Setting The Gas/Air Ratio - Bosch Worcester GREENSTAR CDi Series Instruction Manual

THE SETTING OF THE GAS RATIO MUST BE CARRIED OUT BY A COMPETENT PERSON
SETTING OF THE GAS RATIO MUST NOT BE ATTEMPTED UNLESS THE PERSON CARRYING OUT
THE CONVERSION IS EQUIPPED WITH A COMBUSTION ANALYSER CONFORMING TO BS 7927
AND IS COMPETENT IN ITS USE
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~ O R C E S T E R
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER BOSCH GREENSTAR 25CDV30CDV37CDci42CD•
6 720 613 700a (2006/11)
Bosch Group
SETTING THE GAS/AIR RATIO
5. Setting the C0
2
Note: When running in the central heating
boost mode, the boiler will operate both the
central heating & DHW circuits. This is to allow
sufficient time for the setting procedure. It will
be necessary to run water through the DHW
circuit to ensure that the boiler will not cycle on
low heating demands.
5.1
~
Connect manometer to inlet pressure
point on the gas valve.
~
To adjust the C02 it will be necessary to
first operate the boiler at maximum output.
~
Press and hold down the central heating
boost button (A) for 10 seconds until illumi-
nated.
5 . 2 ~
Turn central heating control to maximum;
the boiler will then go to maximum output.
Note: The control will resume normal opera-
tion after 15 minutes or if the central heating
boost button is pressed for over a second.
5 . 3 ~ Using a flat blade screwdriver set the
C02 via adjuster (B) using table below.
Note: C02 should be measured
10
minutes
after firing the appliance.
Gas type
I
co
2 . setting
I
C ? ~
setting
max1mum m1mmum
Greenstar 25CDi and 30CDi
Natural gas
I
9.6%
±0.2 1
9.0%
±0.2
LPG
I
11.5%
±0.2 1
10.5%
±0.2
Greenstar 37CDi and 42CDi
Natural gas
I
9.7%
±0.2 1
9.1%
±0.2
LPG
I
11.5%
±0.2 1
10.5%
±0.2
~
Check CO is less than 200 ppm.
~ M e a s u r e
the inlet pressure; it should be a
minimum of 18 mbar for natural gas and
37 mbar for LPG.
5 . 4 ~ Set the central heating control to mini-
mum. This will make the boiler go to mini-
mum power.
5 . 5 ~
Measure the C02; it should now be at
figure for minimum output. If not adjust (C)
on the gas valve until correct.
~ Return to maximum and re-check the
C02. If correct press and hold down the
central heating boost button for 2 seconds;
the button will cease to be illuminated and
the blue power indicator will be permanently
illuminated.
~
Remove manometer and re-seal inlet pres-
sure point on gas valve.
~ Fit new plastic sealing cover on to outlet
adjuster (B).
~
Fit white cover over valve adjuster (C) and
secure with black security tag.
~ Remove red arrow from data plate and fit
new one in correct position for gas type.
~ Re-assemble and refit boiler case.
~
Re-connect mains electrical supply and
check boiler operation as stated in the com-
missioning section.
~
Fit new label from kit over existing label on
the appliance bottom panel.
SETTING THE GAS/AIR RATIO