LAARS SC 12 - Install and Operating Manual - Manual (Page 5)

Page 5 Laars Sequencing Controls
INSTALLATION
MOUNTING THE SC
• Select a location near the equipment to be controlled.
• The surface should be fl at, and be suffi ciently wide and strong to hold the SC.
• Keep the control away from extreme heat or cold. Ambient operating
temperature is from 20 to 120°F.
• Remove the panel from the metal enclosure by removing the top center screw
and loosening the two screws at the bottom of the panel. Lift the panel out.
• Screw the enclosure to the surface through the mounting holes in the back of
the enclosure.
• Be sure to set the dip switches before returning the panel to the enclosure.
SET THE DIP SWITCHES
• The dip switch chart is shown on page 4.
• The dip switch is located on the back on the SC board (the side of the board without
the metal front panel).
• The dip switch sets all of the following:
- System relay output type - Combustion Air Damper, or System Pump operation
- Stage type - On/Off, Lo/Hi, 3 Stage or 4 Stage
- Rotation Sequence - First On/Last Off or First On/First Off
- Input type - Temperature or External Set Point
- Operation - Set Point or Outdoor Reset
IMPORTANT
The dip switches must be set correctly. Carefully, check the details of the installation and
determine the appropriate dip switch settings before continuing on to the next steps.
WIRING THE POWER INPUTS
• Bring the 120VAC 60Hz power wires through a bottom knock out of the enclosure.
Class 1 voltages must enter the enclosure through a different opening from any Class 2
voltage wiring.
• Connect the hot line to terminal marked LINE.
• Connect the neutral line to the terminal marked NEUT.
• The green ground screw must be connected to earth ground.
• Wiring a surge suppressor is recommended before wiring to the SC Control.
WIRING THE INPUT TERMINALS
System Temperature Sensor - Terminals 1, 2, and 3
• The System Temperature Sensor must be installed for the control to operate correctly.
• The SC is designed to be connected to standard brass tube sensor (Laars Part # CA002400).
Contact the factory for additional temperature sensor options.
• Sensor must inserted in a 3/8” well (Laars Part # CA002500).
• Locate the sensor where it will register the water temperature output of all the stages. Sensor
should NOT be installed in between boiler connections to header. If the sensor does not
register the output of all the stages, it will not be able to Sequence properly.
• Temperature sensor wires can be extended up to 500’ by splicing with 18 gauge shielded wire.
• Do not run wire in conduit with line voltage.
• Temperature sensors have no polarity. Connect either wire from the sensor to terminal 1 SENSOR.
• Connect the other sensor wire to terminal 2 COM. 2 COM 2 COM
• Connect the shield to terminal 3 SHIELD.
NOTICE
If the dip switch is changed
during operation, the SC will be
completely reset. Wait until the
SC restarts and then reprogram
all settings.
Mounting Holes
LINE
NEUT Surge
Suppressor
Power Switch
Ground
Line
Neut
INPUTS
1 2 3 4 5 6
Sensor Com Shield + Sensor Com
TEMP PRES 4-20 ma
Shield
To Temperature Sensor
in Common Header