Worcester Combi RSF 240 Installation And Servicing Instructions page 35

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Does the gas pressure settle to
maintain a constant flow
temperature set by the temperature
control potentiometer? (If the
burner pressure is correctly
balanced to the system load).
YES
Gradually turn off the radiators one
by one so that the burner shuts
down as the system temperature
rises above the set level.Does the
output drive at pin 1 on terminal
XS
drop from 240V to OV during the
shutdown?
YES
Is there a 2·3 minute delay before
the appliance restarts?
YES
End of central heating test. Reset
the appliance and system controls.
NO
~ Remove the Molex plug from
terminal
X1.
Measure the resistance
as follows: Between purple and
yellow pins · 1 0 kohms between
purple and pink pins · between zero
and 10 kohms depending on the
setting of the temperature control
potentiometer. Is this correct?
I
YES
NO
~ Replace the temperature control
potentiometer on the facia panel.
NO
Remove the left hand Molex plug ~ Replace the central heating sensor.
from terminal X2.1s there a
resistance of between 1.5 and 25
kohms across the two white pins? I
YES
Replace the main driver board.
The overheat thermostat has
N 0
activated. Has the voltage across
~ the Modureg terminals dropped
below 5Vdc? (Reset thermostat).
Replace the Modureg.
NO
~ Replace the main driver board.
35
NO