flow t° > 95° C
F16 Flame detection fault
(flame presence >5 s after burner stop)
F17 Power supply <170 V
F18 Local user interface fault
F19 Central heating NTC unplugged
F20 MMI software incompatible with IRIS software
F24 Central heating return t° >90°C
F25 Maximum temperature rise slope
F26 Maximum delta t
32
Comment
No gas; Insufficient gas; Incorrect gas valve adjustment; Electrode defect;
Ignition lead defect; Electronic igniter defective; Check air inlet duct;
Check connections to igniter unit
As above
Overheat stat operated; Maximum temperature exceeded;
Check thermistor connections; Air in system with thermistor at maximum
setting; Faulty overheat stat connection; Check that pump is wired into
appliance and not from programmer. This would cause no pump overrun
Flow NTC cable defective/broken NTC faulty
Flow thermistor not fitted correctly, Check pipe work configeration
Return NTC cable defective/broken NTC faulty
Check that thermistor attached correctly to pipe.
Connection fault between main PCB and interface; Faulty interface;
Faulty main PCB (processor), Check fan
As F.11
As F.11
System fault; Possible external pump failure; Check NTC on flow
Check that pump is wired into appliance and not from programmer.
This would cause no pump overrun
Gas valve defective
Check electrical supply / polarity, Check fan
Connections; Faulty interface
Check NTC connection
Possible connection fault
System fault; Possible external pump failure; Check NTC on return;
Check that pump is wired into appliance and not from programmer.
This would cause no pump overrun.
Possible external pump failure; Air in system restricting movement of water.
Insufficient circuit flow
Check NTC on return; System fault – too restrictive?; Possible pump failure
Instructions for Use, Installation and Servicing ecoMAX pro