Modulex Light Commercial Series
CHAPTER 4: Installation Instructions
OMM-0158_A
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Minimum Output Calibration
After setting the maximum gas output for each valve (section 4.34.2), refer to Figure 4-38,
above, to locate the Minimum Gas Adjustment screw (B) on each valve. Follow the instructions
below to set the minimum gas output level for each valve.
Adjusting the Minimum (B) Gas Output Setting:
1. Operate the burner to a minimum power following the procedure described in section 4.35
“Service Mode” function (MANUAL BOILER FIRING RATE REQUEST: 10%).
2. Check that the CO
2
values are within the values indicated in Table 4-6.
3.
If necessary, correct the value by turning the adjustment screw “B” in a CLOCKWISE direction
to increase the value or ANTICLOCKWISE to decrease it the value.
4. Repeat the adjustment for all gas valves in the boiler.
NOTE:
If CO
2
percentage is too low check air and exhaust flue for obstruction. If not obstructed,
check if the burner and/or the exchanger (aluminum sections) are properly cleaned. After
confirmation, check the maximum gas settings again, as described in section 4.34.2, above.
Final Check and Ignition Failure Adjustment Procedure
After completing the Minimum and Maximum output adjustments, check the CO
2
minimum and
maximum values at the flue outlet and, if necessary, make any required adjustments.
If the boiler fails to ignite, perform the following procedure:
Figure 4-35: Maximum Output Adjustment Screw
1.
Tighten the maximum adjustment screw “A” in a clockwise direction until it is fully abutted into
the gas valve body, then slacken back out for nine (9) turns.
2. Verify boiler ignition.
3. If the boiler goes into lockout,
slacken the screw “A” again for one turn, then retry ignition.
4. If the boiler goes into lockout again, repeat step 3 and retry ignition.
5. Once ignition succeeds, carry out the minimum and maximum gas output burner adjustments
as previously described in sections 4.34.2 and 4.34.3, above.
