York MILLENNIUM YCAS0623

Questions and Answers

S
Sandra HarrisJul 26, 2025
How to troubleshoot no display on York Chiller panel?
- D
  Danielle AlexanderJul 26, 2025
  If the panel on your York Chiller isn't displaying anything and the unit won't start, there are several potential causes. First, check if the main supply to the control system is switched OFF and switch it ON if it is safe to do so. Next, see if any emergency stop devices are activated and turn them to the ON position if safe. Also, an undervoltage relay might have tripped, so check the mains supply. Check the emergency stop switch fuses, if there is no supply to - T3. If there's no 24VAC supply to the power board, check the wiring from - T3 to the powerboard and fuse - F3. Finally, if there's no +12V output from the powerboard, replace the powerboard or isolate any excessive load on the board.
C
Courtney SextonJul 30, 2025
Why does my York Chiller display SYS # HIGH OIL TEMP?
- T
  Thomas ChaneyJul 30, 2025
  If your York Chiller system displays 'HIGH OIL TEMP', it could be due to poor airflow through the condenser coils. Check for any airflow restrictions caused by blockages on the intake faces of the air coils. It could also be due to incorrect measured temperature, so check the sensor calibration, location, and wiring.
V
Victoria JamesAug 2, 2025
Why does my York MILLENNIUM YCAS0623 Chiller display HIGH AMBIENT TEMP?
- C
  Cathy Li MDAug 2, 2025
  If the York Chiller displays 'HIGH AMBIENT TEMP' fault, it could be due to several reasons. The ambient air temperature might be higher than the programmed operating limit; in this case, use the ‘ambient temp.’ key to display the temperature and confirm its accuracy. The warning should clear when the temperature falls below the limit. Also, ensure the programmed settings are correct for the unit's options. Another possibility is that residual heat isn't being dissipated, so verify the fan is operating and rotating correctly, and check for airflow recirculation. Finally, a faulty temperature reading could be the cause, so check the sensor's calibration, location, and wiring.
J
Jay AdamsAug 7, 2025
Why does my York Chiller display LOW AMBIENT TEMP?
- D
  Danielle SavageAug 7, 2025
  If your York Chiller shows 'LOW AMBIENT TEMP' fault, it could be due to a few reasons. The ambient air temperature might be lower than the programmed operating limit. Use the ‘ambient temp.’ key to display the temperature and confirm that the displayed value is approximately correct. The warning message should clear when the ambient air temperature rises above the programmed operating limit. Also, verify that the programmed settings are correct for the options fitted to the unit. A measured temperature might be incorrect, so check the sensor calibration, location, and wiring.
E
elizabeth15Aug 12, 2025
Why does my York Chiller display LOW WATER TEMP?
- K
  Kathleen RiveraAug 12, 2025
  If your York Chiller displays 'LOW WATER TEMP' fault, it could be due to a few reasons. The leaving liquid temperature may be dropping below the programmed low limit faster than the unit can unload, so check for restrictions and ensure stable liquid flow. Also, the unit might not be unloading, so check the supply to the unloader valve solenoid and verify the compressor unloads correctly. Finally, a faulty temperature reading could be the cause, so check the sensor's calibration, location, and wiring.
P
Patrick MatthewsAug 15, 2025
What to do if my York MILLENNIUM YCAS0623 displays VAC UNDERVOLTAGE?
- J
  jessica34Aug 15, 2025
  If your York Chiller displays 'VAC UNDERVOLTAGE' fault, it is likely due to a poor mains supply voltage. Check that the mains supply is stable and within allowable limits, and check for any voltage dips when the compressor starts.
J
Jasmin GarciaAug 20, 2025
What to do if York Chiller displays NO RUN PERM?
- T
  Tammy ElliottAug 20, 2025
  If your York Chiller displays 'NO RUN PERM', it means there is no run permissive. This could be because there is no liquid flow through the cooler, so ensure that liquid pumps are running, valves are correctly set, and flow is established. Another reason could be that the flow switch contacts are not made, so check that the flow switch is functional and installed according to the manufacturer’s instructions. Note that on some systems the pump starter may be wired to the unit and controlled to start by the unit.

Summary

SECTION 1 GENERAL CHILLER INFORMATION & SAFETY

Introduction

Overview of the chiller's purpose and intended use in HVAC systems.

Warranty

Details York's warranty coverage for equipment and materials.

