DOMINA 80 E
54
8.03 MF02 PCB
When operating for C.H. the following lights should be on: 1, 3 and flame on light. for D.H.W. the following
lights should be on: 1, 2, and flame on light.
If the boiler works for C.H. but not D.H.W., or vice versa, a number of components must be functioning
and can, therefore, be eliminated as being at fault.
Boiler will not light for D.H.W.
If boiler works for C.H. but not for D.H.W. the fault is most likely to be the flow meter or D.H.W. sensor.
If the tap symbol light is on the fault is the D.H.W. sensor. If this light is not on then suspect the flow meter
has not operated.
Boiler will not light for C.H.
If the boiler works for D.H.W. but not for heating the fault is most likely to be external controls (i.e. clocks
or room thermostats). Integral clock if fitted or C.H. sensor.
If the heating demand light is on the fault is most likely the C.H. sensor. If this light is not on suspect either
a clock or room thermostat not calling.
To override/eliminate any external controls disconnect them from terminal 4 and 5 underneath the boiler
and refit the link wire (see fig. 31).
Boiler will not light for D.H.W. or C.H.
The fault is likely to be a component common to both services. Open a hot tap to create a demand - is there
a spark at the ignition electrode?
Yes
Suspect gas supply, pressure or gas valve.
No
Is fan running?
Yes
Suspect air pressure switch or overheat stat (if boiler lockes out without sparking go to overheat stat)
No
Is low water pressure light on?
Yes
Top up water to above 1 bar. Does the light go out? (if water pressure o/k suspect high limit stat)
Yes
Does fan start?
Yes
Does boiler light?
Yes
Is hot water OK?
Try heating, if heating does not work follow guide for heating faults. Does low water pressure light
go out?
No
Suspect low water pressure switch.
If boiler still does not fire see comprehensive fault finding chart.
