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20
6.21
DHW HEAT EXCHANGER fig. 16/16A
Carry out component removal procedure as
described in 6.4.
Before removing the DHW heat exchanger, it will
be necessary to remove the gas valve (see 6.13).
Locate and remove the DHW outlet pipe (A) from
the LH (left hand) DHW manifold and DHW outlet
connection.
Locate and remove the locking pins (1) that secure
the flexible pipe (B) that connects both hydraulic
manifolds and then remove the pipe.
Locate and remove the 2-screws (C) that secure
the DHW heat exchanger to the LH and RH DHW
manifolds and gently ease the DHW heat
exchanger from its location.
Locate and remove the locking pin (2) that secures
the LH DHW manifold to the LH hydraulic manifold
and then remove the manifold.
Gently ease the LH DHW manifold away from the
LH hydraulic manifold and disconnect the wiring
to the secondary (DHW) thermistor.
Replace in the reverse order ensuring all seals
are correctly positioned and in good condition.
Replace the gas valve in accordance with the
instructions detailed in 6.13.
6.22
VALVE ACTUATOR fig. 26
Carry out component removal procedure as de-
scribed in 6.4.
Remove the locking pin (A) that secures the
actuator (B) to the hydraulic manifold. Disconnect
the electrical plug from the actuator. Replace in
the reverse order.
6.23
DIVERTOR VALVE CARTRIDGE fig. 26
Carry out component removal procedure as de-
scribed in 6.4.
Remove the valve actuator as described in 6.22.
Remove the cartridge locking pin (C) and - using a
suitable pair of pliers - withdraw the cartridge
assembly. The cartridge assembly is a non-
serviceable item and therefore needs to be re-
placed if it’s suspected as being damaged or worn.
Fig. 26
Fig. 26a
Replace in the reverse order ensuring that the
seating cam inserts into the locating groove
correctly (see fig. 26a). Ensure all seals are in
good condition, taking care to ensure they are
replaced correctly.
6.24
DHW THERMISTOR fig. 27
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the electrical plug. Using a suitable
pair of pliers, remove the thermistor locking pin (E)
and ease the thermistor (F) from its seating.
Replace in the reverse order ensuring the sealing
ring is in good condition.
6.25
AUTO BY-PASS VALVE fig. 27
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the hydraulic cover locking pin
(A) and remove the cover. Using a suitable hooked
wire or screwdriver, gently ease the valve (C) from
its seating. Ensure all seals are in good condition,
taking care to ensure they are replaced correctly.
Replace in the reverse order ensuring the cartridge
is facing the correct way.
6.26
DHW NON-RETURN VALVE fig. 27
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the hydraulic cover locking pin
(A) and remove the cover. Using a suitable hooked
wire or screwdriver, gently ease the non-return
valve (D) from its seating. Ensure all seals are in
good condition, taking care to ensure they are
replaced correctly. Replace in the reverse order
ensuring the cartridge is facing the correct way.
6.27
EXPANSION VESSEL fig. 1
Should the removal and replacement of the expan-
sion vessel be deemed impractical, an external
expansion vessel may be fitted to the return pipe
as close to the appliance as possible.
6.27.1 EXPANSION VESSEL REMOVAL (with suffi-
cient clearance above)
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the flue from the appliance.
Disconnect the flexible expansion pipe from the
vessel. Locate and remove the four screws (A)
that secure the vessel top holding plate (B),
remove the plate (fig. 28). The expansion vessel
E
E
D
C