Safety

Covers general safety guidelines and precautions for operating personnel.

Responsibility for Safety

Outlines the primary responsibilities of personnel working with the unit.

About this Manual

Explains document terms and intended use for operators and technicians.

Misuse of Equipment

Warns against improper use and operation outside specified parameters.

Emergency Shutdown

Describes the procedure for immediate shutdown in critical situations.

Material Safety Data

Provides safety information for refrigerants and associated materials.

SECTION 2 PRODUCT DESCRIPTION

Introduction

Introduces the YORK Millennium YCAS air-cooled screw chillers.

General Description

Describes the chiller's components and overall design.

Compressor

Details the semi-hermetic rotary twin-screw compressor features.

Cooler

Describes the Shell-and-Tube, Direct Expansion Evaporator.

SECTION 3 HANDLING AND STORAGE

Delivery and Storage

Provides precautions for unit storage before installation.

Inspection

Outlines steps for inspecting the unit upon delivery for damage.

Moving the Chiller

Details safe procedures for lifting and moving the unit.

SECTION 4 INSTALLATION

Location Requirements

Specifies site requirements for optimal performance and service access.

Outdoor Installations

Discusses considerations for ground level or rooftop installations.

Indoor Installations

Covers requirements for installing the unit in an enclosed plant room.

Location Clearances

Details necessary clearances for airflow and maintenance access.

Installation of Vibration Isolators

Provides instructions for installing optional vibration isolation mounts.

Shipping Braces

Notes that the chiller design does not require shipping braces.

Pipework Connection

Offers recommendations for satisfactory unit piping installation.

Water Treatment

Advises on water quality and treatment for optimal heat exchanger performance.

Pipework Arrangement

Suggests a standard pipework layout for single unit installations.

Connection Types & Sizes

Refers to technical data for relevant connection sizes.

Cooler Connections

Describes standard chilled liquid connection types.

Refrigerant Relief Valve Piping

Recommends routing relief valve piping for safety.

Ductwork Connection

Provides recommendations for connecting ductwork to the fan discharge.

Electrical Connection

Details recommendations for safe and satisfactory unit electrical connection.

Power Wiring

Outlines requirements for all electrical wiring and cable routing.

Power and Control Panel Layouts

Illustrates the layout of internal power and control panels.

SECTION 5 COMMISSIONING

Preparation

Lists checks to be performed before unit start-up.

Preparation - Power Off

Details pre-checks with the unit power supply switched OFF.

First Time Start-up

Guides the initial start-up procedure for the chiller.

SECTION 6 OPERATION

General Description

Explains how the unit operates independently or with other systems.

Start-up

Describes the process for starting the chiller unit.

Normal Running and Cycling

Details automatic operations during normal running and cycling.

Shutdown

Explains how to stop the unit and the associated processes.

GENERAL SAFETY GUIDELINES

Safety Symbols

Explains the meaning of hazard warning symbols used throughout the document.

CHANGEABILITY OF THIS DOCUMENT

NOMENCLATURE

MISUSE OF EQUIPMENT

Suitability for Application

Clarifies the intended cooling applications for the unit.

Structural Support

Emphasizes the need for proper structural support for unit installation.

Mechanical Strength

Warns against applying external loads or mounting components on the unit.

General Access

Discusses the importance of restricted access to qualified personnel.

Pressure Systems

Highlights hazards associated with the unit's refrigerant pressure system.

Electrical

Details safety precautions related to the unit's electrical system.

ROTATING PARTS

SHARP EDGES

REFRIGERANTS AND OILS

HIGH TEMPERATURE AND PRESSURE CLEANING

EMERGENCY SHUTDOWN

MATERIAL SAFETY DATA

Safety Data

Summarizes toxicity, exposure, and first aid information for R22.

Stability and Reactions

Details stability, conditions to avoid, and hazardous reactions of R22.

Precautions and Protection

Outlines general precautions, ventilation, and personal protective equipment.

Spill and Disposal

Provides procedures for handling spills and disposing of materials.

Fire Data

Lists fire extinguishing data and recommended fire fighting equipment.

SECTION 7 TECHNICAL DATA

Temperatures and Flows

Provides minimum and maximum operating temperatures and flow rates.

Water Pressure Drop

Presents charts for cooler water pressure drop versus flow rate.

Glycol Correction Factors

Offers correction factors for pressure drop when using glycol solutions.

Physical Data

Lists key physical specifications and operating limitations of the unit.

