Technical data

pump inlet pipe upwards 10 mm approx. and remove from the
bottom manifold. Retain the pipe, plate and screws.
To access the water to water heat exchanger the top manifold
must first be removed:
Unscrew locating screw Nos. 6, 7 and 8 in the top manifold two
full turns. Unscrew and remove screws Nos. 9 and 10 securing
the manifold to the water to water heat exchanger support
bracket. Retain the screws. See Fig. 50.
Unscrew the flat faced union securing the manifold to the inner
casing pipework. See Fig. 50.
Remove the sealing washer and discard. See Fig. 50.
Ease the manifold assembly downwards, 10 mm approx., until
clear of the heating flow and return pipes and hot water outlet
pipe. See Fig. 47.
Remove the top manifold clear of the appliance and retain.
Unscrew locating screws Nos.11 and 12 two full turns. Unscrew
and remove screws Nos.13 and 14 securing the bottom manifold
to the water to water heat exchanger support bracket. See Figs.
47 and 48. Retain the screws. Unscrew the bracket supporting
the domestic drain from the left hand side of the gas valve. Using
long nose pliers remove the clip securing the drain pipe to the
bottom manifold. Ease the drain pipe downwards out of the
manifold and remove. See Fig. 51.
Retain the clip, screw, bracket and drain pipe.
Ease the bottom manifold and water to water heat exchanger
upwards 10 mm approx. until clear of the heat bank flow and
return pipes. See Fig. 51.
NOTE: It may be necessary to push down on the flow and return
pipes to release the “O” ring fittings. Before entering the heat
bank the flow and return pipes are fitted into slip joints. The
joints are sealed with “O” rings and allow some movement
forwards or backwards when removing the bottom manifold and
water to water heat exchanger. See Fig.48.
Ease the water to water heat exchanger and bottom manifold
from the support bracket and clear of the appliance.
Release screw No.15 and remove the bottom manifold off the
locations on the water to water heat exchanger. See Figs. 50 and
48. Discard the heat exchanger. Retain the fixing screw.
IMPORTANT: Two new “O” ring seals must be fitted to the rear
of each manifold. See Fig. 52.
If the flow and return pipes to the heat bank have been disturbed
when removing the water to water heat exchanger the “O” ring
seals must be replaced :
Ease the heat bank flow pipe out of the front slip joint and return
pipe out of the rear slip joint and clear of the push in elbows. See
Fig. 51.
Remove and discard the “O” ring seals from each pipe. Replace
with new “O” ring seals.
Pull out the flat clip from the front push in elbow and remove the
elbow. Retain the clip and push in elbow. See Fig. 51.
To release the rear elbow reach under the water to water heat
exchanger bracket and push in fully the flat plate clamp
mechanism. Remove the rear push in elbow and retain. See Fig. 51.
Remove and discard the elbow “O” ring seals. Replace with new
“O” ring seals.
Re-assemble the rear and front push in elbows. Ensure the rear
clamp mechanism is engaged and fully pulled into the location.
Engage the front flat clip into the slot correctly.
Re-assemble the flow and return pipes into the slip joints. The
pipe lengths are not identical, the longest pipe is the rear/return
pipe. See Fig. 51.
Re-assemble the bottom manifold to the replacement water to
water heat exchanger. Ensure the heat exchanger is located
correctly with the internally threaded boss fitting through the
fixing hole in the manifold and the raised section on the manifold
port fitting into the bottom right hand port on the heat
exchanger. See Fig. 49. Replace screw No. 15 and tighten.
Fit the replacement water to water heat exchanger and bottom
manifold assembly into the support bracket. Ensure the heat
bank flow and return connections are fully engaged. Secure the
assembly to the support bracket with screw Nos.13 and 14. Fully
tighten the screws fixing the “O” rings Nos. 11 and 12. See Figs.
50 and 51.
Re-assemble the top manifold in the reverse order.
Ensure the heating flow and heating return and hot water pipes
are fully engaged.
Ensure a new sealing washer and ‘“O”’ ring is fitted when re-
connecting the union securing the top manifold to the inner
casing pipework. Replace the manifold top fixing screws Nos.9
and 10. Tighten screws Nos. 6, 7 and 8 and manifold union
fitting. See Fig. 50.
Re-assemble the pump outlet pipe and tighten screw No. 5. Re-fit
the pump support plate and secure with screw Nos. 3 and 4.
Ensure the flat clip is re-located.
Re-connect the open vent pipe (if applicable). Ensure a new
sealing washer is fitted.
Re-assemble the heating return pipe using the slip joint in the
bottom manifold to manoeuvre the pipe into position.
Re-assemble the cold water inlet pipe and flow switch ensure the
sealing washer is renewed. Re-connect the union fitting to the
cold water inlet valve. See Fig. 53.
Re-assemble the pressure relief valve ensure clip is replaced. See
Fig. 49.
Re-assemble the domestic drain pipe renewing the “O” seal. Re-locate
the securing clip and fixing bracket to the gas valve. See Fig. 51.
Before continuing ensure screws 1, 2, 5, 6, 7, 8, 11 and 12
are fully engaged. The “O” ring seals must be pushed fully
into the housing.
Re-assemble the water diverter valve. Re-assemble the 6 mm
diameter pressure pipe to the pump inlet pipe and diverter valve
renewing the “O” ring seals. Ensure the securing clips are
replaced.
Re-assemble the circulating pump ensure the securing clips are
re-placed.
Open the valves, fill and repressurise the system as described in
Section 12.2. Reassemble the appliance in the reverse order.
23. Water to Water Heat Exchanger Top Manifold. See Figs. 42,
46, 47, 49, 59, 51, 52 and 53.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position and lower the expansion vessel as
described in Section 14.2 a, b and c.
Drain the heating and hot water circuit as described in Section 15.2.
Refer to Section 15.3-22 and remove the Top Manifold
commencing from the instruction:
CAUTION: The weight of the water to water heat exchanger is 2
kg. approx. A quantity of water will remain in the heat exchanger
and pipework. Follow the procedure as described in 15.2.
Remove the manifold clear of the appliance Remove and retain
the brass stub connection and nut from the manifold.
Withdraw the by-pass adjuster retaining clip and unscrew the
adjuster from the manifold retaining both items.
Undo and remove the phial pocket securing clip screw and clip.
Retain both the clip and screw. Extract the phial pocket and retain.
Unscrew and retain all locating screws.
Before reassembling the appliance refit the by-pass adjuster and
phial pocket in the reverse order using new “O” rings.
Screw all locating screws fully home then unscrew each of them
two full turns. Check that none of the screws protrude into their
relevant bores.
Reassemble the manifold in the reverse order using new “O”
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