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