SERVICE AND SPARES
6 720 804 532 (2012/09)
35
Fig. 74 Set boiler to maximum
FAN PRESSURE
Fig. 75 Fan pressure test point
▶ Remove the cover and connect a digital manometer to the fan
pressure test point.
▶ After measurement replace test point cover.
▶ The pressure will read negative, refer to the chart in figure 76.
Fig. 76 Fan pressure readings
If the boiler fails the fan pressure test then before adjusting the air/gas
ratio, try the following:
▶ Check the syphon is not blocked.
1. Remove the screws securing the sump cover.
2. Remove the sump cover.
3. Clean the sump and heat exchanger with a suitable brush
▶ Check the exhaust path and flue for restriction.
▶ Re-check the Fan Pressure readings
Fig. 77 Sump access
6.5
FLUE GAS ANALYSIS
COMBUSTION TEST:
▶ Connect the flue gas analyser to the flue gas sampling point as shown
in the figure below.
▶ Run the boiler at maximum output for at least 10 minutes.
▶ Check the CO/CO
2
readings against the information in table 20 CO/
CO
2
settings.
Fig. 78 Combustion test
If the boiler fails the combustion test, check:
1. Air intake for restriction
2. Diaphragm in the fan, for correct operation
3. Cleanliness of the heat cell, plus blockages in the condensate disposal
NOTICE:
The boiler must be run at maximum output for Fan
Pressure test and the Flue Gas analysis.
1.
2.
6720643895-106.1W
o
6720804530-13.1W
o
6720644743-32.1W
o
NG Boilers
0
-6
-5
-4
-3
-2
-1
-8
-7
mbar
LPG Boilers
0
-6
-5
-4
-3
-2
-1
-8
-7
mbar
FAN PRESSURE TEST
Clean the Heat Ex.
Heat Ex. ok
- 8.0
- 4.1
18 i System:
24 i System:
12 i System:
15 i System:
- 3.9
- 5.8
- 7.4
- 3.1
18 i System:
24 i System:
12 i System:
15 i System:
- 3.6
- 5.5
1.
1.
2.
3.
6720804530-14.1W
o