Flooded type water cooled screw chiller (PCB Control)
MCAC-CTSM-2012-11
49
convenience of heat transfer. Thermostatic insulation and enclosing measures shall be taken
for the temperature sensing device.
Inspect whether there is temperature deviation for the entering and leaving water temperature
sensor caused by insufficient heat transfer oil in the thermostatic pipe.
For later armored dip-type temperature sensor, no lubricating oil is required for heat transfer.
1.4 Complete Machine Performance Parameters Inspection
1) Parameters Inspection before Start-up
Before start-up of the unit, the following performance parameters need to be inspected:
(1) High/low voltage value of the system. For the unit shutdown and waterless in a long term, the
liquid and gas of the system shall be equivalent and close to the saturation pressure
corresponding to the current ambient temperature. The correlation of saturation temperatures
and pressures (the pressures in the list are gage pressures, among which, the atmospheric
pressure is 0.1MPa) of R22 and R134a refrigerant is shown in table 1:
In the pressure gauge scale, taking the right figure for example: the values outside of the black
circle are pressure values (unit: bar), and the values of the red, blue and green circles indicate
saturation temperatures of refrigerants R404A, R22 and R134a respectively under the relative
pressure. The types of refrigerants indicated in different pressure gauges might differ.
[Table 1]
Refrigerant
Temperature
℃
R134a Refrigerant Pressure (Gage
Pressure) MPa
0 0.19
5 0.25
10 0.32
In shutdown status,
the high and low
voltages shall be the
same and equal to the
saturation pressure
corresponding to the
current temperature.