- 12 -
1- Product description
Control switches
1. Thermo switch
A thermo switch is necessary. The following
specification is recommended.
Compressor OFF:
Evaporator fin surface temperature of 0°C
(32°F) or below.
The thermo switch is used to prevent the
evaporator from freezing.
2. Dual pressure switch
A dual pressure switch is necessary.
The
following
specifications
are
recommended.
Compressor OFF
• High pressure control
2.65 MPaG {27 kgf/cm
2
, 384 psig} or
higher
• Low pressure control
0.18 MPaG {1.8 kgf/cm
2
, 26 psig} or
lower
The dual pressure switch controls high and
low pressure.
• High pressure control
When abnormally high pressure develops,
the compressor is turned OFF to protect the
system.
• Low pressure control
When there is insufficient refrigerant in the
system, compressor operation is stopped to
prevent the compressor from seizing.
Gas type thermo switch
Capillary tube
ON
OFF
0.18 {1.8, 26}
2.65 {27, 384}
0.19 {1.9, 27} 1.47 {15, 213}
Operation temperature°C (°F)
ON
OFF
0 (32)
4 or 3(39 or 37)
DIFF