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