MILLENNIUM CENTRIFUGAL LIQUID CHILLERS - Johnson …

1 26874 AMILLENNIUMCENTRIFUGAL LIQUID CHILLERSOPERATING & MAINTENANCES upersedes: Nothing1096 FORM YT G0 A1 B1 thru YT L6 D8 F2 (STYLE H)HCFC-123 (cooling only)WITH MICROCOMPUTER CONTROL CENTERSPART #371-01200-002, #371-01200-007 & 371-01200-014 FOR ELECTRO-MECHANICAL STARTER,SOLID STATE STARTER &WARNINGSYSTEM CONTAINS REFRIGERANT UNDER INJURY COULD RESULT IF PROPER PROCEDURES ARENOT FOLLOWED WHEN SERVICING SYSTEM. ALL SERVICE WORKSHALL BE PERFORMED BY A QUALIFIED SERVICE TECHNICIAN INACCORDANCE WITH YORK INSTALLATION/OPERATION SPEED DRIVE2 YORK INTERNATIONALTABLE OF CONTENTSS ection 1: Description of System and Operational Fundamentals.

2 4 Section 2: MicroComputer Control Center ..6 Introduction .. 6 Control Center .. 7 Operation .. 8 Programming the MicroComputer Control Center .. 13 Service Keys .. 18 Operating Modes .. 20 Compressor Switch .. 21 Display Messages .. 21 Section 3: System Operating Procedures ..28 Section 4: System Components Description - Compressor/Motor Assembly ..35 Section 5: Operational Maintenance ..39 Use of Pump Assisted Turboguard Purge Unit .. 39 Oil Return System .. 42 Charging the Unit With Oil .. 44 Section 6: Trouble Shooting ..46 Section 7: Maintenance ..52 Renewal Parts .. 52 Checking System for Leaks.

3 52 Evacuation and Dehydration of Unit .. 52 Refrigerant Charging .. 55 Checking the Refrigerant Charge During Unit Shut Down .. 55 Handling Refrigerant for Dismantling and Repairs .. 55 Megging the Motor .. 56 Condensers and Coolers .. 56 Compressor .. 59 Electrical Controls .. 59 Section 8: Preventive 59 NOTE: This instruction covers operation of CHILLERS equipped with Electro-Mechanical or Solid StateStarters. If chiller is equipped with Variable Speed Drive, Form is to be used inconjunction with this VARIABLE SPEED PARTS PARTS CONTROL PARTS B & C PARTS E PARTS F PARTS C3 (WITH EM STARTER) (WITH SOLID STATE STARTER) (WITH VARIABLE SPEED DRIVE) LITERATUREYORK INTERNATIONAL3 FORM 1 - YT chiller WITH ELECTRO-MECHANICAL STARTERFIG.

4 2 - YT chiller WITH VARIABLE SPEED DRIVE4 YORK INTERNATIONALSECTION 1 DESCRIPTION OF SYSTEM AND OPERATIONALFUNDAMENTALSing through the condenser tubes absorbs heat fromthe refrigerant vapor, causing it to condense. The con-denser water is supplied to the chiller from an externalsource, usually a cooling tower. The condensed refrig-erant drains from the condenser into the flow controlchamber, where the flow restrictor meters the flowof LIQUID refrigerant to the cooler to complete therefrigerant major components of a chiller are selected tohandle the refrigerant which would be evaporated atfull load design conditions.

5 However, most systemswill be called upon to deliver full load capacity for onlya relatively small part of the time the unit is in CONTROLThe major components of a chiller are selected for fullload capacities; therefore, capacity must be controlledto maintain a constant chilled LIQUID temperature leav-ing the cooler. Prerotation vanes (PRV), located at theentrance to the compressor impeller, compensate forvariation in load. (See Fig. 3 Detail A)The position of these vanes is automatically controlledthrough a lever arm attached to an electric motor lo-cated outside the compressor housing.

6 The automaticadjustment of the vane position in effect provides theperformance of many different compressors to matchvarious load conditions from full load with vanes wideopen to minimum load with vanes completely Variable Speed Drive units, the capacity is controlledby speed modulation as well as prerotation vane con-trol. The Variable Speed Drive selects the combinationof compressor motor speed and prerotation vane open-ing for the most efficient operation. (See Form )SYSTEM OPERATION DESCRIPTIONYORK Millenium CHILLERS are commonly applied to largeair conditioning systems, but may be used on other ap-plications.

7 The unit consists of an open motor mountedto a compressor (with integral speed increasing gears)condenser with purge unit, sub-cooler, cooler and flowcontrol chiller is controlled by a modern state of the artMicroComputer Control Center which monitors itsoperation. The control center is programmed by theoperator to suit job specifications. Automatic timed start-ups and shutdowns are also programmed to suitnighttime, weekends, and holidays. The operating sta-tus, temperatures, pressures, and other informationpertinent to operation of the chiller are automaticallydisplayed and read on a 40 character alphanumericmessage display.

8 Other displays can be observed bypressing the keys as labeled on the control chiller with the MicroComputer Control Center isapplied with an Electro-Mechanical Starter, a factorypackaged YORK Solid State Starter or a factory pack-aged Variable Speed Drive that produces even greaterefficiency and energy operation, a LIQUID (water or brine) to be chilled flowsthrough the cooler, where refrigerant, boiling at low pres-sure and temperature, absorbs heat from the water. Thechilled LIQUID is then piped to fan coil units or other airconditioning terminal units, where it flows through finnedcoils, absorbing heat from the air.

9 The warmed LIQUID isthen returned to the chiller to complete the chilled refrigerant vapor, which is produced by the boilingaction in the cooler, flows to the compressor where therotating impeller increases its pressure and tempera-ture and discharges it into the condenser. Water flow-YORK INTERNATIONAL5 FORM 3 - REFRIGERANT FLOW THROUGH CHILLERFIG. 3 (DETAIL A) - COMPRESSOR PREROTATION VANES7619A(D)FLOW CONTROLCOMPRESSORDISCHARGEDISCHARGEBAFFL ECONDENSERSUB-COOLERFLOWCONTROLCHAMBEREL IMINATORCOOLERSUCTIONLD00478 AOIL COOLER6 YORK INTERNATIONALS ection 2 MICROCOMPUTER CONTROL CENTERNOTE: This instruction covers operation of CHILLERS equipped with Electro-Mechanical or Solid State Starters.

10 Ifchiller is equipped with Variable Speed Drive, Form is to be used in conjunction with 4 - MICROCOMPUTER CONTROL CENTER AND KEYPAD CHILLED LIQUID TEMPERATURES - LEAVING ANDRETURN REFRIGERANT PRESSURES - EVAPORATOR ANDCONDENSER DIFFERENTIAL OIL PRESSURE CONDENSER LIQUID TEMPERATURES - OPTIONALFIELD INSTALLED - LEAVING AND RETURN OPTIONS PRINT HISTORY PRINT MOTOR CURRENT IN % OF FULL LOAD AMPS SATURATION TEMPERATURES - EVAPORATORAND CONDENSER DISCHARGE TEMPERATURE OIL TEMPERATURE PURGE PRESSURE SOLID STATE STARTER MOTOR CURRENT/ VOLTSThe YORK MicroComputer Control Center is a