Worcester Highflow 400 RSF Installation And Servicing Instructions page 47

Disconnect the room thermostat and frost thermostat if fitted,
note the positions.
Disconnect the mains supply at the terminal strip located
bottom left hand corner of the control board, marked X11
'Mains Supply'. Unplug the Operating Switch or programmer if
fitted, from terminal marked X12 ''Programmer/Switch''.
Release the plastic catch at each mounting post pulling the
printed circuit board forward approximately 3 mm to prevent the
plastic catch from returning. Pull the board off the remainder of
the mounting post until it is free. Discard the board.
Locate the new board over the four mounting posts and push
back squarely until the plastic catch on the end of each post
clicks into place.
Reassemble in the reverse order and ensure that :
i) the mains supply, room and frost thermostat are
connected correctly.
ii) the Operating Switch or programmer is plugged into the
terminal strip.
iii) the Molex connectors are fitted to the correct terminals.
Connectors are not interchangeable and will only fit the
terminals from which they were removed.
Refer to the wiring diagram. Fig. 9 Reassemble the facia in the
reverse order.
36. Ignition Board. See Figs. 9 and 53.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position as described in Section 14.2 a and b.
Remove the facia as described in Section 15.1.
Carefully pull off all the Molex plugs, note the positions.
Ease the spark electrode lead off the connection at the top right
hand corner of the ignition board. Release the plastic catch at
each mounting post pulling the printed circuit board forward
approximately 3 mm to prevent the plastic catch from returning.
Pull the board off the remainder of the mounting post until it is
free. Discard the board.
Locate the new board over the four mounting posts and push
back squarely until the plastic catch on the end of each post
clicks into place.
Fig. 53. Control Box.
Thermostat mounting bracket
Hot water
thermostat
Hot water high limit thermostat.
Unscrew the central clamping nut
and remove from the control box.
Neon indicator lights connected to
terminal X3 (marked ÒIndicatorsÓ).
Heating
thermostat
Control board
Reassemble in the reverse order and ensure that :
i) the spark electrode lead is connected to the terminal at
the top right hand corner of the ignition board.
ii) the Molex connectors are fitted to the correct terminals.
Connectors are not interchangeable and will only fit the
terminals from which they were removed.
Refer to the wiring diagram Fig. 9. Reassemble the facia in the
reverse order.
37. Facia Mounted Programmer. See Fig. 9 and 16.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position as described in Section 14.2 a and b.
Remove the facia as described in Section 15.1.
Unplug the programmer from the control board terminals
marked X12 ''Programmer/Switch''. Undo the four nuts securing
the programmer to the facia and remove. Fit a new programmer
in the reverse order and connect the plug at the driver board.
Reassemble the facia in the reverse order.
38. Remote Mounted Programmer. See Fig. 9.
Check that the electricity has been turned off and isolate the
programmer.
Disconnect the leads from the programmer noting their
alignment. Fit the replacement programmer and reconnect the
leads checking that they are correctly positioned.
39. Neon Indicator Lights. See Figs. 9, 53, 55 and 56.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position as described in Section 14.2 a and b.
Remove the facia as described in Section 15.1.
Unplug the neon connection at terminal X3 (marked
"Indicators") on the control board. Use an electrical screwdriver
to carefully push down through the locking clip slot to depress
the locking clips and withdraw the appropriate leads of the failed
neon.
Remove the neon from the facia panel.
Push the replacement neon into the facia panel. Insert the new
neon leads into the plug with the locking clip in the correct
position.
Reconnect the plug to the control board referring to the wiring
diagram Fig. 9.
Reassemble the facia in the reverse order.
Ignition board
Safety temperature limiter
thermostat. Unscrew the central
clamping nut and remove from
the control box.
47
Air flow pressure
switch
Control
box