Specifications

Thermostat
•CoolingSetPoint:65°Fthrough95°F(18°Cthrough
35°C) in 1° increments.
•HeatingSetPoint:50°Fthrough80°F(10°C
through 27°C) in 1° increments.
Differential
•AllstagesONdifferential:2°Fthrough5°F(1°
through 3°C) in 1° increments.
•AllstagesOFFdifferential:1°Fthrough5°F(1°
through 3°C) in 1° increments. The 2nd stage
differential is referenced to the 1st stage differential
and the outputs will stage off as each stage’s
differential is satisfied.
•ChangeoverDifferentialbetweencoolingand
heating:Minimumof3°F(2°C).
•3rdstageheatingDifferential:0°Fthrough7°F(0°C
through 4°C) in 1° increments
Control Voltage
•TheCommStat4ispoweredbyanominal24VAC
or with a user provided 24 VDC or 48 VDC power
supply. Should AC power be lost, the display, user
interface and the alarm outputs remain functional.
Systemoutputs(Y,G,W,OandtheMixedAir
Relay) will not be functional when 24 VAC is not
present. If the control voltage is not present, the
Low Voltage Loss alarm relay is energized.
Operating Range: -40°Fthrough150°F(-40°C
through66°C)
Minimum Voltage: 18 VAC
Maximum Voltage: 30 VAC
Ease of Installation
•Wiringconnectioninsensitivetophasingofthe
units.
•Easyterminalconnectionsforthermostatwire.
•Remotetemperaturesensorsinsureaccurate
temperature readings in the shelter.
•Easyattachmenttothewall.
Lead/Lag Operation
•
User selectable changeover from ½ to 7 days in ½
day increments. If the lead unit loses power, the lag
unit automatically becomes the lead unit with all
the set points of the lead unit. A lead swap button
alternates the lead and lag unit, allowing service
techs to easily check the operation of each unit.
Alarms
Dry contacts can be used for remote alarm or noti-
fication.RelayscanbewiredNormallyOpen(NO)
orNormallyClosed(NC).Mostalarmrelayscanbe
resetbyturningtheCommStat4OFFandthenON
ORtheUPandDOWNbuttonsareheldsimultane-
ously for 4 seconds. Alarms can be reset provided
there is no longer an input from the smoke detector
.
All alarms are functional when 24 VAC is applied to
the board. If 24 VAC is not present, no alarms will be
displayed unless DC power is present. If DC power is
supplied to the board, the display is operational.
• High(Line)Voltage-activatediflinevoltageisnot
present. The CommStat 4 requires a line voltage
of 230VAC input from each air conditioner or heat
pump to monitor for the presence of line voltage.
If line voltage is not present, the High Voltage Loss
alarm relay is energized. If desired, this alarm can
be disabled by the user in Configuration Set up.
•Low(Control)Voltage–activatedifcontrolvoltage
is not present.
•Lockout–activatedifanyairconditionerorheat
pump is off due to either high or low refrigerant
pressure lockout. If all the air conditioners or heat
pumpsarelockedout,theMixedAirRelay(MAR)
will be activated on each of the air conditioners or
heat pumps. This air conditioner or heat pump will
go into the Ventilation mode, provided there is a
call for cooling. If desired, the lockout alarm can
be disabled by the user in the Configuration Set-up.
•LowBuildingTemperatureAlarm–Activatedifthe
temperature in the building drops to the selected
temperature. If the low building temperature
alarm is activated, the LCD displays, “Low Building
Temperature”
.
•FirstStageHighBuildingTemperatureWarning–If
the set point temperature is reached, the display
will show, “First Stage High Building Temperature”
on the LCD display.
• Second Stage High Building Temperature Alarm-
If the set point temperature is reached, the
display will show, “Second Stage High Building
Temperature” on the LCD display and all outputs
areturnedoffwiththeexceptionoftheMixed
AirRelay(MAR)andtheAirMoverRelay(AMR).
Iftheairconditioner(s)orheatpump(s)onthe
shelterhaveeconomizer(s),theeconomizer(s)will
open,andtheindoorblower(s)willbeenergized
(EmergencyVentilationMode).
•
SmokeAlarm–thecontactswillbeenergized
when the smoke detector inputs receive a signal
fromanexternaldetector.Allairconditionersor
heat pumps are immediately shut down. A physical
reset is required to clear the alarm in the manual
mode. If auto reset has been selected, the alarm
willresetaftertheuserspecifiedtime(3-10
minutes).
•AUX1andAUX2–Twoauxiliarydrycontactoutputs
thatcanbeenergizedbaseduponAUX1andAUX2
inputs.
Specification/Features
CommStat 4 PDS 8.2011 rev 4 2
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