Modulex EXT Commercial Series Boilers User Manual
CHAPTER 4: Installation Instructions
OMM-0095_0H
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
67
of
144
GF-139
Phone: 800-526-0288
09/15/2017
4.33.3 Minimum Output Calibration
After setting the maximum gas output for each valve (section 4.33.2), refer to Figure 4-28,
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 4.34
(Figure 4-30) ‘’Sweeper’’ function (CASCADE MAN 10%).
2. Check that the CO
2
values are within the values indicated in Table 4-6, below.
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 the CO
2
percentage is too low, check if the air and exhaust flue are obstructed. If they are not
obstructed, check if the burner and/or the exchanger (aluminum sections) are properly cleaned.
After confirmation, check the maximum gas settings again (in section 4.33.2).
4.33.4 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:
Ignition Failure Adjustment Procedure
Figure 4-29: Maximum Output Adjustment Screw
1. Tighten the maximum adjustment screw “A” (see Figure 4-29) in a clockwise direction until it is
fully abutted into the gas valve body, than 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, than 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,
described in section 4.33.2 and 4.33.3, above.
