Specifications

82 Catalog WSC/WDC-4
C. Refrigerant Evaporator and Condenser:
1. Evaporator and condenser shall be of the shell-and-tube type, designed, constructed,
tested and stamped according to the requirements of the ASME Code, Section VIII.
Regardless of the operating pressure, the refrigerant side of each vessel will bear the
ASME stamp indicating compliance with the code and indicating a test pressure of 1.1
times the working pressure, but not less than 100 psig. Provide intermediate tube
supports at a maximum of 24 inch spacing.
2. Tubes shall be enhanced for maximum heat transfer, rolled into steel tube sheets and
sealed with Locktite® or equal sealer. The tubes shall be individually replaceable.
3. Provide isolation valves and sufficient volume to hold the full refrigerant charge in the
condenser or provide a separate pumpout system with storage tank..
4. The water sides shall be designed for a minimum of 150 psi or as specified elsewhere.
Vents and drains shall be provided.
5. Evaporator minimum refrigerant temperature shall be 33°F.
6. An electronic or thermal refrigerant expansion valve shall control refrigerant flow to
the evaporator. Fixed orifice devices or float controls with hot gas bypass are not
acceptable because of inefficient control at low load conditions. The liquid line shall
have a moisture indicating sight glass.
7. The evaporator and condenser shall be separate shells. A single shell containing both
vessel functions is not acceptable because of the possibility of internal leaks.
8. Reseating type spring loaded pressure relief valves according to ASHRAE-15 safety
code shall be furnished. The evaporator shall be provided with single or multiple
valves. The condenser shall be provided with dual relief valves equipped with a
transfer valve so one valve can be removed for testing or replacement without loss of
refrigerant or removal of refrigerant from the vessel. Rupture disks are not acceptable.
9. The evaporator, suction line, and any other component or part of a component subject
to condensing moisture shall be insulated with UL recognized 3/4 inch closed cell
insulation. All joints and seams shall be carefully sealed to form a vapor barrier.
10. Provide factory-mounted thermal dispersion flow switches on each vessel to prevent
unit operation with no flow.
D. Prime Mover: Squirrel cage induction motor of the hermetic type of sufficient size to
efficiently fulfill compressor horsepower requirements. Motor shall be liquid refrigerant
cooled with internal thermal overload protection devices embedded in the winding of each
phase. Motor shall be compatible with the starting method specified hereinafter. If the
Contractor chooses to provided an open drive motor or compressor, verify in the submittal
that the scheduled chiller room ventilation system will accommodate the additional heat
and maintain the equipment room at design indoor temperature based on 95°F outdoor
ambient ventilation air available.
If additional cooling is required, manufacturer shall be responsible for the installation,
wiring and controls of a cooling system. Chiller selection shall compensate for tonnage
and efficiency loss to make certain the owner is not penalized.
E. Motor Starter:
1. The main motor starter is to be factory mounted and fully wired to the chiller
components and factory tested during the run test of the unit.
-- OR --
The main motor starter is to be furnished by the chiller manufacturer and shipped
loose for floor mounting and field wiring to the chiller package. It shall be free-
standing with NEMA-1 enclosure designed for top entry and bottom exit and with
front access.
2. For open drive air-cooled motors the chiller manufacturer shall be responsible for
providing the cooling of the refrigeration machinery room. The sensible cooling
load shall be based on the total heat rejection to the atmosphere from the
refrigeration units.