VAV, power exhaust is energized by means of a binary out- put 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.
The power exhaust option can only be used on bot- tom duct configurations.
•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 oper- ating 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 AND CON- DENSER 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 sup- ply. These nickel chromium heater elements are pro- vided 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 available 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 oper- ate 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 cus- tomer-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 depend- ing on their size. In order to utilize the unit’s mounting
261660-YTG-C-0707
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 perpendicular wall which is not subjected to exces- sive temperature, vibration, humidity, dust, corrosive gas, explosive gas, etc., or within an appropriate enclo- sure rated for outside installation to safeguard against moisture, dust and excessive 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 oper- ation, 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 evapo- rator pressure. HGBP is standard on all units with VAV and optional with CV units.
•FILTER OPTIONS - Standard units are shipped with 2” throw-away filters installed. 2” pleated and 4” pleated fil- ters are offered as a factory installed option.
•CONVENIENCE OUTLET - This 110 volt outlet can be “powered” by the unit with a stepdown transformer or you may order the unit with a “non-powered” conve- nience outlet that can be wired in the field.
•DISCONNECT SWITCH - For gas heat units and cooling units with electric heat, a HACR breaker sized to the unit is provided. For cooling only units, a switch sized to the largest electric heat available for the particular unit is provided. Factory installed option only.
•DOUBLE WALL CONSTRUCTION - Optional double wall construction is available to provide smooth inner surfaces for easy and effective cleaning to reduce risk of dirt and bacterial accumulation. Fiberglass insulation is sandwiched between heavy gauge steel sheets to form a durable, rigid casing to withstand higher working pres- sures and impact forces. The heavy-duty construction provides excellent acoustic and thermal insulation and eliminates erosion of insulation material and contamina- tion of the air stream.
•BAS - Building Automation System Controls (avail- able on two-system cooling product only).
Simplicity® INTELLI-Comfort™ CONTROL - The York® Simplicity® INTELLI-Comfort™ control is factory installed. It includes a supply air sensor, a return air sensor, and an outside air sensor. There are provisions for a field installed dirty filter indicator switch, an air-proving switch, an Out- side Air Humidity sensor, a Return Air Humidity sensor, an Inside IAQ sensor, and an Outside Air IAQ sensor. Con- struction mode operation, 365-day real time clock with 7 day programming plus holiday scheduling is built-in. Two different modes of demand ventilation are achieved through the INTELLI-Comfort™ using CO2 sensors. It
