IS 681 ECN 4301
Page 11 of 20
DRAIN VALVE
Remove the drain valve handle
Undo the four screws holding the switch panel and support under the drain valve.
Remove the drain valve extension assembly.
Unscrew the drain valve from the unit.
Remove the outlet stub pipe from the drain valve.
Reassemble in reverse order using standard practice for the sealing of the threads.
SYSTEM PCB
Undo the control panel (see above).
Remove the right hand side panel by unscrewing the fasteners at the rear, prising
the side panel from the rear, then sliding forward until clear of the front frame.
Identify, then remove all connections. Remove the two fasteners holding the PCB
bracket.
Withdraw the PCB assembly then undo the M4 nuts to allow removal of the PCB.
Reassemble in reverse order.
AIR/GAS RATIO VALVE
Follow the instructions above for the removal of the right hand side panel.
Remove the fasteners holding the left hand side panel. Remove the back panel.
Undo the four screws on the gas inlet flange, taking care not to lose the o-ring seal.
Undo the earth lead and the connector from the gas valve.
Undo the three torx T25
screws to the right of the fan air intake venturi and remove
the gas valve assembly.
Reassemble in reverse order.
COMBUSTION FAN
Follow the instructions above for the removal of the air/gas ratio valve.
Unplug the wiring loom connectors from the fan.
Undo the four nuts holding the fan mounting face to the underside of the burner
assembly and remove the fan.
Reassemble in reverse order.