LAARS IGI-180C-5(N,X) - Service Manual - Manual (Page 13)

II - SPECIFICATIONS (cont.)
DIP SWITCH SETTINGS
Combustion Blower Dip Switch Settings for Vent Length Compensation Under 22 Feet (6.7 m):
To assure optimum efficiency and reduced noise levels, the combustion blower switch has two dip switch
settings. Dip switch number 1 (top dip switch) is shipped from the factory set to the OFF position to
compensate for the maximum vent/air intake length.
Depending upon the vent/air intake length of the installation, Dip Switch Number 1 may need to be adjusted
to compensate for the venting system distance.
When the Total Equivalent Length of vent pipe is more than 22 feet (6.7 m), leave the Dip Switch Number 1 in
the OFF position. This is the factory Dip Switch setting.
When the Total Equivalent Length of vent pipe is 22 feet (6.7 m) or less, Dip Switch Number 1
must be moved to the ON position.
Dip Switch #1 is located in the top row of dip switches, 1 through 8 on the PC board. See the following
diagram to identify the correct switch. If you do not understand the information concerning the Dip Switch
settings or the location of the Dip Switch, contact LAARS® Heating System for assistance. Use the following
examples and the previous discussion on calculating the equivalent vent length to determine the correct
setting for Dip Switch #1.
Example #1: Dip Switch Settings (Fig. 8)
You have 6 feet (1.82 m) of vent pipe and two 90˚ elbows.
D = 6 + (2 x 6) + (0 x 1.5)
D = 18 feet (5.49 m) of equivalent vent pipe
Dip Switch #1 should be moved to ON position.
Example #2:
You have 15 feet (4.57 m) of vent pipe, one 90˚ elbow, and two 45˚ elbows.
D = 15 + (1 x 6) + (2 x 1.5)
D = 24 feet (7.3 m) of equivalent vent pipe
Leave Dip Switch #1 in the OFF position (factory setting).
WARNING
Do not alter Dip Switch #1 before using the formula and venting charts to determine the equivalent vent
length. All other dip switches with the exception of Dip Switch #1 shown in the illustration MUST NOT be
altered. Unauthorized adjustments can cause property damage, personal injury, scalding, or death.
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