Startup
40
RT-SVX34F-EN
LCI - LonTalk® Communication Interface
(Optional)
This module is used when the application calls for a
LonTalk building management type control system. It
allows the control and monitoring of the system through
a Trane Tracer Summit panel or 3rd party LonTalk system.
The module can be ordered from the factory or ordered as
a kit to be field installed. Follow the installation
instructions that ship with each kit when field installation
is necessary.
BCI - BACnet® Communication Interface
(Optional)
This module is used when the application calls for a
BACnet building management type control system. It
allows the control and monitoring of the system through
a Trane Tracer SC panel or 3rd party BACnet system. The
module can be ordered from the factory or ordered as a kit
to be field installed. Follow the installations instructions
that ship with each kit when field installation is necessary.
Manual Motor Protectors (380V Through
575V Only)
Manual motor protectors will be used as branch circuit
protection for compressors and supply fan motors. These
devices are capable of providing both overload and short-
circuit protection.
Before operating, the manual motor protector must be
switched with the rotary on/off switch to the “ON” position
and the overload setpoint dial must be set to the
appropriate rating of the motor.
Important:
In order to avoid nuisance trips, the
overload setpoint dial must be adjusted to
the following calculated value: Overload
Setting = (Motor FLA) x 1.12
Overload Setting = (Compressor RLA) x 1.12
System Operation
Economizer Operation with a
Conventional Thermostat (CV Only)
If the ambient conditions are suitable for economizer
operation, the economizer is activated as the 1st step of
cooling from Y1. The dampers are controlled to provide a
supply air temperature of 50° F +/- 5° F. If the economizer
is disabled due to ambient conditions, the 1st stage of
mechanical cooling is activated.
While economizing, if an additional stage of cooling is
activated from Y2, the 1st stage of mechanical cooling is
activated. If the economizer is disabled due to ambient
conditions, the 2nd stage of mechanical cooling is
activated.
The supply fan is activated from the G terminal and will
cycle with a call for heat or cooling if in the “Auto” mode.
It will run continuously in the “On” mode regardless of any
other system demand.
On gas heat units, first and second stages are activated by
the W1 and W2 terminals on the CTI. On electric heat units,
only two stages of heat are available. If the W2 terminal is
activated without activating the W1 terminal, the RTRM
will bring on both stages of electric heat.
The Conventional Thermostat connections can also be
utilized as a generic building automation system interface
for constant volume ICS applications. Due to the limited
heating and cooling steps when using a conventional
thermostat, compressor staging will vary on units with
three compressors.
Note:
If a conventional thermostat is used with a unit that
has modulating gas heat, the unit will control to the
Discharge Air SP potentiometer on the RTOM when
heating with a W1 call only. The unit will go to high
fire with W1 + W2.
Microelectronic Control Features
1.
Anti short cycle timer (ASCT) function. Compressor
operation is programmed for 3 minutes of minimum
“ON” time, and 3 minutes of minimum “OFF” time.
Enhances compressor reliability, and ensures proper
oil return.
Note:
Compressor cycle rate minimization, extends
compressor life expectancy. Minimizes damaging
compressor inrush current, and guards against
short cycling.
2. Delay between stages timer function. When combined
with a standard Zone Sensor Module, the Reliatel
Refrigeration Module (RTRM) provides a 10 second
minimum “ON” delay for compressor staging.
3. Built in Fan Delay Relay function for Constant Volume
and Single Zone VAV units. When the fan mode switch
on the Zone Sensor Module is set in the auto position,
the RTRM provides individual supply fan timing
Figure 38.
Manual motor protectors
