6.3.5 Adjusting the gas valve (EX 700, EX 850)
Danger
Making adjustments to the IBC gas valve without a properly calibrated gas
combustion analyzer and by persons who are not trained and experienced in its use is
forbidden. Failure to use an analyzer can result in an immediate hazard.
To help with the following procedure, see Figure 43 .
Performing a combustion test
1.
After the boiler is lit and is at high fire, insert the combustion analyzer test probe into the
flue gas test port (see Figure 48 ). Then adjust the high fire (gas-air ratio) adjustment with
a small slot screwdriver according to Table 11 values. This adjustment screw is very
sensitive and will only need very small adjustments to fine tune the gas valve. Turn
counter-clockwise (in the direction of the '+' sign) to raise the CO2% (to richen). Turn
clockwise to lower CO2%.
2. Set the heat-out value in manual mode to the minimum MBH for the boiler (see Table 11 ).
To do this:
a. Go to Diagnostics > Test Operation.
b. Click inside the Fan Test: Heat Output box, and using the number pad, enter the
minimum MBH.
c. Select OK The fan runs to the minimum MBH you have set. Select the Fan Test:
Heat Output box to change the heat out value.
3. Low fire adjustment - adjust the low fire according to see Table 11 . Use a 2.5 mm Allen
key. Turn counter-clockwise (in the direction of the '+' sign) to raise to raise the CO
2
% (to
richen). Turn clockwise to lower CO
2
%. Start with 1/8 of a turn until you see the analyzer
measure a change then only make 1/16 adjustments. If changing direction on this
adjustment you will notice a significant backlash.
4.
Return the boiler to high fire, and check the results to confirm correct settings.
Note
Clock the gas meter to confirm full maximum rating plate input.
5. Return the boiler to low fire, and check the results to confirm correct settings.
6. To exit the Test Operation screen, select Back.
7. Turn off the gas supply at the external gas shut-off valve.
8. Remove the analyzer probe and install the test port plug.
9. Disconnect the manometer.
10. Remove the adapter fitting and reinstall the inlet test port plug, tightening with a 3mm
Section: Boiler operation
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