IBC SL 40-399 G3 Quick Start Manual page 4

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Combustion testing and adjustment

Danger

A combustion test checks that the gas valve is operating properly in the field. To perform a combustion test, you

must be a qualified, trained and licensed gas fitter.

Making adjustments to the IBC gas valve without a properly calibrated gas combustion analyzer and by people

who are not trained and experienced in its use is forbidden. Failure to use an analyzer can result in an

immediate hazard.

Model Number

SL 40-399 G3

Table 2

Rated input of a converted boiler

Normal ignition system sequence of operation:

The boiler control, upon a call for heat or DHW, turns on the combustion fan for a 20-second pre-purge, then energizes the

spark electrode and gas valve for a 4-second trial for ignition.

If the burner does not light, the process is repeated until the burner lights and flame is detected. After 3 trials for ignition, the

boiler locks out and will need to be manually reset by clearing the error on the touchscreen controller (Diagnostics >

Advanced Diagnostics > Clear Errors). The boiler a utomatically resets after 60 minutes, if no action is taken.

To perform a combustion test and adjustment:

1. Turn off the boiler's gas shut-off valve.

2. With a small (1/8" or 3 mm) flat screwdriver, open the inlet gas supply pressure test port by turning its center-screw 1

full turn counterclockwise.

3. 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 5" 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.

4. Before you change the load to manual control, note the load setting.

5. Set the load to manual control, and set the heat-out value to the maximum MBH for the boiler. This load should be

large enough to allow the boiler to operate at high fire for over 10 minutes.

6. With a combustion analyzer probe in the flue gas test port, check the flue gas reading and adjust the gas:air ratio

screw to bring the flue gas to within the parameters indicated in Table 1

7. Adjust slowly (clockwise) the High Fire (Gas : Air Ratio Adjustment) screw to obtain the correct CO

Table 1

4 |

High Fire Input

399 MBH

value (see