Worcester 350 Combi User Manual

---- 1----~..
3
---- - NO NO
[
Does the pressure slowly increase
over the next minute '
YES
Does the fan switch to full speed
when the gas pressure exceeds
approximately 4.5 mbar?
YES
_.,. Does the vo ltag e on the white p in of _.,. Replace the driver board assembly.
terminal XS gradually fall towar ds
B VDC?
I YES
Replace the gas valve.
NO
_.,. Replace the driver board assembly .
NO
NO
Does the gas pres sure settle to _.,.
Remove the Mo le x plug from
terminal X11 . Measu re the
resista n ce as follows: betwee n
purp le and yellow pi ns-1 0 kohms,
between purple and pi nk
pins-between zero and 10 kohms
depending on the position of the
Temperature Con trol Knob . Is this
correct?
_.,. Replace the t emperature co n trol
main tain constan t water temperature
set by the Temperatu re Co n trol Knob
YES
NO
potentiomete r on the f acia
YES
_.,. R emo ve the Molex pl ug from
t erminal X2 .Is th ere a resistan ce of
1. 5 to 25 kohms a cross the brown
and yellow pins '
I YES
R eplace the driver board assemb ly.
NO
NO
_.,. Rep lace the ce n tral hea ting se n sm
NO
Gradually t um off the radiators one
by one so that the a pplia nce shuts
down as the system temperature
rises above the set leve l. Does the
STANDBY i ndic ator remain on ?
Hi gh lim it thermostat has activated . -...
Repeat the centr al he ating cycle .
Remove and insp ect the central _.,. Replace the driver board assembly .
[
Does t he voltage on the white pin of
terminal xs increase as the
temperature increases ?
YES
Replace the gas valve .
NO
Is there a 2 1fz minute ( approx.) de la y _.,. Replace the driver board assemb l y.
before the appliance re-starts?
I YES
End of central heating test Remove
the manometer. Reset t he appliance
and syste m contro l s.
37
h eating sensor . Is it badly scaled up?
YES
Re p lace the central heating sensor.

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English