Excel HE C24 User Manual page 48

76 HEAT ENGINE REPLACEMENT
1. Refer to Frame 51.
2. Remove the boiler front, side and sealing panels.
Refer to Frame 44 and 45.
3. Drain the boiler water circuits. Refer to Frame 67.
4. Remove the inner sealing panel.
5. Remove overheat thermostat clip from heat
exchanger right hand side.
6. Pull off heat exchanger LH side retention clip and
pull pipe downwards to disengage copper pipe
'O' ring seal.
7. Pull off recuperator LH side pipe connection
retention clip and pull pipe downwards to
disengage 'O' ring seal.
8. Disconnect recuperator plastic drain connection
from recuperator RH side.
9. Unscrew the union connection on the recuperator
RH side brass outlet connection and swivel the
brass piece to clear the copper pipe.
10. The heat exchanger can now be pulled forward to
remove (flex the collector hood sides to clear the
heat exchanger and flex the pipe connections to
facilitate removal).
11. Fit the new heat exchanger and re-connect all
water pipe and drain connections.
Note. Ensure the recuperator RH side brass
connection and its copper pipe are correctly
aligned before tightening the union nut.
77 EXPANSION VESSEL REPLACEMENT
If the expansion vessel is faulty, there are two
options:
A. If it has a punctured diaphragm but is
otherwise leak free then it can be left in place
and a new vessel added to the return side of
the CH system, external to the boiler
providing it is of adequate capacity and pre-
charge pressure.
B. The boiler can be removed from the wall and
the expansion vessel replaced:
1. Refer to Frame 51.
2. Drain the boiler water circuits. Refer to
Frame 67.
3. Unscrew all of the gas water and condensate
connection unions.
4. Remove the flue turret.
5. Remove the front and side panels. Refer to
Frame 44 and 45.
6. Lift the complete boiler from the wall
mounting plate and place on a flat surface,
face down to expose the expansion vessel.
7. Unscrew the expansion vessel flexible hose
from the copper pipe.
8. Remove the top support bracket.
9. Lift the expansion vessel from its side
retaining brackets.
excel HE -
Installation and Servicing
SERVICING
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12. Re-connect the overheat thermostat clip to the heat exchanger pipe.
UNDER NO CIRCUMSTANCES REFIT THE OVERHEAT THERMOSTAT
ONTO THE COLD RECUPERATOR RETURN PIPE.
13. Re-assemble in reverse order.
14. Re-fill the boiler. Refer to Frame 32.
15. Check the operation of the boiler. Refer to Frame 50 and 51.
10. Fit the new expansion vessel.
11. Re hang boiler on wall bracket and reconnect all water, gas
and flue connections.
12. Re-assemble in reverse order.
13. Refill the boiler. Refer to Frame 32.
14. Check the operation of the boiler. Refer to Frame 50 and 51.
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