Worcester Combi RSF 240 Installation And Servicing Instructions page 36

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START OF DOMESTIC HOT WATER TEST
Set the Operating Switch (or
programmer) to
WATER.
lllrn a
domestic hot water tap on fully.
Does the
DEMAND
indicator
illuminate?
YES
Does the pump run?
NO
__.. Is the
STANDBY
indicator still
illuminated?
YES
Is there a 240V supply at pin 2 on
terminal
X1 0?
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YES
Is there a 240V supply at pin 3 on
terminal
X3?
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YES
Replace the
DEMAND
indicator.
NO
__.. Refer to section
STANDBY Indicator
light does not illuminate.
NO
__.. Replace the Operating Switch (or
programmer) .
NO
__.. Is the flow rate greater than
2.6litres/min?
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YES
Replace the flow switch.
NO NO
__.. Is there a 240V supply at pin 2 on __.. Replace the pump overrun
NO
__.. Investigate and rectify low flow rate.
- - - . - - - - - - - - terminalXS? thermostat.
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YES NO - - - - - - -
YES
YES
Does an automatic start-up
sequence occur, ending in full
burner ignition
YES
NO
Does the fan run?
NO
Remove the plated screw in the
centre of the pump and turn the
shaft with a flat bladed screwdriver.
Does the pump now run?
__.. Does the fan run, then stop, then
- - - . - - - - - run etc ... ?
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YES
Replace the sequence board.
36
__.. Replace the pump.
NO
__.. Is there approximately 24V AC
across the test pins on the main
driver board?
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YES
NO
__.. The transformer is faulty. Replace the
main driver board.
NO
Is there a 240V supply at pin 1 on __.. Remove the Centre Molex plug from
terminal
XB?
terminal
X2.
Is the domestic hot
water sensor resistance between
YES
!
, - -----
1 .5 and 25 kohms across the red
YES
wires?
- • .-NO _ _ _ _ _
Replace main driver board.
Is there a 240V supply at pin Lon
terminal
CN1?
YES
6
NO
Check the connections on the
domestic hot water se.tsor or
replace the sensor.
~ Check or replace the overheat
thermostat.