Worcester 350 Combi User Manual

----:r NO
NO
Does the fan drop to low speed after ____.. Does the fan remain at high speed ?
____.. Replace the fan r esistor.
two seconds at high speed' (240 V AC across fan terminals .)
(165V AC across fan terminals .)
1 ~s
YES
____.. Replace the driver board assembly .
YES
NO
Replace the i gn iti on board ? ...__ Is there more than 30V DC on the
pi nk pin of the terminal XS ?
NO
NO NO
Does sparking occur? N ote . If the ____.. Is there a live supp ly on all three
____.. Check the supply pipeS to the air ____.. Replace th e air pressu re switch .
applian ce is very co ld, sparking ma y pins of terminal X21 ?
pressure switch for correct routing
and condition . Has damage occurred?
I YES
be delayed .
YES
YES
Repair the fault.
Replac e the igni tion board .
Check for a short circuit on the
YES electrode lead or electrode and rectify NO J
~--------- asnecessary . Isthereanyspark? ---------------....J-
[
NO
Is there any flame within the burner? ____.. Is there a live supply to both brown
pins of the terminal X2 2 during the I
YES sparking period?
NO ..___I ___ ____...~
YES
____.. Replace the gas valve. Replace the i gnition board.
[
00 00 00
Does the flame continue after the
sparkin g stops?
____.. This causes a ' lockout' condition. ____.. Check the flame sensor electrode and ____.. Rep lace the ign ition board.
Investigate and rectify the burner jets, l ead for condition and setting . Does
YES
gas valve and gas supply . Restart the the flame continue?
appliance. Does the flame continue ?
YES
NO
1\Jm off the appliance and connect a ___. Does the boiler shut down rapidl y?
manometer to the burner pressure
test point. W ith the h eatin g S}'Stem YES
cold restart the heating cycle . Does
the gas pressure stay at 1.3 mbar for
approximately two minutes?
YES
Pump does not circula te the water
Bleed air or dear blockage in the
1---------- system. Does the gas stay at 1.3 mbar
YES
for approximately two minutes ?
YES
NO
___. Does the gas pressure gradu ally
YES
increase from the beginnin g of the
demand?
Replace the driver board assembly.
Remove the Molex pl ug from terminal ___. Replace the driver board assem bl y.
NO
___. Pressure immediately jumps to a
hig h value. Is there 21 to 2 5V DC on
the white pin of terminal xs durin g
the in i tial two minute period?
I NO YE S I
Replace the gas valve .
Replace the central heating sensoL
3 ----
X12 .Is there a resistance of 1 .5 to 25 t
kohms acrcss the brown and yellow NO
pins ? - --------------~
36

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English