Trane PKG-PRC002-EN Generic Building Automation System Module Gbas Option, Gbas Analog Inputs

Sequence of

Controls Operation

Generic Building Automation System Module (GBAS) Option

The generic building automation system module (GBAS) provides broad control capabilities for building automation systems other than Trane’s Tracer® system. A field provided potentiometer or a 0-5 vdc signal can be applied to any of the inputs of the GBAS to provide the following inputs and outputs.

• GBAS Analog Inputs

Four analog inputs that can be configured to be any of the following:

(1)Occupied zone cooling

(2)Unoccupied zone cooling

(3)Occupied zone heating

(4)Unoccupied zone heating

(5)SA cooling setpoint

(6)SA heating setpoint

(7)Space static pressure setpoint

(8)SA static pressure setpoint

• GBAS Binary Outputs

Each of the five (5) relay outputs can be mapped to any/all of the available diagnostics.

• Demand Limiting Binary Input

This function is operational on units with a GBAS and is used to reduce electrical consumption at peak load times. There are two types of demand limiting, 50% and 100%. When demand limiting is needed, mechanical cooling and heating operation are either partially (50%), or completely disabled (100%) to save energy.The demand limit definition is user definable at the human interface panel. Demand limit binary input accepts a field supplied switch or contact closure. When the need for demand limiting has been discontinued, the unit’s cooling/ heating functions will again become fully enabled.

Evaporator Coil Frost Protection

FROSTAT™

A temperature sensor on the evaporator is used to determine if the coil is getting close to a freezing condition. Mechanical cooling capacity is shed as necessary to prevent icing.

The FROSTAT™ system eliminates the need for hot gas bypass and adds a suction line surface temperature sensor mounted near the TXV bulb location to shut off the cooling when coil frosting conditions occur.The supply fan is not

shut off and will de-ice the coil.Timers prevent the compressors from rapid cycling.

Occupied/Unoccupied Switching There are four ways to switch occupied/ unoccupied:

(1)Programmable night setback sensor

(2)Field-supplied contact closure (hardwired binary input to RTM)

(3)Tracer®

(4)Factory-mounted time clock

•Field Supplied Occupied/Unoccupied input on the RTM

This input accepts a field supplied switch or contacts closure such as a time clock.

•Trane Tracer® System

TheTraneTracer® system can control the occupied/unoccupied status of the self- contained unit.

•Factory MountedTime Clock A time clock can control the occupied/unoccupied status of the self-contained unit.

Timed Override Activation - ICS

This function is operational whenever the unit’s RTM module board is used as the zone temperature sensor source, which can be set at the human interface panel. When this function is initiated by the push of the override button on the zone sensor, the unit will switch to the occupied mode. Unit operation (occupied mode) during timed override is terminated by a signal from Tracer®.

Timed Override Activation - Non-ICS This function is active whenever the unit’s RTM module board is selected as the zone temperature source, which can be set at the human interface panel. When this function is initiated by the push of the override button on the zone sensor, the unit will switch to the occupied mode. Automatic cancellation of the timed override mode occurs after three hours of operation.

Low Ambient Compressor Lockout This function will lock out the compressor if the outdoor air temperature is below the low ambient compressor lock-out temperature setpoint when using a field- installed outside air sensor.This setpoint is adjustable at the human interface panel. Compressors will lock out when outdoor air temperature falls below that selected temperature and will start again

when the temperature rises 5 F above the setpoint.

Comparative Enthalpy Control of Airside Economizer Option

An optional comparative enthalpy system is used to control the operation of the economizer and measures the temperature and humidity of both return air and outside air to determine which source has lower enthalpy.This system allows true comparison of outdoor air and return air enthalpy by measurement of outdoor and return air temperatures and humidities.

Note: If comparative enthalpy is not ordered, the standard method compares outdoor air enthalpy with a fixed reference enthalpy, set through the human interface panel.

Compressor Lead/Lag

Compressor lead/lag is a user-selectable feature through the human interface panel available on all units. After each request for compressor operation, the lead refrigeration circuit or compressor switches, thereby causing a more equitable or balanced run time among compressors.

Emergency Stop Input

A binary input is provided on the unit’s RTM module board for installation of a field-provided switch or contacts to immediatly shutdown all unit functions.

Water Flow Control

With compatible piping configurations, the unit can be configured to provide:

1)Constant water flow with basic or intermediate piping or 2) Variable water flow with intermediate piping only.

Constant water flow is for condenser pumping systems that are not capable of unloading the water-pumping system. Variable water flow maximizes energy saving by unloading the water pumping system.

Head Pressure Control

• Water-Cooled Condensers

Units that are set up for variable water flow will modulate a water valve to maintain a user-defined condensing temperature setpoint. Condensing temperature will be referenced utilizing factory installed sensors located at each condenser.

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