Product data

7. Compressor safeties shall include high compres-
sor discharge temperature, high motor winding
temperature, low oil pressure, reverse rotation,
and high discharge pressure.
8. Compressorshallbeequipped with internal pres-
sure relief to protect against overpressure. For
compressors not equipped with internal pressure
relief, the high side of the chiller shall be pro-
tected with an external relief valve capable of
passing the full load flow produced by the
compressor.
9. Compressor shall be provided with a lubrication
system to deliver oil under pressure to the bear-
ings. System shall consist of:
a. Six-micron oil filter with isolation valves to
allow filter change without removal of refrig-
erant charge.
b. Oil sump heater (115/230 volt, single phase,
50 or 60 Hz), if required for proper opera-
tion. Heater shall be controlled by unit mi-
croprocessor and factory wired.
c. Positive oil flow sensing/verification to occur
through a float-type oil level sensor used in
conjunction with an oil pressure sensor.
Systems that rely on a flow switch to moni-
tor oil flow can be activated by the flow of
refrigerant vapor rather than oil and can give
an erroneous signal and are therefore
unacceptable.
10. Compressor shall be fully field serviceable. Com-
pressors which must be removed and returned
to the factory for service shall not be acceptable.
Manufacturer shall sign, on company letterhead,
a written statement confirming the ability of the
screw compressor to be field serviced.
11. Acoustical attenuation shall be provided, as re-
quired, to achieve a maximum (full load or part
load) sound level of [ ] dBA, measured per ARI
Standard 575 (latest edition). Attenuation shall
be designed to be easily removed and reinstalled.
C. Motor:
1. Compressor motors shall be of the semi-hermetic,
liquidrefrigerantcooled,singlespeed,non-reversing,
squirrel cage induction type suitable for the volt-
age shown on the equipment schedule.
2. Motors’ design speed shall be 3550 rpm at 60 Hz
or 2960 rpm at 50 Hz.
3. Motors shall be suitable for operation in a refrig-
erant atmosphere and shall be cooled by atomized
refrigerant in contact with the motor windings.
4. Motor stator shall be arranged for service or re-
movalwith only minorcompressor disassembly and
without breaking the main refrigerant piping
connections.
5. Full load operation of the motor shall not exceed
nameplate rating.
6. Low-voltage motors (600 v or less) shall be suit-
able for connection to wye-delta type reduced in-
rush or solid-state type reduced voltage starters.
7. If the mechanical contractor chooses to provide a
chiller with an open motor instead of the speci-
fied semi-hermetic motor, the contractor shall
either:
supply additional ventilation to maintain a maxi-
mum mechanical room temperature of 104 F
(40 C). Additional ventilation requirements shall
be calculated as follows:
(Full load motor kW) (0.05) (3413)
CFM =
(104−95) (1.08)
CFM = (FLkW motor) (17.6)
or, if the mechanical room is air conditioned, the
mechanical contractor shall install additional cool-
ing equipment to dissipate the motor heat as per
the following formula:
BTUH = (FLkW motor) (0.05) (3413)
BTUH = (FLkW motor) (171)
and, alternately
BTUH
TONS =
12,000
In either case, the additional piping, valves, air-
handling equipment, insulation, wiring, switch-
gear changes, ductwork, and coordination with
other trades shall be the responsibility of the me-
chanical contractor. Shop drawings reflecting any
changes to the design shall be included in the sub-
mittal and incorporated into the final as-built draw-
ings for the project.
Also, if an open motor is provided, a mechanical
room thermostat shall be installed and set at
104 F (40 C). If this temperature is exceeded, the
chillers shall shut down and an alarm signal shall
be generated to the central Energy Management
System (EMS) display module prompting the ser-
vice personnel to diagnose and repair the cause
of the over-temperature condition. The mechani-
cal contractor shall be responsible for all changes
to the design, including coordination with tem-
perature control, electrical, and other trades.
In addition, the electrical power consumption of
any auxiliary ventilation and/or mechanical cool-
ing required to maintain mechanical room condi-
tions as stated above shall be considered in the
determination of conformance to the scheduled
chiller energy efficiency requirement.
D. Cooler and Condenser:
1. Cooler and condenser shall be of shell and tube
type construction, each in separate shells. Units
shall be fabricated with high-performance tub-
ing, steel shell and tube sheets. Waterboxes shall
benozzle-in-headtype with nozzles either flanged
or with Victaulic grooves to allow for use of
Victaulic couplings.
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