Certikin MB20S, Operating, Installation And Servicing Instructions

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5.0 Fault fi nding
31
Genie S
“GAS” will not clear
in standby
“GAS” will clear in standby but
returns during operation
Does fan run?
Wiring connections
OK?
Does heater reach ignition
stage (can a spark be heard)?
Yes
No
Replace fan
Yes
No
Yes
Does fl ame ignition take place
(see fl ame in sight glass) but
goes out after 10s?
Yes
Gas released by gas
valve (coils both ener-
gised)?
Is appliance earthing, ignition
lead and electrode OK?
No
Yes
“Gas” Lockout oc-
curs after ignition
attempt with no re-
tries
No
Replace ESYS
Is ignition lead and
spark gap OK?
Yes
Replace ESYS
Yes
Replace ESYS
Yes
Replace Gas valve
No
No
Replace Ignition lead and
electrode
Have the fl ue gas or fl ow tem-
perature limit switches triggered?
With power isolated,
reset overheat de-
vices
Yes No
Fault cleared?
Are connections
and wiring be-
tween ESYS &
limit devices OK?
R e p l a c e
c o n n e c t o r
or wiring
No
Yes
Investigate
causes of
overheating
No
Yes
Replace ESYS
NB - A “Gas” lockout which occurs
when there is no demand for heating
can only be related to the two manual
overheat protection devices. These are
constantly monitored by the controller,
even in standby mode.
NB - All non-overheat protection type
faults are only monitored during the igni-
tion process, and will occur at the end of
the fi rst 10s spark ignition period.
5.3 FAULT CODES & DIAGNOSTICS (CONTINUED)