CSZ ZP 16, Installation, Operation & Maintenance Manual, Page: 18 / 88

GENERAL DESCRIPTION
Page 2-2
REFRIGERATION/HEATING COMPONENTS
A. Refrigeration
ZP-Series chambers use one of three types of mechanical refrigeration systems. Single stage,
Tundra®, and cascade. A single stage system is used when the chamber’s ultimate low temperature
is -30ºF (-34ºC) or higher. The Tundra system is used when the chambers ultimate low temperature
is -50°F (-45°C) or higher. A cascade system is used when the chamber’s ultimate low temperature
is -94ºF (-70ºC). The single stage system uses refrigerant R-404A. The cascade system uses
refrigerant R-404A in System #1 and R-508B/R-23 in System #2. The Tundra System uses refrigerant
R-410A.
The refrigeration system can either be air cooled or water cooled depending on the model of chamber.
Standard ZP-Series chambers are air cooled except up to 3.5HP.
Chambers with compressors which are 10 HP (having nominally approx. 12kW of capacity with
R-404A refrigerant at 60 Hz operation) and larger are water cooled.
All refrigeration components are selected to ensure safe, reliable, and balanced operation. The
components may be purchased from the CSZ Service Department or a local refrigeration wholesaler.
B. Heating
Open-coil nichrome heating elements are standard on all systems. The heaters are mounted in
porcelain insulators attached to stainless steel frames. The heaters are located behind the rear
plenum and do not radiate directly into the test space.
Limited temperature sheath heaters are an option for chambers that may contain fl ammable vapors.
See the last section of this chapter for more information.