52
Does yellow flame indicator
( ) glow and flames increase
in size to full rate?
Does bur
ner flame modulate/
go out when maximum
radiator temperature control
is tur
ned down to position 1
at a flow temperature of
approx. 50 degree C?
Check potentiometer for
par
tial load setting (see 5.9
C.H. range rating).
Pull of cable from NTC and
shor
t-circuit to ear
th. Is flame
extinguished?
Check operation of bur
ner and modulation
Sheet H
Check plug-in connections
to modulating solenoid.
Replace modulating regulator
of gas valve if bur
ner still fails
to increase to full rate.
Ye
s
No
No
No
Replace electronic boards.
Go to sheet J.
Ye
s
Is flame extinguished after
2nd ignition attempt, and red
lockout indicator ( ) lit?
Is flame visible prior to
lockout condition?
Check gas supply is live and
purged.
Check connections/operation
of both solenoids, replace gas
valve as necessar
y.
Ye
s
No
No
Check/clean bur
ner
,
ionization sensor and cable
for defects, good contacts
and correct position.
Check air/flue gas system is
correctly fitted and not
obstructed. If lockout occurs
replace electronic boards.
Ye
s