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OVERVIEW
The Zonex Systems TRLAT is a single stage Gas/Electric or Heat Pump
Capacity Controller. However, the heat pump feature is not compatible
with the Zonex Systems System 1000/2000 Zoning Systems so we will
only address the Gas/Electric features. If you have a heat pump that uses
heat pump controls refer to the SYCAP for System 1000 and LAS for
System 2000.
The TRLAT Capacity Controller protects both the air conditioner and
furnace. It simply measures the leaving air temperature. If the air gets
too cold (drops below the cool cutout setpoint), it breaks the “Y”
connection, disengaging the compressor, If the air gets too warm (rises
above the heat cut-out setpoint), it breaks the “W” connection, de-energizing
the furnace. To prevent short cycling, the compressor or furnace cannot
reenergize for at least four minutes after cut-out. The heating and
cooling cut-out setpoints can be changed by the installer.
OPERATION
Cool mode:
If the leaving air temperature drops below the TRLAT
cooling setpoint (field settable to 41, 44, 47 or 50 degrees Fahrenheit),
the Y (Controller) breaks from Y (Unit) and makes to G. This turns off
the compressor and keeps the indoor blower fan running to warm up
the evaporator. Four minutes after the leaving air temperature rises above
the cooling setpoint, Y (Controller) makes to Y (Unit) and breaks to G.
This restarts the compressor and returns indoor blower fan control to
the Switching Center/Controller.
Heat mode:
If the leaving air temperature rises above the TRLAT heating
setpoint (field settable to 125, 140, 150 or 160 degrees Fahrenheit), the
W (Controller) breaks from W (Unit) and makes to G. This turns off the
heater and keeps the indoor blower fan running to cool down the heater.
Four minutes after the leaving air temperature drops below the heating
setpoint, W (Controller) makes to W (Unit) and breaks to G. This restarts
the heater and returns indoor blower fan control to the heater or
Switching Center/Controller.
Cut-out disable:
The cool cutout is disabled in heat mode. The heat
cutout is disabled in cool mode. This permits the heat to turn on in a cold
building and the air conditioner to turn on in a hot building. For heat
pumps, this also prevents the compressor from cycling off when the heat
pump is in defrost mode. The O/B (Controller) input tells the TRLAT
which mode of operation (heat or cool) is active.
NOTE: For GE systems, a jumper wire (factory installed) must be
connected between O/B (Controller) and W (Controller).
COMPONENTS
A. Status Lights:
DELAY (red): On when compressor or furnace is disabled.
PWR (yellow): On when TRLAT is powered.
B. Jumpers:
GE/HP: For gas/electric systems, place jumper on GE and center
pin. For heat pumps, place jumper on HP and center pin.(Digitract
Systems only)
O/B: For heat pumps, if reversing valve is energized in cool mode,
place jumper on O and center pin. If reversing valve is energized in
heat mode, place jumper on B and center pin.
C. Unit terminal block: Connects to HVAC unit. O/B – Reversing
Valve; R – 24V AC hot; G – Blower fan; C – 24V AC rtn; W – heat; Y –
compressor. See WIRING section for detailed wiring instructions.
D. Controller terminal block: Connects to System Controller. Terminal
designations same as for Unit terminal block. See WIRING section for
detailed wiring instructions.
E. Leaving Air Sensor (LAS) Terminals: Leaving air temperature sensor
is connected to the TRLAT here. Red to + and white to –. The sensor
monitors the leaving air of the HVAC system. If preferred, the TRLAT
can be mounted up to 500 feet from the sensor. See INSTALLATION
section for further information.
F. Jumper wire: Factory installed. Must be connected between O/B
(Controller) and W (Controller) for GE systems and removed for heat
pumps.
G. Setpoint Select: Sets the heat and cool cutoff setpoints. See SETPOINT
SETUP, TRLAT section.
CAPACITY CONTROLLERS – TRLAT
GE
O
HP
B
CONTROLLER
UNIT
+ -
ON
OFF
SW1
SW2
SW3
SW4
W
Y
R
O/B
G
C
W
Y
R
O/B
G
C
D
E
L
A
Y
P
W
R
B
A
G
E
F
C
D
