7. Remove the manometer from the inlet gas pressure test port.
8. Tighten the inlet gas pressure test port screw.
9. Switch on the gas supply, and soap test for leaks before returning the boiler to normal
operation.
6.3.3.2 Performing a combustion test and adjustment
The High Fire (gas-air ratio) adjustment screw will have to be adjusted to attain optimum
combustion results whenever fuel conversion is undertaken, however, no mixture adjustment
must be performed unless done by a qualified technician using properly functioning and
calibrated combustion analyzing equipment.
1. Turn off the boiler’s external gas shut-off valve.
2. Give the boiler a call for heat.
3. With a small (1/8" or 3 mm) flat screwdriver, open the inlet gas supply pressure test port
by turning its center-screw one full turn counterclockwise.
4. Attach a manometer to the inlet pressure test port and turn on gas to appliance.
Static manometer reading should be ideally 7" w.c. for Natural Gas and 11" w.c.
for Propane.
Minimum and maximum static pressure should be between 4" and 14" w.c.
Monitor pressure throughout the commissioning (start-up) procedure. Pressure
may drop up to 1" to 2" w.c. at high fire.
5. To run the boiler at high fire, you can set the heat-out value in Test Operation mode to
the maximum MBH for the boiler. To do this, on the controller, go to (More) > Test
Operation > In the Fan Test: Heat Out field, tap 0 MBtu, then enter the maximum
MBH.
When the boiler reaches high fire, insert the combustion analyzer test probe into the
flue gas test port. Then verify that the CO2 reading is within the combustion test targets
at Table 12 values.
6. Adjust the high fire according to values in Table 12 using the high fire adjustment screw
. Make tiny adjustments (may require several turns). Turning the High Fire screw
clockwise will lean out the flame.
7.
Set the heat-out value in Test Operation mode to the minimum MBH for the boiler. To
do this, go to (More) > Test Operation > In the Fan Test: Heat Out field, tap 0
MBtu, then enter the minimum MBH.
8. Adjust the low fire according to values in Table 12 using the low fire adjustment screw.
Turn the screwdriver clockwise to raise the CO
2
% (to richen). Turn counter-clockwise
to lower CO
2
%. Start with ⅛ of a turn until you see the analyzer measure a change then
only make 1/16 adjustments. If changing direction on this adjustment, you may notice a
significant backlash.
Section: Boiler operation
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