FACTORY-INSTALLED OPTIONS
•SINGLE INPUT ELECTRONIC ENTHALPY ECONOMIZERS - Includes a slide-in /plug-in damper assembly with fully modulating spring-return motor actuator capable of introducing up to 100% outdoor air with nominal 1% leakage type dampers.
The enthalpy system contains one sensor that monitors the outdoor air and determines when the air is cool enough and dry enough to provide free cooling.
The rainhood is painted to match the basic unit and must be field-assembled before installing.
•BAS-READY ECONOMIZER - Includes a slide-in / plug-in damper assembly with fully modulating spring-return motor actuator with zero to 95-degree rotation capable of introducing up to 100% outdoor air with nominal 1% leak- age type dampers.
Actuator requires 2-10 VDC input from an external source, such as a field-installed or factory-installed BAS controller. BAS-ready actuators have an adjustable auxiliary end- switch for optional power exhaust control.
For units with optional VAV or Simplicity® Intelli-Comfort™ control, a factory-installed, dry bulb sensor determines if outdoor air temperature is low enough to provide free-cool- ing operation. (Field-installed humidity sensors for either outdoor air or outdoor & return air streams are available for single enthalpy and differential enthalpy configurations, respectively).
The rainhood is painted to match the basic unit and must be field-assembled before installing.
•POWER EXHAUST - Our economizer options are available with power exhaust. Whenever the outdoor air intake dampers are opened for free cooling, the exhaust fan will be energized to prevent the conditioned space from being over-pressurized during economizer operation. BAS-ready economizer actuators have an adjustable auxiliary end-switch to provide a range of damper positions available to energize power exhaust. For units with optional VAV, power exhaust is energized by means of a binary output signal from the unit's VAV control board.
The exhaust fan, motor and controls are installed and wired at the factory. The rain hood must be assembled and installed in the field.
•MOTORIZED OUTDOOR AIR INTAKE DAMPER - Includes a slide-in /plug-in damper assembly with a 2- position, spring return motor actuator which opens to a pre- set position whenever the supply air blower is operating and will drive fully closed when the blower unit shuts down.
The rain hood is painted to match the basic unit and must be field assembled before installing.
•BAROMETRIC RELIEF DAMPER - This damper option can be used to relieve internal building air pressure on units with an economizer without power exhaust. This accessory includes a rain hood, a bird screen and a fully assembled damper. With bottom duct connections, the damper should be mounted over the opening in the return
air panel. With horizontal ductwork, the accessory should be mounted on the return air duct.
•PHENOLIC COATED EVAPORATOR, REHEAT, AND CONDENSER COILS - Special coating process that utilizes Technicoat 10-1" processes. Coating is applied by total immersion of the complete coil for maximum protection.
•ELECTRIC HEATERS wired for single point power supply. These nickel chromium heater elements are provided with limit and automatic reset capability to prevent operation at excessive temperatures.
•VARIABLE AIR VOLUME (VAV) - A factory-installed variable frequency drive (VFD), mounted in the Blower Access compartment, is used to control the speed of the indoor blower motor in order to maintain a constant static pressure in the supply duct. A pressure transducer and VAV control board are mounted inside the control box. The drive comes completely wired and pre-programmed from the factory.
An optional, factory-installed manual bypass switch avail- able with factory-installed VFD can be found in the Blower Motor Access compartment. The switch can be used to either route power to the VFD for modulating control of the blower motor, to bypass the drive and operate the motor at full speed, or to power the drive (and not the motor) for diagnostic purposes.
Due to space limitations, VAV is not available with any of the factory-installed BAS options described below, but is available with ‘BAS-ready’ models. Terminal blocks are provided in the control box for field wiring of the customer- installed BAS.
A ‘VFD-ready’ option provides the provisions for a cus- tomer-installed drive. The unit comes with a mounting bracket installed in the Blower Access compartment which may accommodate other vendor’s drives depending on their size. In order to utilize the unit’s mounting bracket, the maximum recommended drive dimensions are as follows:
For 5-hp motor applications ........................13” H x 6” W x 7” D For 7.5 thru 15-hp motor applications .........13” H x 8” W x 8” D
If the drive will not fit in the allotted space, then it will have to be mounted elsewhere; either within the building on a per- pendicular wall which is not subjected to excessive temper- ature, vibration, humidity, dust, corrosive gas, explosive gas, etc., or within an appropriate enclosure rated for outside installation to safeguard against moisture, dust and exces- sive heat.
A terminal block located in the control box is provided for field connection of the VFD controls.
•HOT GAS BYPASS - To allow for low cooling load opera- tion, a direct-acting pressure-modulating bypass control valve installed on the system #1 discharge line is used to divert high temperature, high pressure refrigerant around the TXV in order to maintain a desired minimum evapora- tor pressure. HGBP is standard on all units with VAV and optional with CV units.
