Slant/Fin VSL-160C Part B - Manual (Page 30)

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Figure 12-4 Combustion air pressure probes
Figure 12-5 Differential pressure gauge
connections to checking the combustion air
pressure
12.8 - Check the
combustion air pressure
The boiler has a factory-set air/gas ratio. The pressure
of the gas at the burner is indirectly controlled by the
blower. The combustion air pressure must be checked
as follows while refering to Figures 12-4 and 12-5:
1. use a differential manometer with a precision of at
least 0.1 in.W.C. (0.25 mbar);
2. close the manual gas shut off valve, Figure 11-1;
4. open the boiler casing following Section 14.2;
5. remove plug “B”;
6. turn pressure probe screw “C” one turn
counterclockwise;
7. insert tube “F”, from the negative side of the
manometer, through the opening of plug “B”, and
connect it to pressure probe “C” as shown in Figure
12-5;
8. remove plug “A” from the pressure probe and
connect the differential positive side of the
manometer to it;
9. the manometer connections must be made as shown
in Figure 12-5, to get the correct pressure reading;
10. replace panel “H” of Figure 14-1 and latch it closed.
If panel “H” is not properly in place the manometer
reading will not be accurate;
11. turn the power switch to on, item “12” in Figure 13-1;
12. press the and keys together for more
than 10 seconds, until a blinking is displayed;
13. the combustion blower will run at maximum speed
for 10 minutes. During this time the burner will not
light;
14. compare the pressure on the manometer with the
table in Section 15, raw “Combustion air pressure”.
15. if the combustion air pressure is too low, check that
there are no obstructions in the combustion air and
vent systems and check that the fl ue and air intake
length meet with the rules of Section 10.4.;
16. if the combustion air pressure is within tolerance
press the button to return the boiler to its
normal running mode;
17. once the combustion air pressure check has
been performed, disconnect the manometer, close
pressure probe screw “C”, re-install everything like
on Figure 12-4. Close the boiler casing and turn the
manual gas shut off valve on.
12 - START-UP