50
Does sparking star
t?
Go to sheet .H
Does yellow ignition indicator
( ) flash after 30s?
Replace electronic boards.
Check operation of dif
ferential pressure switch
Sheet F
Has system been filled with
water?
Is solenoid activated?
Is differential pressure switch
activated?
Check for dir
t or damage to
the differential switch, supply
tubes and diaphragm.
Go to sheet G.
Ye
s
Ye
s
No
Ye
s
No
No
No
Ye
s
Fill and vent system and
boiler
.
No
Check continuity of
microswitch. Replace if
necessar
y.
Check connection
of ribbon plug to switch board.
If bur
ner still fails to light,
replace electronic boards.
Ye
s
