22
Fig. 27
Fig. 28
Fig. 29
A
B
C
D
E
F
I
J
Fig. 30
Fig. 31
M
N
I2
J2
G
H
Fig. 32
O
P
K
L
via the drain valve. Ensure some water absorbent cloths are
available to catch any residual water that may drip from the
appliance or removed component. Undertake a complete com-
missioning check as detailed in section 5, after replacing any
component.
ALWAYS TEST FOR GAS TIGHTNESS IF ANY
GAS CARRYING COMPONENTS HAVE BEEN
REMOVED
OR DISTURBED.
6.4.1 AIR BOX FRONT COVER REMOVAL (ig. 27)
Locate the 4 screws and remove air box front cover.
6.5 PUMP ASSEMBLY (ig. 28)
Carry out component removal procedure as described in 6.4.
Disconnect and remove the pump outlet pipe (
A
) from the pump
assembly/combustion chamber connection.
Remove the expansion pipe locking pin (
B
) from the top of the
pump assembly and withdraw the lexible pipe. Locate and
remove the pressure gauge securing pin (
C
) and disconnect
the pressure gauge from the pump assembly. Disconnect the
electrical wiring from the pump’s electrical connection point (
D
).
Locate and remove the 2 securing screws (
E
) at the rear of the
pump assembly. Remove locking pin (
F
) from pump base and
lift pump assembly clear of the hydraulic manifold. The pump
assembly can now be removed from the appliance. Replace
carefully in the reverse order.
6.6 SAFETY VALVE (ig. 29)
Carry out component removal procedure as described in 6.4.
Disconnect the outlet pipe (
G
) from the safety valve, remove
safety valve locking pin (
H
) from the hydraulic manifold. Replace
in the reverse order.
6.7 LOWER AUTOMATIC AIR RELEASE VALVE
(ig. 28)
Carry out component removal procedure as described in 6.4.
Remove the expansion pipe locking pin (
B
) from the pump as-
sembly and remove the expansion pipe. Locate and remove
the AAV locking pin (
I
) from the pump assembly and remove
the AAV assembly (
J
). Replace in the reverse order.
6.7.1 TOP AUTOMATIC AIR RELEASE VALVE (ig. 30)
Carry out component removal procedure as described in 6.4.
Unclip and remove the air chamber front cover. Remove the
AAV locking pin (K) from the deaerator assembly and remove
the AAV assembly (L). Replace in the reverse order.
6.8 WATER PRESSURE SWITCH (ig. 31)
Carry out component removal procedure as described in 6.4.
Locate and remove the locking pin (
M
) from the water pressure
switch (
N
). Remove the wiring. Carefully withdraw the switch.
Replace in the reverse order.
6.9 FLOW THERMISTOR (ig. 4 - pos. 17)
Carry out component removal procedure as described in 6.4.
Unclip and remove the air chamber front cover. Unclip the low
thermistor from the low outlet pipe. Disconnect thermistor
electrical plug. Replace in the reverse order.
6.10 RETURN THERMISTOR (ig. 4 - pos. 20)
Carry out component removal procedure as described in 6.4.
Unclip the return thermistor from the return inlet pipe. Discon-
nect thermistor electrical plug. Replace in the reverse order.
6.11 PRINTED CIRCUIT BOARD (ig. 32)
Carry out component removal procedure as described in 6.4.
Pull the control fascia forward and lower it. Push the clips (
O
)
which secure the PCB cover, remove cover, after carefully tak-
ing note of all wiring connections and jumper tag coniguration.
Unhook and remove connection block (
P
). Disconnect all wiring
