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50 JOHNSON CONTROLS

FORM 160.80-EG1 (511)

GENERAL

Furnish and install where indicated on the drawings

YORK YS Rotary Screw Liquid Chilling Units(s). Each

unit shall produce a capacity of tons, cooling

GPM of from °F to °F when supplied

with GPM of condenser water at °F. Power

input shall not exceed kW with an IPLV (APLV)

of . The evaporator shall be selected for ft

°F hr/BTU fouling factor and a maximum liquid pressure

drop of ft. Water side shall be designed for 150

psig working pressure. The condenser shall be selected

for fouling factor and maximum liquid pressure

drop of ft. Water side shall be designed for 150

psig working pressure. Power shall be supplied to the

compressor motor at volts – 3-phase – (60)(50)

Hertz and controls at 115 volts –1-phase – (60)(50) Hertz.

– (or) –

Furnish and install where indicated on the drawings

YORK YS Rotary Screw Liquid Chilling Units(s). Each unit

shall produce a capacity of kW, cooling L/S

of from °C to °C when supplied with

L/S of condenser water at °C. Power input shall

not exceed kW with an IPLV (APLV) of . The

evaporator shall be selected for M

°C/W fouling

factor and a maximum liquid pressure drop of kPa.

Water side shall be designed for 1034 kPa working

pressure. The condenser shall be selected for M

°C/W fouling factor and maximum liquid pressure drop of

kPa. Water side shall be designed for 1034 kPa working

pressure. Power shall be supplied to the compressor

motor at volts – 3-phase – 50 Hertz and controls

at 115 volts – 1-phase – 50 Hertz.

Performance shall be certied or rated in accordance

with the latest edition of AHRI Standard 550/590-98 as

applicable. Only chillers that are listed in the AHRI Cer-

tication Program for Water Chilling Packages using the

vapor compression cycle are acceptable.

Each unit shall be completely factory packaged including

evaporator, condenser, subcooler, oil separator, compres-

sor, open motor, lubrication system, OptiView Control

Center, Solid State Starter, refrigerant isolation valves

and all interconnecting piping and wiring. The factory

package shall consist of a “Leaktight” design, with no pipe

thread connections that can loosen and leak over time. All

units shall ship with a full charge of refrigerant (HCFC-22

or HFC-134a) and oil. (Alternatively, the chiller shall be

shipped with the compressor, control panel and oil sepa-

rator removed (Form 3) or also with the shells separated

(Form 7) to allow rigging into the equipment room. All units

that ship disassembled shall be assembled and factory

run tested prior to disassembly and shipment).

COMPRESSOR

The compressor shall be an open-drive, rotary-screw type.

The compressor housing shall be of cast iron, precision

machined to provide minimal clearance for the rotors. The

rotors shall be manufactured from forged steel and use

asymmetric proles operating at a maximum speed of

(3570 RPM/60 Hz) (2975 RPM/50 Hz). The compressor

shall incorporate a complete anti-friction bearing design

to reduce power and increase reliability; four separate

cylindrical roller bearings to handle radial loads; and two

4-point angular contact ball bearings to handle axial loads.

A spring actuated positive seating check valve shall be

incorporated in the compressor housing to prevent rotor

backspin during shutdown. The open-drive compres-

sor shaft seal consists of a bellows-type spring loaded

precision lapped ceramic ring, Teon

static seal, and a

precision lapped ceramic rotating collar. The seal cavity is

maintained at intermediate pressure with its oil discharged

to the oil drain from the compressor. Combining intermedi-

ate pressure with direct oil injection provides cool, non-

foaming lubricant to the seal which assures a long life.

Capacity control shall be achieved by use of a slide

valve to provide fully modulating control from 100% to

10% of full load. The slide valve shall be actuated by oil

pressure, controlled by external solenoid valves through

the OptiView Control Center. The unit shall be capable

of operating with lower temperature cooling tower water

during part-load operation in accordance with AHRI Stan-

dard 550/590. If the unit can not operate at the minimum

load, the manufacturer shall provide a hot-gas-bypass

system to allow operation at 10% load, and advise the

minimum load and power input of the unit at the point

hot-gas-bypass is actuated.

LUBRICATION SYSTEM

An adequate supply of oil shall be available to the com-

pressor at all times. During start-up and coastdown, this

shall be achieved by oil reservoirs in the compressor.

During operation, oil shall be delivered by positive system

pressure differential.

All chillers shall be provided with a single oil lter hous-

ing with isolation valves. An optional dual lter is avail-

able which allows immediate switching from one lter

to the other, eliminating downtime during lter changes.

The off-line oil lter must be capable of being changed

Guide Specications

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York YS Specifiche Pagina 50

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