Worcester 350 Combi User Manual

NO
NO
Does the central heating pump run? ~ Does the dome stic hot water pump ~
YES
Is ther e 24V AC across the orange
and bl ack pins of terminal X2 ?
NO YES
run?
NO
I YES
..- Is there 36V DC at the black p in of
terminal XS '
YES
NO
Is there a live su pp ly on the brown
pin ofterminal X 19 ?
NO
~ Rep la ce t he driver boar d as sembly.
NO
Remove the p lated screw in the ~ Rep l ace the central hea ting pump .
ce n tre of the c entral heating pump
and turn the sh aft with a flat bl aded
screwdriver. Does the centra l
heating p ump no w run ?
YES
Replace the transformer.
Is there less tha n 2V DC on the
wh i te pin of terminal XB ?
~ Replace the driver board
assemb ly.
Replace the driver board assembly.
Re pl ace th e ignit i on board .
YES
Does the fan start up at high speed ? (fo check this, it may be n ecessa ry to m easure the
voltage across the fan terminals wh ich should be 240V AC for two seconds.
Note : The gas supply must be tu rned off du r ing this tes t) .
YES
NO
Does the fan start up at low speed
onl y?
Monitor the pink pin on terminal XS
and restart the appliance again.
Doe s the vo l tage ever reach 36V DC?
NO YES
Rep lac e the driver board
assembly
Replace the ignition board.
R eplace the driver board assembly.
NO
~ Check th at the appliance is not in
an anticyde de lay by switchin g the
Operating Switch OFF - ON .
Rep la ce the air pressure switch .
I
Repair t he fault.
NO
.._ Is t he re less than 2V DC on the red
p in of t erminal XB ?
1
YES
YES
Is there 39V DC on the ora n ge pin of ~ Rep l ace the ignit i on board.
terminal XB ?
----
NO
~
NO
.._
YES
35
F ree the f an if stuc k or r eplace the
fan.
I YES
Is there an y AC vo ltage acro ss th e
fan terminal s?
NO
Is there a li ve supply to the grey pin
ofterminal XB ?
YES NO
NO
~ Is t he re a live supp ly on the
green pin of term inal X21 ?
.....----~' YES
l
Is there a live supply on the wh i te
pin ofterminal X21 ?
INC
YES
Check the supply pipes to the air
pressure switch fo r correct routing an d
condition . Has damage occurred?
Repl a ce the i gnition board .
YES
Repla ce fuse F2 . If it blows
ag ain replace the ignition
boar d.
Is there an BV DC on the
orang e pin of term inal XS?
Remove the Molex plug from
terminal X12 .1s t he re a resis tance
of 1.5 to 25 k ohms across t he
brown and y ellow wires?
NO YES
Rep la ce the c entral heating
sensor.
Rep l ace the transformer. ..- Remove the Mole x plug from
termin al X2 . Is there an op en circui t
betwee n the brown and blue wires
NO or between t he orange a nd black
Replace the drive r board assembly. ..- wires?
------------------

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English