York H2CA600 Installation Instruction

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air cooled

York H2CA600 Installation Instruction Manual pdf 1 page image

GENERALA Hot Gas Bypass valve is a fully modulating control that willprovide a metered flow of compressor discharge gas to thesystem’s evaporator coil during reduced load operation toprevent condensate from freezing on the surface of the evapo-rator coil.Hot Gas Bypass may be required when a CA condensing unitis applied on:1. A multi-zone (MZ) system,2. A throttling-type variable air volume (VAV) system,3. A system handling 100% outdoor air, or4. Any system where condensate may freeze on the surfaceof the evaporator coil during low load operation.NOTE: The need for hot gas bypass can be reduced oreliminated on some systems by splitting the coilsfor row control instead of face control.When hot gas bypass is required, York recommends that:1. One end of the main bypass line be connected to the inletof the evaporator coil between the expansion valve and thedistributor of the system’s first stage of capacity. This ar-rangement is required to maintain a high gas velocity andgood oil return through both the coil and the suction riserduring hot gas operation.2. The other end of the main bypass line be connected to the7/8" spud that is provided in the compressor dischargeheader of the condenser coil. On units with two independentsystems (models CA480 and 600), the bypass line shouldalways be connected to the #1 system. Although the #2system will also have a 7/8" spud connection, a second hotgas bypass line should not be required unless systems 1and 2 are applied with different evaporator units.3. A pilot-operated valve (an Alco FA8-13H or equal) be used.This valve includes a 24-volt solenoid which closes thebypass line and permits the system to shut down after thenormal pumpdown cycle. See Figure 1.NOTE: To use the recommended valve, the overall systemcontrol circuit and the evaporator coil must have asmany capacity stages as the CA unit and eachstage of the evaporator coil must be equipped withboth an expansion valve and a solenoid valve. If asystem is not designed to unload to its minimumcapacity, a larger hot gas bypass valve may berequired.4. A 1/4" pilot line be connected between the access port onthe hot gas bypass valve and one of the suction accessports on the compressor. Use either the one labeled A or Bon Figure 2. The access port labeled C will already beconnected to the system’s low pressure control.NOTE: When using port A, make the connection before thesystem is charged because refrigerant will be lostwhenever this access port is opened. Although thesuction stop valve can be backseated to close portB, port B may be needed for a suction pressurecontrol and/or a service connection.AIR COOLEDSPLIT-SYSTEM AIR CONDITIONERSINSTALLATION INSTRUCTION Supersedes: 550.12-N6 (579) 550.13-N6Y (399)HOT GAS BYPASSMODELS H2CA600®FIG. 1- ALCO PILOT-OPERATED VALVE - FA8-13H

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