Technical description
DRYPOINT RA 200 – 2500 NA
21
5.13. Refrigerant Pressure Switches P
A
-
P
B
-P
V
As operation safety and protection of the dryer a series of pressure switches are installed in the gas circuit.
PB : Low-pressure controller device on the pushing side (carter) of the compressor, is enabled only if the pressure
drops below the pre-set value. The values are automatically reset when the nominal conditions are restored.
Calibrated pressure :
R 404 A Stop 14.5 psig - Restart 72.5 psig
R 404 A Stop 1.0 barg - Restart 5.0 barg
PA :
This high-pressure controller device, located on the pushing side on the compressor, is activated when the
pressure exceeds the pre-set value. It features a manual-resetting button mounted on the controller itself.
Calibrated pressure :
R 404 A Stop 464 psig - Manual reset
R 404 A Stop 32 barg - Manual reset
PV : DRYPOINT RA 200-1250 NA Fan control pressure switch is placed at the discharge side of refrigeration
compressor. It keeps the condensation temperature/pressure constant within preset limits (Air-Cooled).
Calibrated pressure :
R 404 A Start 290 psig (113°F) - Stop 232 psig (97°F) - Tol erance
±
15 psi
R 404 A Start 20 barg (45°C) - Stop 16 barg (36°C) - Tolera nce
±
1 bar
PV
1
: DRYPOINT RA 1500-2500 NA
Fan control pressure switch is placed at the discharge side of refrigeration
compressor. It keeps the condensation temperature/pressure constant within preset limits (Air-Cooled) – Low
Speed.
Calibrated pressure :
R 404 A
Start 305 psig (117°F) - Stop 261 psig (104°F) - To lerance
±
14.5 psi
R 404 A
Start 21 barg (47°C) - Stop 18 barg (40°C) - Tolera nce
±
1 bar
PV
2
: DRYPOINT RA 1500-2500 NA
Fan control pressure switch is placed at the discharge side of refrigeration
compressor. It keeps the condensation temperature/pressure constant within preset limits (Air-Cooled) – High
Speed.
Calibrated pressure :
R 404 A
Start 334 psig (124°F) - Stop 297 psig (115°F) - T olerance
±
14.5 psi
R 404 A
Start 23 barg (51°C) - Stop 20.5 barg (46°C) - Tole rance
±
1 bar
5.14. Safety thermo-switch T
s
1
2
P
Q
S
0
0
0
5
To protect the operating safety and the integrity of the dryer, a thermo-switch (TS)
is installed on the refrigerant gas circuit. The thermo-switch sensor, in case of
unusual discharge temperatures, stops the refrigerating compressor before it is
permanently damaged.
Manually reset the thermo-switch only after the nominal operating conditions have
been restored. Unscrew the relative cap (see pos.1 in the figure) and press the
reset button (see pos.2 in the figure).
TS setting :
temperature 212 °F (+4 / -4 °F)
temperature 100 °C (+2 / -2 °K)
5.15. Compressor crankcase heater (DRYPOINT RA 600-2500 NA)
At low temperatures oil can more easily be mixed with the refrigerant gas. So, when the compressor starts, oil can be
drawn into the refrigeration circuit and liquid hammering could occur.
To prevent this, an electrical resistance heater is installed in the suction side of the compressor. When the system is
powered and the compressor is not running, this heater keeps the oil at the correct temperature.
This heater is controlled by a thermo-switch which prevents overheating the oil.
NOTE : The heater must be powered at least a couple of hours before the start up of the refrigeration compressor.
Содержание DRYPOINT RA 1000/AC NA
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