8
RT-SVX51L-EN
Economizer Control Actuator
Electromechanical Control
The ECA monitors the mixed air temperature, return air
temperature, minimum position setpoint (local or remote),
power exhaust setpoint, CO
2
setpoint, CO
2
, and ambient
dry bulb/ enthalpy sensor or comparative humidity (return
air humidity against ambient humidity) sensors, if selected,
to control dampers to an accuracy of ±5 percent of stroke.
The actuator is spring returned to the closed position any
time that power is lost to the unit. It is capable of delivering
up to 25 in
﹒
lb of torque and is powered by 24 Vac.
JADE Economizer Control - Low Leak
Economizer (LLE) Only
The JADE controller is a standalone economizer controller
that provides outdoor air dry-bulb economizer control
standard. With optional Sylk Bus sensors, the controller
can provide comparative or reference enthalpy control.
Dampers are controlled to an accuracy of ±3.2 percent of
stroke. The actuator is spring returned to the closed
position any time that power is lost to the actuator. It is
capable of delivering up to 88 in
﹒
lb of torque and is powered
by 24 Vac.
System Input Devices and Functions
The unit must have a thermostat input in order to operate.
For units with Low Leak Economizer (LLE), the thermostat
must be a smart thermostat as listed by the CEC (a list of
thermostats can be found at
title24/equipment_cert/ocst/index.html
The descriptions of the following basic input devices used
within the unit are to acquaint the operator with their
function as they interface with the various features. Refer to
the unit’s electrical schematic for the specific device
connections. The following controls are available from the
factory for field installation.
Drain Pan Condensate Overflow Switch
(Optional)
This input incorporates the Condensate Overflow Switch
(COF) mounted on the drain pan. When the condensate
level reaches the trip point, the COF relay energizes and
opens the 24 Vac control circuit, disabling the unit. A delay
timer prevents the unit from starting for 3 minutes.
Phase Monitor
The Phase Monitor is a three-phase line monitor module
that protects against phase loss, phase reversal and phase
unbalance. It is intended to protect compressors from
reverse rotation. It has an operating input voltage range of
180–600 Vac, and LED indicators for ON and FAULT.
There are no field adjustments and the module will
automatically reset from a fault condition.
Discharge Line Thermostat Control
The high pressure controls and the discharge line
thermostat signals are wired in series and connected to the
safety input of the LSD. The compressor contactor coil is
connected to the ‘CC’ terminal of the LSD. If the high
pressure control switch or the discharge line thermostat is
open, the 24 Vac signal to the SI input of the LSD is
interrupted and the compressor contactor coil supply is
disabled by the LSD. It has an automatic lockout.
Power Exhaust Control (Optional)
The power exhaust fan is started whenever the position of
the economizer dampers meets or exceed the power
exhaust setpoint when the indoor fan is on.
The setpoint panel is located in the return air section and is
factory set at 25% (50% for LLE).
To configure the LLE controller, set EXH1 SET (or EXH1 L
& EXH1 H with two-speed fan) in the SETPOINTS menu.
2-speed fan mode requires AUX2 I set as W.
Evaporator Frost Control
This input incorporates the Frostat™ control (FOS)
mounted in the indoor coil and can be activated by closing
a field supplied contact installed in parallel with the FOS.
If this circuit is open before the compressor is started, the
compressor will not be allowed to operate. Anytime this
circuit is opened for 5 continuous seconds during
compressor operation, the compressor for that circuit is
immediately turned “Off”. The compressor will not be
allowed to restart for a minimum of 3 minutes should the
FOS close.
Locking Safety Device with Anti-Short Cycle
Timer
This device monitors compressor safety switch trips to
prevent short cycling, protecting the compressor. A manual
reset is required after a fourth safety switch trip.
Sensors
High Temperature Sensor (BAYFRST003*)
This sensor connects to the Emergency Stop Input on the
LTB and provides high limit “shutdown” of the unit. The
sensor is used to detect high temperatures due to fire in the
air conditioning or ventilation ducts. The sensor is designed
to mount directly to the sheet metal duct. Each kit contains
two sensors. The return air duct sensor (X1310004001) is
set to open at 135°F.
The supply air duct sensor (X1310004002) is set to open at
240°F. The control can be reset after the temperature has
been lowered approximately 25°F below the cutout
setpoint.
Thermostat (TCONT802AS32DA)
This thermostat is a multi-stage 3 heat/2 cool,
autochangeover digital display thermostat. It is a
programmable thermostat, and a 7-day programmable stat
with night setback shall be available. In addition, it is wall
mounted.
