Checking And Adjusting The Gas-To-Air Ratio - Buderus 24C Servicing Manual

3 Troubleshooting

3.1.28 Checking and adjusting the gas-to-air ratio

Set mains switch (fig. 82, item 1) and chimney-sweep
switch (fig. 82, item 3) to "0".
Unscrew the sealing closure of the burner-pressure testing
nipple by one turn (fig. 81).
Set pressure gauge to zero.
Connect the positive terminal of the pressure gauge with
a hose to the burner pressure measuring nipple (fig. 81).
NOTE
The negative terminal of the pressure gauge
MUST NOT be connected.
Turn the mains power switch to "I" and the chimney-sweep
switch to "1".
When the burner has fired (after approx. 30 seconds), push
the service button (fig. 82, item 2) and keep it pressed until
"Y" is shown on the display.
Set the heating-capacity controller (fig. 82, item 4) to "1".
Read the differential pressure. The differential pressure
(p – p ) must be -5 Pa (±5 Pa) (display on meter: -
gas air
10 PA to 0 PA).
In the event of any anomaly in the gas-to-air ratio, readjust
at the setscrew (fig. 81, item 1).
NOTE
Remove the cover fixing screw before
readjusting. The cover fixing screw must be
secured before readings can be taken.
Turn mains power switch and chimney-sweep switch to "0".
Remove the measuring equipment and retighten the screw
in the burner-pressure measuring nipple.
Readjust the heating capacity controller to its original
(factory default) setting.
Turn the mains power switch to "I".
Subject to modifications resulting from technical improvements!
62 Servicing manual for wall-mounted condensing gas boiler 600 Series 11S/19S/24S/24C • Issued 02/2006
Fig. 81 Check the gas-air ratio
1
Fig. 82 Check the default gas-air ratio settings
Buderus Ltd. • http://www.buderus-domestic.co.uk
1
2
11
KW
0 1
1 2
10
1
10
1
10
3
4