Lead Color
Function
Troubleshooting
Red
35 VDC Positive power terminal
Fan will only operate at max speed if disconnected
Blue
35 VDC Negative power terminal Fan will only operate at max speed if disconnected
Black
Signal from controller
Fan will only operate at max speed if disconnected
White
Fan tach.
2 pulses/rev (freq x3 0=rpm)
8.1.3 Water pressure sensor
The water pressure sensor ensures that there is adequate pressure in the heating system for safe
operation. The pressure is displayed in PSI as the default. If the system pressure should drop below
8PSI the firing rate of the boiler is reduced. If the pressure drops to 4PSI or lower, the boiler will not
fire.
Check the operation of the sensor by isolating the boiler from its system piping, and close the system
fill valve, and then crack the pressure relief valve. The pressure displayed should reflect declining
pressure. If it remains “fixed”, drain the boiler and replace the sensor, or dislodge any blocking debris
from the sensor inlet channel and reinsert.
8.1.4 Safety and Ignition Module (SIM)
The SIM is a safety control, certified to conform to the UL 60730-5-5 and ANSI Z21.20 • CAN/CSA-
C22.2 No. 60730-2-5-14 standards.
The module controls the boiler’s combustion fan, gas valve, sensors, safety and ignition functions
including, and provides:
Direct spark ignition
Flame detection and current measurement
Flue gas temperature sensing
Supply water maximum temperature shutdown
Flue gas maximum temperature shutdown
Low water cut-off.
95
8.1.3 Water pressure sensor
Summary of Contents for SL Series
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Page 12: ...Figure 5 Top view SL 40 399 G3 Figure 6 Bottom view SL 40 399 G3 8 Section Specifications...
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Page 64: ...Figure 40 Electric wiring connections 60 Section Installation...
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Page 110: ...Internal wiring diagram Figure 46 Internal wiring diagram 106 Section Appendices...
Page 111: ...Sequence of operations Figure 47 Sequence of Operation 107 Sequence of operations...