York D2CE, D2CG manual Factory-Installedoptions, Economizers, Power Exhaust

036-21359-001-B-0302

All supply air blowers are equipped with a belt drive that can be adjusted to meet the exact requirements of the job. A high speed drive accessory is available for applications with a higher CFM and/or static pressure requirement.

All compressors include internal pressure relief. Every refrigerant circuit includes an expansion valve, a liquid line filter-drier, a discharge line high pressure switch and a suction line with a freezestat and low pressure/ loss of charge switch. The unit control circuit includes two 75 VA transformers, two 24-volt circuit breakers and a relay board with two compressor lockout circuits, a terminal strip for thermostat wiring, plus an additional set of pin connectors to simplify the interface of addi- tional field controls.

All 208/230 and 460-volt models are ETL approved. All 208/230 and 575-volt models are CGA approved.

All models include a 1-year limited warranty on the complete unit. Compressors and electric heater ele- ments carry an additional 4-year warranty. Aluminized steel tubular heat exchangers carry an additional 9- year warranty.

All gas heat models are built with two heating sections for two equal stages of capacity control. Each section includes a durable heat exchanger with aluminized steel tubes, a redundant gas valve, spark ignition, power venting, an ignition module for 100% shut-off and all of the safety controls required to meet the latest ANSI standards.

The gas supply piping can be routed into the heating compartment through a hole in the base pan of the unit or through a knockout in the piping panel on the front of the unit.

All electric heat models are wired for a single power source and include a bank of nickel chromium ele- ments mounted at the discharge of the supply air blower to provide a high velocity and uniform distribu- tion of air across the heating elements. Every element is fully protected against excessive current and temper- ature by fuses and two thermal limit switches.

The power supply wiring can be routed into the control box through a threaded pipe connection in the base pan of the unit or through a knockout in the wiring panel on the front of the unit.

All internal factory wiring is color coded and numbered for ease in servicing and troubleshooting.

FACTORY-INSTALLED OPTIONS

ECONOMIZERS

Interlocked outdoor and return air dampers are posi- tioned by a fully modulating, spring return damper actu- ator capable of introducing up to 100% outdoor air with nominal 1% leakage type dampers. As the outdoor air intake dampers open, the return air dampers close. The changeover from compressor to economizer cool- ing is determined by one or two solid state enthalpy controls.

On single enthalpy, an outdoor air sensor determines when the outdoor air is cool and dry enough to provide “free” cooling. On differential enthalpy, one sensor monitors the outdoor air while a second sensor moni- tors the return air. Whenever the outdoor air is cooler and drier than the return air, the unit will switch to econ- omizer operation. For either option, the first compres- sor stage can provide additional cooling during economizer operation if the room thermostat calls for second stage.

The dampers and controls are installed and wired at the factory. Only the accessory rain hood needs to be assembled and installed in the field.

These economizer options can be used on all duct con- figurations.

POWER EXHAUST

Both the single and differential 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 condi- tioned space from being over-pressurized during econ- omizer operation.

The exhaust fan, motor and controls are installed and wired at the factory. Only the back-draft damper assembly needs to be field installed and the accessory rain hoods need to be assembled and installed in the field.

The power exhaust option can only be used on bottom duct configurations.

MOTORIZED OUTDOOR AIR INTAKE DAMPER

Interlocked outdoor and return air dampers are con- trolled by a 2-position, spring return damper actuator. The outdoor damper will open to some pre-set position whenever the supply air blower is operating and will drive fully closed when the blower shuts down.

The damper and controls are installed and wired at the factory. Only the accessory rain hood needs to be assembled in the field.

This damper option can be used on all duct configura- tions.

2 Unitary Products Group