
Supplied By www.heating spares.co Tel. 0161 620 6677
37
221473B
Diagram 4.9
SECURING
SCREW (2)
SAFETY
VALVE
SEALING
WASHER
PRESSURE
GAUGE
CONNECTION
PRESSURE
GAUGE
PRESSURE
GAUGE
BRACKET
2831
Diagram 4.8
ELECTRICAL
CONNECTORS
D.H.W.
HIGH
LIMIT
CONTROL
SECURING
SCREW (2)
DHW HIGH LIMIT CONTROL
6626
Diagram 4.7
WATER
PRESSURE
SWITCH
4814
4 Replacement of Parts
4.9 Water Pressure Switch
Release the water pressure and drain the central heating circuit
of the boiler, refer to Section 1.3 and 1.6.
Remove the control housing as Section 4.11.
Disconnect the electrical connectors at the pressure microswitch,
see diagram 4.7.
Remove pressure switch, see diagram 4.7.
Replace the “O” ring seal with the new seal provided.
Make sure that the switch terminals are facing diagonally
forwards to give access, as shown in diagram 4.7.
Reconnect the electrical connections, refer to diagram 4.12.
4.10 Domestic Hot Water High Limit Control
Remove the pump, see Section 4.24.
Disconnect the electrical connectors at the domestic hot water
high limit control, see diagram 4.8.
Remove the high limit control from the flow pipe, secured with
two screws.
Use the heat sink compound supplied, between the mounting
plate and the control.
When refitting the electrical connections to the high limit control
the polarity is not important, see diagram 4.12.
4.11 Pressure Gauge
Remove the control housing assembly, secured with two screws.
Support the control housing on a surface or by screwing it to the
front edge of the base, using one of the screws previously
removed, see diagram 4.10.
Release the water pressure and drain the central heating circuit
of the boiler, refer to Section 1.3 and 1.6.
Remove the pressure gauge bracket.
Disconnect the pressure gauge connection from the safety
valve, discard the washer, see diagram 4.9.
Remove the pressure gauge secured with the retaining spring
tabs.
Locate the supplied washer under the pressure gauge
connection when refitted to the safety valve.
4.12 Control Boards
If applicable, remove the clock/timer mounting bracket securing
screws, see diagram 4.27.
Remove control housing cover, temperature control knob and
the fascia, see diagram 4.10.
Remove the control housing assembly, see Section 4.11.
Disconnect all multi-pin connectors, see diagram 4.11.
Remove the control boards from the support posts, noting their
correct positions. Great care must be taken when handling any
control board.
THE MAIN CONTROL BOARD MUST BE KEPT IN THE ANTI
STATIC HOLDER UNTIL IMMEDIATE REQUIREMENT.
To connect the multi-pin connectors correctly, see diagram
4.11.
When replacing the main control board check and if necessary
adjust the main burner gas pressure in both the hot water and
central heating modes. Refer to “Commissioning” in the
Installation Instructions.