Worcester GREENSTAR 25Si Instruction Manual page 56

THIS PAGE SHOWS THE SETTING PROCEDURE FOR THE DUNGS
VALVE FOR ALTERNATIVE VALVE SEE PAGE 54.
A
Please note: The flue gas test point can be
accessed on the appliance flue elbow by
removing cap D
D
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR 25Si/30Si
8 716 115 165a (06/2008)
30.1
C
Inlet Test Nipple
30.2
30.3
B
30.4
30.5
C
SETTING THE AIR / GAS RATIO
FOR DUNGS GB-ND 055 DO1 S20
THE SETTING OF THE GAS RATIO MUST BE
CARRIED OUT BY A COMPETENT PERSON.
SETTING OF THE GAS RATIO MUST NOT BE
AT T E M P T E D U N L E S S T H E
C A R R Y I N G O U T T H E C O N V E R S I O N I S
EQUIPPED WITH A COMBUSTION ANALYSER
C O N F O R M I N G TO B S 79 2 7
COMPETENT IN ITS USE.
30. Setting the CO/CO
2
NOTE: When running in the service 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 sufficient
water through the DHW circuit to ensure
that the boiler will not cycle on low
heating demands.
30.1 Connect manometer to inlet pressure point
on the gas valve.
To adjust the CO/CO it will be necessary to
2
first operate the boiler at maximum output.
Press and hold down the service button (A) for
10 seconds until illuminated. The blue power
indicator will flash.
30.2 Turn central heating control to maximum; the
boiler will then go to maximum output.
NOTE: The control will resume normal operation
after 15 minutes or if the service button is
pressed for over a second.
30.3 Using a 2mm hexagonal ball driver set the
CO via adjuster (B) using table below.
2
CO/CO settings for Greenstar Si
2
. Measure CO/CO after 10 minutes
N
OTE
2
Gas type
CO setting CO
2
maximum minimum
9.8% ± 0.5%
Natural gas 9.2% ± 0.5%
11.0% ± 0.5%
LPG
10.5% ± 0.5%
CO - less than 200ppm (0.002 ratio)
Check CO is less than 200ppm.
Measure the inlet pressure; it should be no
less than18.5mb NG or 37mb for LPG.
30.4 Set the central heating control to
minimum. The boiler will go to minimum
power.
30.5 Measure the CO/CO and check against the
2
table above. If required adjust (C) on the gas
valve, using a 2mm hexagonal ball driver, until
the correct measurement is set.
Check that the CO is less than 200ppm.
Return to maximum and re-check the CO/CO
If correct press and hold down the service 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 pressure
point on gas valve.
Re-assemble and refit boiler case.
REPLACEMENT OF PARTS
P E R S O N
A N D I S
setting
2
.
2
55