Operating Limitations

Details the minimum and maximum operational parameters for the unit.

Sound Power Data

Provides preliminary sound power data in decibels (dBA).

R-22 Refrigerant

Lists physical data specific to units using R-22 refrigerant.

R-407 C Refrigerant

Lists physical data specific to units using R-407C refrigerant.

Electrical Data

Presents detailed electrical specifications and connection options.

Multiple Point Power Supply Connection

Details field wiring for multiple 3-phase power supplies.

Optional Single Point Power Supply Connection with Internal Unit Circuit Breakers

Describes single-point supply with internal circuit protection.

Optional Single Point Power Supply Connection to Factory Circuit Breaker

Outlines single-point supply to a factory circuit breaker.

Control Power Supply

Details options for unit control power supply connections.

Compressor Data

Provides maximum KW and amperage values for DXST compressors.

Fan Data

Lists nominal power, full load amps, and locked rotor amps for fans.

Electrical Notes & Legend

Explains electrical notes, abbreviations, and legends used.

Power Connection Options

Illustrates different power supply connection configurations.

Wiring Diagrams

Provides elementary diagrams for Across-The-Line start configurations.

Dimensions

Details unit dimensions in millimeters for various models.

YCAS0373 - YCAS0503

Provides specific dimensions for YCAS0373 through YCAS0503 models.

YCAS0543 - YCAS0623

Provides specific dimensions for YCAS0543 through YCAS0623 models.

YCAS0653

Provides specific dimensions for the YCAS0653 model.

Operating Weights - Aluminum Fin Coils

Lists operating weights for units with aluminum fin coils.

Isolator Selection - Aluminum Fin Coils

Provides isolator selection data for aluminum fin coils.

Operating Weights - Copper Fin Coils

Lists operating weights for units with copper fin coils.

Isolator Selection - Copper Fin Coils

Provides isolator selection data for copper fin coils.

Refrigerant Flow Diagram

Illustrates the refrigerant flow path through the chiller system.

Process and Instrumentation Diagram

Shows the process and instrumentation flow of the chiller.

Component Locations

Identifies the physical locations of major control panel components.

Compressor Components

Details the internal components of the screw compressor.

SECTION 8 START-UP

System Startup Checklist

A checklist for all steps required before initial chiller start-up.

SECTION 9 MICROPANEL

Chiller Control Panel Programming & Data Access

Overview of accessing and programming the chiller control panel.

Display and Status Information Keys

Explains keys for viewing chiller operational status and faults.

Program & Setup Keys

Describes keys used for programming setpoints and system commands.

Introduction & Physical Description

Introduces the microprocessor control system and its interface.

Status Key & Fault Messages

Details status messages and fault warnings displayed by the system.

Display Keys & Option Switches

Explains keys for retrieving data and option switch settings.

Print Keys

Describes keys for accessing operating data and fault history printouts.

Entry Keys

Details keys used for changing programmed values in the chiller.

Setpoints Keys

Explains how to program chilled liquid temperature setpoints.

Clock Keys

Covers programming the internal clock and operating schedules.

Program Key

Guides programming of system parameters, cutouts, and timers.

SECTION 3 HANDLING AND STORAGE

Delivery and Storage

Provides precautions for unit storage before installation.

Inspection

Outlines steps for inspecting the unit upon delivery for damage.

Moving the Chiller

Details safe procedures for lifting and moving the unit.

SECTION 4 INSTALLATION

Location Requirements

Specifies site requirements for optimal performance and service access.

Outdoor Installations

Discusses considerations for ground level or rooftop installations.

Indoor Installations

Covers requirements for installing the unit in an enclosed plant room.

Location Clearances

Details necessary clearances for airflow and maintenance access.

Installation of Vibration Isolators

Provides instructions for installing optional vibration isolation mounts.

Shipping Braces

Notes that the chiller design does not require shipping braces.

Pipework Connection

Offers recommendations for satisfactory unit piping installation.

Water Treatment

Advises on water quality and treatment for optimal heat exchanger performance.

Pipework Arrangement

Suggests a standard pipework layout for single unit installations.

Connection Types & Sizes

Refers to technical data for relevant connection sizes.

Cooler Connections

Describes standard chilled liquid connection types.

Refrigerant Relief Valve Piping

Recommends routing relief valve piping for safety.

Ductwork Connection

Provides recommendations for connecting ductwork to the fan discharge.

