LAARS SC 12 - Install and Operating Manual - Manual (Page 8)

Page 8 LAARS Heating Systems
POWER UP SEQUENCES
• Whenever the SC is powered up, it displays the software version number and then the
operating parameters. Each display will remain on the screen approximately 5 seconds. If
the parameters are correct, there is no need to make any adjustments.
• Once the parameters have been set for a particular application, they will be retained in memory and will not need to be reset.
• Note that if you do change any parameter, or make any changes to the dip switch positions, all
settings will revert to their default values and must be reset.
• A parameter can only be changed in the start-up Sequence. To restart, it is necessary to remove and
reapply power.
• Set the parameters to fi nd the appropriate Sequence for your application, Set Point Control -
Temperature and External Set Point (pgs. 10 and 11) or Outdoor Reset (pgs. 12 and 13)
Set Point Control - Temperature and External Set Point
Temperature Display Mode Default: Fahrenheit
• The SC can be fi eld adjusted to read temperature sensors and display the Set Point either in °F or °C.
• The sensor input range is from -35 to 250°F or from -30° to 120°C.
• If the display shows °F the SC will operate in Fahrenheit. If the display shows °F °F °C then the SC will operate in Celsius. °C °C
• To change the temperature display mode, hold down the center button while pushing either the UP button to increase the value, UP UP
or the DOWN button to decrease the value. DOWN DOWN
• When the correct display mode is shown, release the button and wait approximately 5 seconds. If any changes were made, the
display will fl ash.
Set Input Terminals 9 and 10 to PROVE or DHW Default: Prove Pr
• If the system is designed to provide heat and DHW, the SC can be programmed to hold a 200°F Setpoint when a call for DHW is
connected to Input terminals 9 and 10 (see pg. 25).
• All other applications should use the default Prove setting (see pg. 24).
• If the display shows Pr the Input terminals 9 and 10 will function in the Prove mode. If the display shows dh then the same
terminals will function in the DHW mode.
• To change the Input terminal functions, hold down the center button while pushing either the UP button to increase the value, or UP UP
the DOWN button to decrease the value. DOWN DOWN
• When the correct value is shown, release the button and wait approximately 5 seconds. If any changes were made, the display
will fl ash.
Set the Sequencing Mode Default: Normal
• For most applications, the Normal or PID type Sequencing mode provides the most stable operation. Stages are turned on or off Normal Normal
based on the rate of change of the system temperature and the impact a stage has on that rate.
• For applications where the stages are oversized for most load conditions, the SC has an Oversize System (OSS) Sequencing
mode that brings on stages proportionally, based on how high above or far below the Set Point the current system temperature is.
For more details, see pg. 21.
• If the display shows nor (Normal) then the SC will Sequence in the PID type mode. If the display shows OSS then SC will
Sequence stages based on a Throttling Range thr around the Set Point SP.
• To change the Sequence function, hold down the center button while pushing either the UP button to increase the value, or the UP UP
DOWN button to decrease the value. DOWN DOWN
• When the correct value is shown, release the button and wait approximately 5 seconds. If any changes were made, the display
will fl ash. This completes the startup Sequence and the SC will display the sensor temperature.
Outdoor Reset Control
Temperature Display Mode Default: Fahrenheit
• The SC can be fi eld adjusted to read temperature sensors and display the Set Point either in °F or °C.
• The sensor input range is from -35 to 250°F or from -30 to 120°C.
• If the display shows °F the SC will operate in Fahrenheit. If the display shows °F °F °C then the SC will operate in Celsius. °C °C
• To change the temperature display mode, hold down the center button while pushing either the UP button to increase the value, UP UP
or the DOWN button to decrease the value. DOWN DOWN
• When the correct display mode is shown, release the button and wait approximately 5 seconds. If any changes were made, the
display will fl ash.
Minimum Water Temperature Default: 140°F
• T
for the appropriate setting or call Laars for information.
INCREMENT
AUTO
OFF
LEAD STAGE
ROTATION
For Automatic Lead
Stage Rotation
Output
OFF
AUTO
ON
For Non-Active
Stages
For Stages Which are
to be Part of the
Automatic Sequence