Buderus 800-24 Installation And Servicing Instructions page 29

Setting the gas/ratio using a pressure gauge:
Move the mains switch and chimney sweeper switch to "0".
Pull off the bottom hose attached P1 (fig. 38, item 1) and fit
a hose with Tee in between.
Connect the Tee to the negative port of the pressure
gauge.
Loosen the screw in the burner pressure measuring nipple
on Honeywell gas units (fig. 38, item 2) two turns, comple-
tely unscrew the screw on SIT gas units (fig. 39, item 1).
Connect the positive port of the pressure gauge with a
hose to the burner pressure measuring nipple
(fig. 38, item 2 or fig. 39, item 1).
Move the mains switch to "I" and the chimney sweeper
switch to "1".
When the burner has fired after approx. 30 seconds, press
the service button (fig. 37) until "Y" is shown on the display.
Move the hot water temperature controller to "1".
Read the differential pressure.
The differential pressure (p
(display on the meter: -10 to 0 Pa).
In case of gas/air ratio deviations, adjust by using the
setscrew (fig. 38, item 3 or fig. 39, item 2).
Set mains switch and chimney sweeper switch to "0".
Remove the measuring equipment, tighten up the screw in
the burner pressure measuring nipple, put the hose back
on P1.
Set the hot water temperature controller back to the original
value.
Move the mains switch to "I".
Adjustment according to the CO
The mains switch must be set to "I" and the chimney
sweeper switch to "1".
Press the service button (fig. 37) until "Y" is shown on the
display.
Full load
Move the hot water temperature controller to "10".
Measure and record the CO
measuring point (fig. 40).
Partial load
Set the hot water temperature controller to "1".
Measure and record the CO
The CO content under partial load must be 0.7 % lower
2
than the one under full load.
If the measured value is too high or too low, use the
setscrew of the gas burner unit (fig. 38, item 3 or fig. 39,
item 2) to set the gas/air ratio under partial load.
Set the hot water temperature controller to the original
value.
Set the chimney sweeper switch to "0".
Subject to modifications resulting from technical improvements !
Installation and servicing instructions condensing gas boiler 800 - 24/29/43/60 and 800 - 24T25/29T25 H/V • edition 02/2006
- p ) must be -5 Pa (±5 Pa)
Gas Air
content (natural gas):
2
content on the flue gas
2
content.
2
Initial start-up
1
2
3
fig. 38 Checking and adjusting the gas/air ratio (Honeywell gas unit)
2
1
fig. 39 Checking and adjusting the gas/air ratio (SIT gas unit)
fig. 40 Flue gas measuring point
2
Buderus • http://buderus-domestic.co.uk
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