York YLUA Series Operation Manual page 6

Microcomputer Control Center - continued
• Discharge Air Temperature Reset via a YORK
ISN DDC or Building Automation System (by oth
ers) via:
- a pulse width modulated (PWM) input as standard
- a 4-20 milliamp or 0 -10 VDC input, or contact closure
with the optional B.A.S. interface option
• Anti-recycle timer status for each system
• Anti-coincident system start timer condition
• Compressor run status
• No cooling load condition
• Day, date and time
• Daily start/stop times
• Holiday status
• Automatic or manual system lead/lag control
(Discharge Air Temperature control only)
• Automatic lead/lag of compressors within a system
• Compressor starts & operating hours (each compres-
sor)
• Status of hot gas valves, and fan operation
• Run permissive status
• Number of compressors running
• Liquid solenoid valve status
• Load & unload timer status
Provisions are included for: pumpdown at shutdown;
optional remote discharge air temperature reset and two
steps of demand load limiting from an external building
automation system. Unit alarm contacts are standard.
FIG. 2 – POWER PANEL
6
The operating program is stored in non-volatile memory
(EPROM) to eliminate chiller failure due to AC powered
failure/battery discharge. Programmed setpoints are re-
tained in lithium battery-backed RTC memory for 5 years
minimum.
Ambient Kit (High) – Required if units are to operate when
the ambient temperature is above 115°F (46°C). Includes
sun shield panels and discharge pressure transducers.
(This option includes the Discharge Pressure Transducer
/Readout Capabil ity option). (Field mounted).
COMMUNICATIONS
• Native communication capability for N2, BACnet (MS/
TP) and Modbus
• Optional communciation available for LON via eLink
option
POWER PANEL
Each panel contains:
• Compressor power terminals
• Compressor motor starting contactors per
l.E.C.*
• Control power terminals to accept incoming for 115-
1-60 control power
• Fan contactors & overload current protection
The power wiring is routed through liquid-tight conduit to
the compressors and fans.
* International Electrotechnical Commission
FORM 150.63-EG4 (1012)
JOHNSON CONTROLS