Air Pressure Switch; Clip In Modules; Display Screen; Low Gas Pressure Switch - Hamworthy Wessex Modumax 100 series Installation, Comissioning And Servicing Instructions

If a 'Clip in Module 'is fitted, this must first be removed.
Carefully disconnect the
module to the LMU - terminal X50, X40. Depress the
locking latch at the connector end of the clip in to allow
the module to be hinged up and disengaged from the
LMU.
Unplug the electrical connections to the PCB noting the
orientation and relative positions. Remove the 4 M5
nuts securing the controller to the control panel and
withdraw.
Fit the replacement PCB in reverse order as described
above. Remember to apply the parameters local to the
installation on initialisation - refer to section 8 - Controls
Operation. Re-light the boiler and check for correct
operation.

11.10 Clip in Modules

Part No. 533901438 - vfc relay output, 0~10v
AGU2.511A109
Part No. 533901456 - lpb communication
OCI420A109
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Carefully disconnect the
module to the LMU - terminal X50, X40.
Carefully disconnect the plug from the top of the clip in
module.
Depress the locking latch at the connector end of the
clip in to allow the module to be hinged up and
disengaged from the LMU.
Assemble in reverse order.

11.11 Display screen

Part Number 533901437
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Carefully disconnect the ribbon cable connecting the
screen to the LMU control, terminal X30. Remove the 4
screws securing the screen panel to the controls pod.
Remove the 4 nuts securing the screen to the front
panel of the controls fascia and remove the display pcb.
Remove the ribbon cable plug from the pcb and replace
the display in reverse order.

11.12 Low Gas Pressure Switch

Part Number 533901420
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
HAMWORTHY HEATING LTD
plug securing the clip in
plug securing the clip in
WESSEX MODUMAX 100 SERIES
Isolate the boiler module gas supply by closing the gas
service valve.
Remove the screw securing the cover to the low gas
pressure switch,
connections, noting the position.
Unscrew the low gas pressure switch from the gas inlet
pipe and replace in reverse order, checking gas joints for
soundness.
Set to correct pressure.

11.13 Air Pressure Switch

Part Number 533901318
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Disconnect the sensing tube from the switch noting the
position. Remove the 2 screws securing the cover to the
switch and disconnect the electrical connections noting
their position. Remove the 4 screws securing the
pressure switch body to the control bracket and remove
the switch.
Fit the replacement unit in reverse order. Set to correct
pressure.
39
and disconnect the
500001123/C
electrical