Microelectronic Control; Features; Controls - Trane Voyager Commercial Installation, Operation And Maintenance Manual

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.
N N o o t t e e : : 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
Anti Short Cycle Timer (ASCT)
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.
N N o o t t e e : : Compressor cycle rate minimization, extends
compressor life expectancy, minimizes
damaging compressor inrush current, and
guards against short cycling.
Delay Between Stages Timer
When combined with a standard Zone Sensor Module,
the Reliatel Refrigeration Module (RTRM) provides a 10
second minimum "ON" delay for compressor staging.
Built-in Fan Delay Relay (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 sequences for each system
in heating and cooling. The RTRM provides different
timing sequences for Gas Heat units and Cooling only
units.
Low Ambient Cooling
Low ambient cooling to 0°F with Frostat™.
Built-in Electric Heat Staging
Provides a 10 second "ON" delay between resistance
heat stages.
Economizer Preferred Cooling
Allows fully integrated economizer operation with
mechanical cooling if actually needed.
RT-SVX34R-EN
On Constant Volume and Single Zone VAV
applications, a 3 minute delay allows the RTRM to
evaluate the rate of change in the zone. If the zone
temperature is dropping faster than acceptable
parameters, the compressor(s) will not be required to
operate.
Free Night Setback
Allows the unit to enter an unoccupied mode by simply
shorting across terminals RTRM J6-11 and J6-12. The
short can be achieved by a set of dry contacts or a time
clock. Once this short has been made the unit will close
the economizer dampers, go from continuous fan to
auto fan operation.
ON CV or SZ VAV units with mechanical ZSM:
• If the unit has a valid cooling and heating setpoint,
the setup/setback is a minimum of 7°F.
• If the unit does not have both setpoints, the setup/
setback is 0°.
• If the unit has neither setpoint, the unoccupied
cooling/heating setpoints will be 74°F/71°F.
• If the unit is configured as a Constant Volume unit
and a conventional thermostat is used, this input is
ignored and the unit will respond to thermostat
requests as during normal occupied mode.
• VAV unit w/o ICS or NSB energizes heating if the
space temperature drops to 10°F below the MWU
setpoint but not less than 50°F.
• This option can not be used with programmable
ZSM or with an ICSTM system.
Low Pressure Cutouts
Low pressure cutouts on all compressors have been
added to insure compressor reliability in low
refrigerant flow situations. The compressor(s) will
lockout after four consecutive low pressure control
trips during the compressor minimum 3 minute "on"
time. The lockout will have to be manual reset as
explained in this document.
Economizer Operation with CV Controls
The control point for the economizer is designed to
control at least 1.5°F below the cooling setpoint or 1.5°
F above the heating setpoint, whichever produces the
highest economizer control setpoint.
Example:
Heating Setpoint = 68°F
Cooling Setpoint = 70°F
The control temperature for the economizer will be 1.5°
F above the heating setpoint due to it producing the
least amount of offset.
Heating Setpoint = 55°F
Cooling Setpoint = 75°F
S S t t a a r r t t u u p p
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