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17
6.7
SAFETY VALVE fig. 16
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect and remove the safety valve outlet
pipe. Locate and remove the safety valve securing
pin (B). The safety valve can now be removed.
Replace in the reverse order.
Check and clean (if necessary) the condense trap
(see 6.29).
6.8
WATER PRESSURE SWITCH fig. 1
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the 2-wires from the water pressure
switch, taking note of their locations. Locate and
remove the pin that secures the water pressure
switch to the hydraulic assembly. Remove the
water pressure switch from the hydraulic assembly.
Replace in the reverse order.
6.9
PRESSURE/TEMPERATURE GAUGE fig. 1
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the pressure gauge securing
pin and disconnect the pressure gauge from the
pump assembly. Locate the spring tabs on the
pressure gauge body, push and hold tabs in, to
enable extraction of the gauge from its location on
the control panel.
Replace in the reverse order.
6.10
PRIMARY THERMISTOR fig. 17
Carry out component removal procedure as de-
scribed in 6.4.
Unclip and remove the air chamber cover and
remove the right side air baffle.
Disconnect thermistor electrical plug.
Using a 13mm spanner slacken and remove the
thermistor and sealing washer (1,2) from the main
heat exchanger.
NB, it may be necessary to disconnect or remove
the flow pipe from the heat exchanger to facilitate
this.
Replace in the reverse order.
6.11
HIGH LIMIT THERMOSTAT fig. 18
Carry out component removal procedure as de-
scribed in 6.4.
Unclip and remove the air chamber cover.
Pull off electrical connections from the high limit
thermostat (2), slacken and remove retaining
screws (3).
Replace in reverse order.
6.12
PRINTED CIRCUIT BOARD fig. 19
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the screws that secure the
PCB cover, then remove cover. After carefully
taking note of all wiring connections, disconnect
all wiring from the PCB, locate and remove the
PCB securing screws (2,3,), remove the required
PCB (Main or ignition control). Replace in the
reverse order.
NOTE
Ensure that any replacement PCB has the correct
jumper tag configuration, and that the relevant gas
pressures are correctly set/adjusted (see 7.8.1).
6.13
GAS VALVE fig. 20
Carry out component removal procedure as de-
scribed in 6.4. The gas valve must be changed as
complete unit. Disconnect the electrical plug and
leads from the gas valve.
Slacken and unscrew gas valve inlet and outlet
connections (3). Please note, the sealing wash-
ers (2) must be discarded and replaced with new
sealing washers (2). Locate and remove gas valve
retaining screws on the underside of the boiler if
required. The gas valve can now be removed.
Replace in the reverse order. Check and adjust
burner pressure settings. WARNING, A GAS
SOUNDNESS CHECK MUST BE CARRIED OUT.
Fig. 18
Fig. 17
Fig. 16
E
B