Flue Gas Analysis; Setting The Air/Gas Ratio; Setting The Co/Co2 - Worcester GREENSTAR 24i Junior Installation, Commissioning And Servicing Instructions

Fig. 80 Sump access
6.5

FLUE GAS ANALYSIS

Ensure that the gas inlet pressure is correct before
continuing, refer to section 5.5.1
COMBUSTION TEST:
▶ Connect the flue gas analyser to the flue gas sampling point as shown
in the figure below.
▶ Run the boiler at maximum output for at least 10 minutes.
▶ Check the CO/CO readings against the information in table 18 CO/
2
CO settings on page 38.
2
Fig. 81 Combustion test
If the boiler fails the combustion test, check:
1. Air intake for restriction
2. Diaphragm in the fan, for correct operation
3. Cleanliness of the heat cell, plus blockages in the condensate
disposal.
6 720 802 047 (2013/05)
3.
2.
1.
1.
6720643895-112.1Wo
6.6

SETTING THE AIR/GAS RATIO

NOTICE: 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 TEST IS EQUIPPED
WITH A COMBUSTION ANALYSER CONFORMING TO BS
7927 AND IS COMPETENT IN ITS USE.
6.6.1 SETTING THE CO/CO
2
When running in the service mode, the boiler will operate
both the central heating and 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.
▶ Refer to section 5.5.1 and ensure that the gas inlet pressure is
correct before continuing.
▶ To adjust the CO/CO it will be necessary to first operate the boiler at
2
maximum output.
1. Press and hold down the service button for more than 10 seconds
until illuminated.
The blue power indicator will flash.
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 service button is pressed for over a
second.
1.
3.
2.
Fig. 82 Setting the boiler
▶ Refer to table 18 and check the CO/CO
the maximum CO/CO via adjuster (1) on the gas valve using a 2.5mm
2
Allen key.
▶ Check CO is less than 200ppm.
3. Set the central heating control to minimum.
▶ The boiler will go to minimum power.
▶ Measure the CO/CO and check against the table 18 below.
2
If required set the minimum CO/CO
until the correct measurement is set:
– Remove dust cap with flat bladed screw driver.
– Using a 4mm Allen key adjust CO
– Replace dust cap.
▶ Check that the CO is less than 200ppm.
▶ Return to maximum and re-check the CO/CO
If correct, press the service button;
the button will cease to be illuminated and the blue power indicator
will be permanently illuminated.
▶ Re-assemble and refit boiler case.
SERVICE AND SPARES
at maximum. If required set
2
via adjuster (2) on the gas valve
2
2
.
2
37