Sime FORMAT 34E BF, Manual

Page: 23 / 32

21
Before commencing any service operation, ISOLATE the
mains electrical supply, and TURN OFF the gas supply at the
main service cock. It is the law that any service work must be
carried out by registered personnel.
8.1 HEAT EXCHANGER
– Remove the fan as described in section 8.3.
– Disconnect the pressure sensing pipe from the flue box,
lift the collector hood assembly, tilt forwards, and remove
the hood.
– Isolate the boiler from the system.
– Drain the heat exchanger using the drain cock (at the bot-
tom RHS of the appliance)
– Unclip the heat exchanger securing clips and unscrew
completely the expansion vessel nut.
– Disconnect the pipes from the exchanger and lift out the
heat exchanger.
– Re-assemble in reverse order, ensuring that the heat
exchanger seals and clips are correctly located and that
the pressure sensing pipe is correctly re-fitted. The fan
polarity is not important except the earth conductor (G/Y
which is marked on the appliance).
– Refill, and re-commission the system as described in sec-
tion 4.
8.2 COMBUSTION CHAMBER INSULATION
The design of this appliance is such that the rear and side
insulation should not require replacement unless mechanical-
ly damaged.
IMPORTANT: When handling insulation panels, take care to
avoid producing or inhaling dust particles. When removing
old or damaged insulation panels, dampen with water to
minimise dust.
To replace the insulation front panel, proceed as follows:
– r e m o v e t h e c o m b u s t i o n c h a m b e r f r o n t p a n e l a s
described in section 5.1;
– replace the front insulation panel and glue it into position
on the front panel using the glue supplied. Re-assemble in
reverse order.
Should the rear or side panels become damaged, replace
them as follows.
– remove the heat exchanger as described in section 8.1;
– remove the side insulation panels followed by the rear
panel;
– re-assemble in reverse order, refill, and recommission the
system as described in section 4.
8.3 FAN ASSEMBLY
– Remove the casing front panel and sealed chamber front
panel as described in section 5.1.
– Disconnect the electrical connections and the pressure
sensing pipes to the fan. Note the position of the earth
conductor.
– Unscrew the three screws securing the fan.
– Drop and tilt the fan forwards and remove in a down-
wards direction.
– Re-assemble in reverse order. Ensure that the earth con-
nection is correctly refitted. Note that the polarity (Line
and Neutral) is immaterial.
8.4 MAIN BURNER
– Remove the main burner by following section 5.1.
– Transfer the ignition electrode onto the new burner
assembly.
– Re-assemble in reverse order. Check the electrode gaps
(fig. 23) and test for gas soundness.
– Re-commission the appliance as described in section 4.
8.5 IGNITION/DETECTION ELECTRODE (Fig. 22)
– Remove the casing front panel and sealed chamber front
panel as described in section 5.1.
– Unscrew the single screw securing the electrode in posi-
tion, and release the electrode from the burner.
– Remove the electrode and disconnect its cable from the
ignition transformer.
– Replace the electrode and re-assemble in reverse order.
8.6 GAS VALVE
– Remove the casing front panel as described in section 5.1.
– Disconnect the two leads from the modulating solenoid
and disconnect the valve connector (one screw).
– Unscrew the nut between the inlet pipe and the valve.
– Unscrew the burner manifold nut underneath the
sealed chamber, and withdraw the gas valve complete
with outlet pipe.
– Transfer the outlet pipe onto the new gas valve, using a
new gasket (supplied with the valve).
– Fit the new gas valve assembly into the appliance using
the other new gasket supplied on the valve inlet, and re-
assemble in reverse order.
– Re-light the appliance, check for gas soundness, and re-
commission in accordance with section 4.
In addition it will be necessary to set the D.H.W. and C.H.
heat inputs, with reference to fig. 23, as follows:
Note that it is necessary to set the MAXIMUM PRESSURE FIRST.
– Connect a pressure gauge to the burner pressure
test point.
– Remove the sealing cap of the proportioning unit (C) by
rotating it ⁄ turn anticlockwise.
– Adjust DHW potentiometer to maximum, then fully open
any DHW tap to light the boiler.
– Using a 10 mm spanner, turn nut (B) to attain the maxi-
8 REPLACEMENT OF PARTS
Fig. 22
4
± 0.5
IGNITION/DETECTION
ELECTRODE