Bosch Appliances 24i junior Setting The Gas / Air Ratio, 33.1, 33.3, B 33.4 5.5, Setting the CO2

		SETTING THE GAS / AIR RATIO
33.1
		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 P E R S O N
		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
C		EQUIPPED WITH A COMBUSTION ANALYSER
		C O N F O R M I N G TO B S 79 2 7 A N D I S
		COMPETENT IN ITS USE.
		33. Setting the CO2
	Inlet Test Nipple	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
		water through the DHW circuit to ensure that
		the boiler will not cycle on low heating demands.

33.25.1 Connect manometer to inlet pressure point

on the gas valve.

To adjust the CO2 it will be necessary to 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.

	5.2	Turn central heating control to maximum; the
		boiler will then go to maximum output.
33.3	Note: The control will resume normal operation
	after 15 minutes or if the service button is pressed
	for over a second.
	5.3	Using a flat blade screwdriver set the CO2
		via adjuster (B) using table below.

A

Please note: The flue gas test point can be accessed on the appliance flue elbow by removing cap D

D

+ –

B

33.4

5.5

–	+
C

CO2 settings

Note. CO2 should be measured after 10 minutes

Gas type	CO2 setting	CO2 setting
	maximum	minimum
Natural gas	9.8% ±0.2	9.2% ±0.2
LPG	11.0% ±0.2	10.5% ±0.2

Check CO is less than 200ppm.

Measure the inlet pressure; it should be no less than 18.5mb for natural gas and 37mb for LPG.

5.4Set the central heating control to minimum. This will make the boiler go to minimum power.

5.5Measure the CO2; it should now be at the figure for minimum output. If not adjust (C) on the gas valve until correct.

Return to maximum and re-check the CO2. 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.

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 commissioning section.

Fit new label from kit over existing label on the appliance bottom panel.

SERVICING & SPARES

52

INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR 24 i junior/28 i junior 8 716 107 336b (11/05)

REPLACEMENT OF PARTS