Technical information

Combi 70 & Combi 90 Oil Boilers
44
Note: If there is access to the boiler from above, e.g. it
is not fitted below a fixed worktop, use the procedure
as for the Combi 70 - See previous section 9.7. If the
boiler is below a fixed worktop and there is no access
from above, proceed as follows;
1 Shut off the cold water supply to the boiler at the
mains stopcock.
2 Drain the central heating system and boiler using
the drain cock on the boiler.
3 Slacken the four control panel fixing screws,
carefully disengage the control panel from both
casing side panels and the front top panel and
allow it to rest at an angle on its right hand end.
4 Working from the front of the boiler, disconnect
the cold water inlet pipe at both the elbow
connector in the top of the boiler, and at
connection 5 on cold water inlet isolating valve
(A), see Fig. 39.
5 Carefully manoeuvre the pipe forwards and then
down by about 100 mm to leave access to the two
compression connections on the check valve.
6 Unscrew both compression nuts on the check valve
and remove it from the boiler.
7 Unscrew and disconnect pipe union 3 from the rear
of the diverter valve. See Fig. 39. Allow the pipe to
rest on top of the plate heat exchanger.
8 Unscrew the capillary tube nut and disconnect it
from the valve.
9 Unscrew the discharge pipe compression nut and
disconnect it from the valve.
10 Unscrew the valve union and remove the valve
from the boiler.
11 Fit a replacement valve using the reverse of the
above procedure, ensuring that the sealing washer
provided is correctly fitted in the valve union
before tightening.
12 Refill the central heating system as described in
section 5.2, checking for leaks.
13 Manually operate the relief valve to check it’s
operation, then refill as above.
1 From above the boiler, remove the front top casing
panel by pulling it up on one side to disengage the
four push-in fasteners.
2 If a conventional flue is fitted to the boiler, unhook
the flexible air tube from the hook bracket on the
crossmember. Unscrew and remove the nut and
bolt fixing fastening from the centre of the
crossmember. Unscrew the four fixing screws and
remove the crossmember from the boiler.
3 Drain the central heating system and boiler using
the drain cock on the boiler.
4 Using an adjustable spanner or grips, unscrew and
remove the air vent.
5 Fit a replacement air vent using reverse of above
procedure.
6 Refill the central heating system as described in
section 5.2, checking for leaks.
Note: If there is access to the boiler from above, e.g. it
is not fitted below a fixed worktop, use the procedure
as for the Combi 70 - See previous section 9.8. If the
boiler is below a fixed worktop and there is no access
from above, proceed as follows;
1 Drain the central heating system and boiler using
the drain cock on the boiler.
2 Slacken the four control panel fixing screws,
carefully disengage the control panel from both
casing side panels and the front top panel and
allow it to rest at an angle on its right hand end, to
gain access to the Automatic air vent.
3 If a conventional flue is fitted to the boiler, unhook
the flexible air inlet tube from the hook bracket on
the crossmember, and remove the hook bracket
from the boiler crossmember.
4 Using an adjustable spanner or grips, unscrew and
remove the air vent.
5 Fit a replacement air vent using reverse of above
procedure.
6 Refill the central heating system as described in
section 5.2, checking for leaks.
9 - REPLACEMENT OF BOILER COMPONENTS
Pressure relief (safety) valve - Combi 90
9.7a
Automatic air vent - Combi 70
9.8
Automatic air vent - Combi 90
9.8a