Technical information

Combi 70 & Combi 90 Oil Boilers
36
6 - COMMISSIONING
11 a Having ensured that there are no oil leaks, replace
the burner cover. Tighten the two fixing screws.
Ensure the flexible air tube is connected to the
burner.
b Replace the plinth (if it was removed). Locate
the left hand side over the locating stud and
locate the slot in the right hand side over the
screw previously loosened. Tighten the fixing
screw.
12 Relight the boiler and allow it to run for 20 minutes
then check the following:-
CO
2
level, Flue gas temperature and Smoke
Number. Refer to the Technical Information in
sections 2.2 and 2.3.
A flue gas sampling test point is provided.
Combi 70 - In the cleaning cover on top of the
boiler.
Combi 90 - In the cleaning door on the front of the
boiler.
A flame viewing point is provided, just above the
burner (see Fig. 32). Use this to view the flame not
as a test point.
13 Check the smoke number, if satisfactory check the
CO
2
. Adjust the burner air regulator, see Fig. 31.
Turning the screw anti-clockwise closes the
damper and increases CO
2
level, turning the screw
clockwise opens the damper and reduces CO
2
level.
Re-check the smoke number if the air damper has
been moved.
Under no circumstances must the smoke number be
above 1.
A suitable position for the air damper is one which
gives 1% less CO
2
than that which has a smoke
number of 1.
Note: It is important that the air damper is
correctly set.
14 Check the flue gas temperature.
15 Check the boiler overheat thermostat by removing
the boiler thermostat phial (the shorter one) from
the pocket in the front of the boiler, just to the left
above the pump. The boiler should switch off on
the overheat thermostat and the red neon light.
Replace the phial. Unscrew and remove the plastic
cap covering the reset button, press the reset button
and replace the cap.
16 When the boiler has been adjusted and is running
satisfactorily, balance the central heating system by
adjusting the radiator lock shield valves. Start with
the radiator nearest the boiler and adjust the valves
to achieve the required temperature drop across
each radiator.
If thermostatic radiator valves have been installed,
check the system by-pass.
17 Switch off the boiler.
18 With the system hot, check again for leaks,
rectifying where necessary. Drain the heating
system while it is hot to complete the flushing
process.
19 Refill, vent and pressurise the system as described
in section 5.2, adding a suitable inhibitor. For
further information concerning inhibitors contact
Grant Engineering (UK) Limited.
20 Replace the case bracing bracket and top panel, if
they are not already fitted.
Note: After commissioning the boiler you should
complete the Commissioning Report on page 2 of
these instructions.
If the boiler is to be left in service with the User, set
the controls, timer (see section 1) and room thermostat
(if fitted) to the User's requirements then refer to
section 7.
If the boiler is not to be handed over immediately,
close the boiler fuel supply valve and switch off the
electricity supply.
If there is any possibility of the boiler being left during
frost conditions, then the boiler and system should be
drained.
Set the thermostatic blending valve to provide a hot
water temperature at the outlets between 45 and 50°C.
21 Replace the pipework cover.