INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR Ri
8 716 115 168a (06/2008)
39
THIS PAGE SHOWS THE SETTING
PROCEDURE FOR THE SIT 848.093
SIGMA VALVE.
FOR ALTERNATIVE DUNGS VALVE REFER
TO PAGE 40 .
1. Setting the CO/CO
2
1.1
Remove 3 screws (A) and cover (B) from
control box.
1.2
Clipped inside the cover is a plastic tool, using
this tool change the mode switch to maximum.
Ensure the boiler is powered up and
there is a demand from the external
controls.
The power indicator will flash and the boiler
will stay in this mode for 15 minutes if no
further change is made to the switch.
1.3
After running the boiler for 10 minutes
connect a manometer to the inlet pressure
point on the gas valve, compare the CO/CO
2
measurement with the table below.
1.4
Using a 2.5mm allen key set the CO/CO
2
via
adjuster (C) using the table below.
Check CO is less than 200ppm.
Measure the inlet pressure; it should be no
less than 18.5mb for NG or 37mb for LPG.
1.5
Set the mode switch to minimum.
1.6
Measure the CO/CO
2
and check against the
table
above. If required adjust (D) on the gas valve
until the correct measurement is set. Remove
brass dust cap with flat bladed screwdriver.
Then using a 4mm allen key adjust CO/CO
2
.
Replace dust cap.
Check CO is less than 200ppm.
Return to maximum and re-check the CO /
CO
2
. If correct set the mode switch to normal
and isolate mains supply.
Remove manometer and re-seal inlet pressure
point on gas valve.
Re-assemble and refit boiler case.
Gas type
CO/CO
2
settings for Greenstar Ri
N
OTE
.
CO/CO
2
should be measured
after 10 minutes
Natural gas
LPG
9.8% ± 0.5%
11.0% ± 0.5%
9.2% ± 0.5%
10.5% ± 0.5%
CO
2
setting
maximum
CO
2
setting
minimum
THE SETTING OF THE GAS RATIO MUST BE
CARRIED OUT BY A COMPETENT PERSON.
SETTING OF THE GAS RATIO MUST NOT BE
ATTE M PTE D U N LESS TH E PE R SON
CAR RYI NG OUT TH E CONVE R SION IS
EQU I PPE D WITH A COM B USTION
ANALYSER CONFORMING TO BS 7927
AND IS COMPETENT IN ITS USE.
Please note:
The flue gas test point can be
accessed on the appliance flue elbow by
removing cap E
E
1.5
MAX
NORM
MIN
A
B
Min
‘D’
Inlet test
nipple
Max
‘C’
1.6
Min
‘D’
+
I
1.4
1.1
Max
‘C’
+
i
MAX
NORM
MIN
1.2
1.3
SETTING THE AIR / GAS RATIO
FOR THE SIT 848.093 SIGMA
CO - less than 200ppm (0.002 ratio)
SETTING THE AIR/GAS RATIO
FOR THE SIT 848.093 SIGMA
SER
V
IC
IN
G
& S
P
AR
E
S
