To Check The Diaphragm In Burner Cover; To Clean The Condensate Trap; Setting The Air/Gas Ratio - Worcester 29CDi GC 47-406-34 Installation, Commissioning And Servicing Instructions

SERVICING AND SPARES
3. Remove the burner (H) and clean components.
Do not use a wire brush.
E E
3.

6.1.5 TO CHECK THE DIAPHRAGM IN BURNER COVER

4. Carefully withdraw diaphragm (J) from fan intake tube and check for
soiling and splits.
B Carefully refit diaphragm (J) the correct way round into the fan intake
tube, the diaphragm flaps must open upwards.
B Re-assemble burner in reverse order using a new seal (K).
B Adjust gas/air ratio. Refer to section "Setting the gas/air ratio".
4.
I I

6.1.6 TO CLEAN THE CONDENSATE TRAP

1. Pull condensate pipe out of the adaptor.
2. Remove trap from boiler.
B Clean trap and check that the heat exchanger connection is clear.
B Fill the condensate trap with approximately 1/4 litre of water and refit
in reverse order.
38
G
H
J
K
6.2

SETTING THE AIR/GAS RATIO

NOTICE: Air/Gas ratio
B The setting of the gas ratio must be carried out by a
competent person.
Setting the air/gas ratio must not be attempted unless
the person carrying out the operation is equipped
with a combustion analyser conforming to BS 7927
and is competent in its use.
SETTING THE CO
2
When running in the Performance test mode, the boiler
will operate only the central heating circuit.
To avoid the boiler cycling on low heating demands,
remove the diverter valve motor from the valve body and
run the domestic hot water tap throughout the
Performance test mode.
Refit the diverter valve motor once all the tests are
completed, page 44
1. Connect manometer to inlet test point on the gas valve.
B To adjust the CO it will be necessary to first operate the boiler at
2
maximum output.
B Press and hold down the Performance test mode button for 10
seconds until illuminated.
2. Turn central heating control to maximum; the boiler will then go to
maximum output.
The control will resume normal operation after 15
minutes or if the Performance test mode button is
pressed for over a second.
3. Using a flat blade screwdriver set the CO
referring to the table below.
CO2 should be measured 10 minutes after firing the
appliance.
Gas type CO setting maximum CO
2
Greenstar 29 and 34CDi
Natural gas 9.6% ±0.2
LPG 11.5% ±0.2
Greenstar 38 and 42CDi
Natural gas 9.7% ±0.2
LPG 11.5% ±0.2
Table 10
B Check CO is less than 200 ppm.
B Measure the gas inlet pressure at the gas valve test point; it should be
no more than 2.5mbar less than the pressure at the meter for natural
gas and no more than 4mbar less than the pressure at the regulator for
LPG.
4. Set the central heating control to minimum. This will make the boiler
go to minimum power.
5. Measure the CO ; it should now be at the figure for minimum output.
2
B If not, use a 4mm Allen key to adjust the min adjustment on the gas
valve until correct.
B Return to maximum and re-check the CO
B If correct press and hold down the Performance test mode button for
two seconds; the button will cease to be illuminated.
B Remove manometer and re-seal inlet pressure point on gas valve.
via the max adjuster
2
setting minimum
2
9.0% ±0.2
10.5% ±0.2
9.1% ±0.2
10.5% ±0.2
.
2
6 720 803 599 (2012/06)