Page 6
LAARS Heating Systems
External Set Point - Terminals
4, 5,
and
6
• The SC can accept a 4-20mA signal from an Energy Management System (EMS) or other signal
source to change the Set Point remotely (see pg. 23).
• Dip switch 6 and 8 must be
OFF
and dip switch 7 must be
OFF
OFF
ON
. These settings will allow the
ON
ON
SC to read and monitor the system water temperature using the System temperature sensor and
monitor the 4-20mA input to change the set point. (See wiring sensor on pg. 3) Also, see pg. 23 for
EMS programming parameters.
Shutdown or Setback - Terminals
7
and
77
8
• When adjusting control
SETBACK
Stb
setting to 0 the
SHUTDOWN
feature is enabled by
SHUTDOWN
SHUTDOWN
closing a dry contact and all active stages are turned off. Any pumps controlled by the SC that
were on will remain on until the System Delay is over, then they will also turn off.
• The
SHUTDOWN
feature can be used whenever it is desirable to turn off the SC from a remote
SHUTDOWN
SHUTDOWN
location or another controller (for more details see pg. 24).
• When
SETBACK
Stb
is enabled by adjusting control
SETBACK
Stb
setting to a value higher
than 0 and closing a dry contact wired to terminals 7 and 8, the SC will immediately reduce the
temperature of the circulating hot water by the
SETBACK
Stb
setting amount (see pg. 20 to
adjust the amount of
SETBACK)
. All pumps controlled by the SC that were on will remain on until the
System Delay is over, then they will turn off.
• The
SHUTDOWN/SETBACK
signal must be a dry contact only to terminals 7 and 8. No voltage can be
SHUTDOWN/SETBACK
SHUTDOWN/SETBACK
placed across the
SHUTDOWN/SETBACK
terminals.
SHUTDOWN/SETBACK
SHUTDOWN/SETBACK
Prove or Domestic Hot Water (DHW) Input - Terminals
9
and
99
10
• The Prove or Domestic Hot Water features are set by the External Input Mode in the Power Up
Sequence. It can be switched between Prove (
Pr
) and Domestic Hot Water (
dh
).
• The
PROVE
feature is used to check system components’ operation before activating any stages. See
PROVE
PROVE
pg. 24 for typical applications.
• If the
PROVE
input terminals are open, the SC will enable only the System Output relay. All Stage
PROVE
PROVE
Outputs will be off when the
PROVE
input is open.
PROVE
PROVE
• When the Domestic Hot Water (
DHW
• When the Domestic Hot Water (
• When the Domestic Hot Water (
) input is enabled by closing a dry contact, the Calculated water
DHW
DHW
temperature or the Set Point will change to 200°F and the decimal point on the left-most digit on the
display will fl ash.
• The
DHW
input will take priority over the outdoor reset function or the Outdoor Cutoff temperature.
DHW
DHW
Regardless of outdoor temperature, when the
DHW
input is closed, the SC will Sequence stages to
DHW
DHW
hold 200°F.
• If
NO
external conditions must be met before Stage Output is activated and terminals
9
and
10
are not used for Domestic Hot
Water (see pg. 25),
DO NOT
remove the factory installed jumper across the
PROVE/DHW
terminals.
PROVE/DHW
PROVE/DHW
• The
PROVE/DHW
signal must be a dry contact only to terminals 9 and 10. No voltage can be placed across the
PROVE/DHW
PROVE/DHW
PROVE/DHW
terminals.
IMPORTANT
FACTORY INSTALLED PROVE JUMPER: The
PROVE
input terminals must be
PROVE
PROVE
shorted for Stage Outputs to be activated. DO NOT remove the factory installed
PROVE jumper unless replacing it with a Prove or Domestic Hot Water signal.
Outdoor Sensor- Terminals
11
and
12
• The Outdoor Sensor must be installed if the Outdoor Reset operational mode is required (dip switch 8
ON
).
ON
ON
• Installing the Outdoor Sensor is optional in the Set Point mode (dip switch 8
OFF
). If it is installed, it will act as an Outdoor
OFF
OFF
Cutoff (see pg. 18). No stages will be activated when the outdoor temperature is above the Outdoor Cutoff.
• Locate the Outdoor sensor in the shade on the north side of the building away from doors,
windows, exhaust fans, vents, or other possible heat sources.
• The sensor should be mounted at least 4 inches away from the building wall and
approximately 10 feet above ground level.
• Sensor wires can be extended up to 500’ by splicing with 18 gauge shielded wire.
• Do not run sensor wire in conduit with line voltage.
• Temperature sensors have no polarity. Connect either wire to terminal 11 and 12.
• Connect the shield to terminal
3 SHIELD.
Note that both sensor shields will be connected
to terminal 3.
Dry Contact
Prove or Domestic
Hot Water Signal
INPUTS
5 6 7 8 9 10 11
Sensor Com
Dry Contact
Only
Dry Contact
Only
SHUTDOWN
/SETBACK
PROVE
/DHW
OUTD
4-20 ma
INPUTS
5 6 7 8 9 10 11 12
Sensor Com
Dry Contact
Only
Dry Contact
Only
SHUTDOWN
/SETBACK
PROVE
/DHW
4-20 ma
OUTDOOR
To Outdoor Sensor
In Shade
Shield
2 3 4
Com Shield
+
TEMP
4 5 6
+
Sensor Com
4-20 ma
SC Source Current
24VDC Excitation Voltage
(-) Input
(+) Signal
INPUTS
5 6 7 8 9
Sensor Com
Dry Contact
Only
Dry Contact
SHUTDOWN
/SETBACK
PROVE
4
+
4-20 ma
Dry Contact
Shutdown and
Setback Signal
4 5 6
+
Sensor Com
4-20 ma
EMS Sourcing Current
(-) Input
(+) Signal