Electrical Connection

Details recommendations for safe and satisfactory unit electrical connection.

Power Wiring

Outlines requirements for all electrical wiring and cable routing.

Power and Control Panel Layouts

Illustrates the layout of internal power and control panels.

SECTION 5 COMMISSIONING

Preparation

Lists checks to be performed before unit start-up.

Preparation - Power Off

Details pre-checks with the unit power supply switched OFF.

First Time Start-up

Guides the initial start-up procedure for the chiller.

SECTION 6 OPERATION

General Description

Explains how the unit operates independently or with other systems.

Start-up

Describes the process for starting the chiller unit.

Normal Running and Cycling

Details automatic operations during normal running and cycling.

Shutdown

Explains how to stop the unit and the associated processes.

GENERAL SAFETY GUIDELINES

Safety Symbols

Explains the meaning of hazard warning symbols used throughout the document.

CHANGEABILITY OF THIS DOCUMENT

NOMENCLATURE

MISUSE OF EQUIPMENT

Suitability for Application

Clarifies the intended cooling applications for the unit.

Structural Support

Emphasizes the need for proper structural support for unit installation.

Mechanical Strength

Warns against applying external loads or mounting components on the unit.

General Access

Discusses the importance of restricted access to qualified personnel.

Pressure Systems

Highlights hazards associated with the unit's refrigerant pressure system.

Electrical

Details safety precautions related to the unit's electrical system.

ROTATING PARTS

SHARP EDGES

REFRIGERANTS AND OILS

HIGH TEMPERATURE AND PRESSURE CLEANING

EMERGENCY SHUTDOWN

MATERIAL SAFETY DATA

Safety Data

Summarizes toxicity, exposure, and first aid information for R22.

Stability and Reactions

Details stability, conditions to avoid, and hazardous reactions of R22.

Precautions and Protection

Outlines general precautions, ventilation, and personal protective equipment.

Spill and Disposal

Provides procedures for handling spills and disposing of materials.

Fire Data

Lists fire extinguishing data and recommended fire fighting equipment.

SECTION 7 TECHNICAL DATA

Temperatures and Flows

Provides minimum and maximum operating temperatures and flow rates.

Water Pressure Drop

Presents charts for cooler water pressure drop versus flow rate.

Glycol Correction Factors

Offers correction factors for pressure drop when using glycol solutions.

Physical Data

Lists key physical specifications and operating limitations of the unit.

Operating Limitations

Details the minimum and maximum operational parameters for the unit.

Sound Power Data

Provides preliminary sound power data in decibels (dBA).

R-22 Refrigerant

Lists physical data specific to units using R-22 refrigerant.

R-407 C Refrigerant

Lists physical data specific to units using R-407C refrigerant.

Electrical Data

Presents detailed electrical specifications and connection options.

Multiple Point Power Supply Connection

Details field wiring for multiple 3-phase power supplies.

Optional Single Point Power Supply Connection with Internal Unit Circuit Breakers

Describes single-point supply with internal circuit protection.

Optional Single Point Power Supply Connection to Factory Circuit Breaker

Outlines single-point supply to a factory circuit breaker.

Control Power Supply

Details options for unit control power supply connections.

Compressor Data

Provides maximum KW and amperage values for DXST compressors.

Fan Data

Lists nominal power, full load amps, and locked rotor amps for fans.

Electrical Notes & Legend

Explains electrical notes, abbreviations, and legends used.

Power Connection Options

Illustrates different power supply connection configurations.

Wiring Diagrams

Provides elementary diagrams for Across-The-Line start configurations.

Dimensions

Details unit dimensions in millimeters for various models.

YCAS0373 - YCAS0503

Provides specific dimensions for YCAS0373 through YCAS0503 models.

YCAS0543 - YCAS0623

Provides specific dimensions for YCAS0543 through YCAS0623 models.

YCAS0653

Provides specific dimensions for the YCAS0653 model.

Operating Weights - Aluminum Fin Coils

Lists operating weights for units with aluminum fin coils.

Isolator Selection - Aluminum Fin Coils

Provides isolator selection data for aluminum fin coils.

Operating Weights - Copper Fin Coils

Lists operating weights for units with copper fin coils.

Isolator Selection - Copper Fin Coils

Provides isolator selection data for copper fin coils.

Refrigerant Flow Diagram

Illustrates the refrigerant flow path through the chiller system.

Process and Instrumentation Diagram

Shows the process and instrumentation flow of the chiller.

Component Locations

Identifies the physical locations of major control panel components.

Compressor Components

Details the internal components of the screw compressor.

SECTION 8 START-UP

System Startup Checklist

A checklist for all steps required before initial chiller start-up.

SECTION 9 MICROPANEL

Chiller Control Panel Programming & Data Access

Overview of accessing and programming the chiller control panel.

Display and Status Information Keys

Explains keys for viewing chiller operational status and faults.

Program & Setup Keys

Describes keys used for programming setpoints and system commands.

Introduction & Physical Description

Introduces the microprocessor control system and its interface.

Status Key & Fault Messages

Details status messages and fault warnings displayed by the system.

Display Keys & Option Switches

Explains keys for retrieving data and option switch settings.

Print Keys

Describes keys for accessing operating data and fault history printouts.

Entry Keys

Details keys used for changing programmed values in the chiller.

Setpoints Keys

Explains how to program chilled liquid temperature setpoints.

Clock Keys

Covers programming the internal clock and operating schedules.

Program Key

Guides programming of system parameters, cutouts, and timers.

SECTION 3 HANDLING AND STORAGE

Delivery and Storage

Provides precautions for unit storage before installation.

Inspection

Outlines steps for inspecting the unit upon delivery for damage.

Moving the Chiller

Details safe procedures for lifting and moving the unit.

SECTION 4 INSTALLATION

Location Requirements

Specifies site requirements for optimal performance and service access.

Outdoor Installations

Discusses considerations for ground level or rooftop installations.

Indoor Installations

Covers requirements for installing the unit in an enclosed plant room.

Location Clearances

Details necessary clearances for airflow and maintenance access.

Installation of Vibration Isolators

Provides instructions for installing optional vibration isolation mounts.

Shipping Braces

Notes that the chiller design does not require shipping braces.

Pipework Connection

Offers recommendations for satisfactory unit piping installation.

Water Treatment

Advises on water quality and treatment for optimal heat exchanger performance.

Pipework Arrangement

Suggests a standard pipework layout for single unit installations.

Connection Types & Sizes

Refers to technical data for relevant connection sizes.

Cooler Connections

Describes standard chilled liquid connection types.

Refrigerant Relief Valve Piping

Recommends routing relief valve piping for safety.

Ductwork Connection

Provides recommendations for connecting ductwork to the fan discharge.

Electrical Connection

Details recommendations for safe and satisfactory unit electrical connection.

Power Wiring

Outlines requirements for all electrical wiring and cable routing.

Power and Control Panel Layouts

Illustrates the layout of internal power and control panels.

SECTION 5 COMMISSIONING

Preparation

Lists checks to be performed before unit start-up.

Preparation - Power Off

Details pre-checks with the unit power supply switched OFF.

First Time Start-up

Guides the initial start-up procedure for the chiller.

SECTION 6 OPERATION

General Description

Explains how the unit operates independently or with other systems.

Start-up

Describes the process for starting the chiller unit.

Normal Running and Cycling

Details automatic operations during normal running and cycling.

Shutdown

Explains how to stop the unit and the associated processes.

GENERAL SAFETY GUIDELINES

Safety Symbols

Explains the meaning of hazard warning symbols used throughout the document.

CHANGEABILITY OF THIS DOCUMENT

NOMENCLATURE

MISUSE OF EQUIPMENT

Suitability for Application

Clarifies the intended cooling applications for the unit.

Structural Support

Emphasizes the need for proper structural support for unit installation.

Mechanical Strength

Warns against applying external loads or mounting components on the unit.

General Access

Discusses the importance of restricted access to qualified personnel.

Pressure Systems

Highlights hazards associated with the unit's refrigerant pressure system.

Electrical

Details safety precautions related to the unit's electrical system.

ROTATING PARTS

SHARP EDGES

REFRIGERANTS AND OILS

HIGH TEMPERATURE AND PRESSURE CLEANING

EMERGENCY SHUTDOWN

MATERIAL SAFETY DATA

Safety Data

Summarizes toxicity, exposure, and first aid information for R22.

Stability and Reactions

Details stability, conditions to avoid, and hazardous reactions of R22.

Precautions and Protection

Outlines general precautions, ventilation, and personal protective equipment.

Spill and Disposal

Provides procedures for handling spills and disposing of materials.

Fire Data

Lists fire extinguishing data and recommended fire fighting equipment.