RH CGS-240, Руководство пользователя

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Subsystems
CGS-240 Manual 6/15/2021
Page 66 of 148
Figure 6.24
then metered into the evaporator via the Sat Cool solenoid and chamber cool solenoid, absorbing heat (cooling) as
it expands to a low-pressure gas. The low pressure, heat-laden gas is then returned to the suction side of the
R134A compressor where the process repeats itself. This refrigerant suction side pressure is measured by a
pressure transducer, Prl. The refrigerant high side pressure is measured by a pressure transducer, Prh.
The Sat Cool solenoid is controlled by the ECB using pulse width modulation based on the bath temperature. The
Chamber Cool solenoid is controlled by the ECB using pulse width modulation based on chamber temperature.
6.4.1 COMPRESSOR
The R134A compressor is a hermetic refrigeration compressor, COMP1, which is capable of pulling to low
pressures on the input side, and producing high pressures on the discharge side.
During times of normal cooling demand, the compressor runs continuously. When there is no cooling demand for a
period of time, such as when the system is being heating to a warmer temperature, the compressor is turned off
completely until the system once again requires cooling control.
The refrigeration compressor is activated by ECB A0, activating the solid-state relay, SSR1, which applies AC power
to the compressor through circuit breaker, CB2. LEDs at ECB-A0 and SSR1 are lit when power is applied to the
compressor. Even with the LEDs on, power may be removed from the compressor by turning off CB2.
6.4.2 CONDENSER AND FAN
The refrigeration condenser cools the high-pressure high temperature gas output from the refrigeration
compressor, condensing it into a room temperature liquid. Heat from the condenser is exhausted into the room by
the condenser fan. The fan runs continuously whenever power is applied to the system provided the R-134A fan
CB1 is ON.
6.4.3 SAT COOL SOLENOID, SOL 6
The saturator temperature is maintained by heating or cooling the circulating
fluid as needed. Cooling is accomplished by refrigerant injection through the
sat cool solenoid valve, SSOL 6. This valve is actuated by a 24VDC pulse width
modulated signal. When energized, the valve opens allowing refrigerant to be
injected into the evaporator, causing it to cool the circulating fluid. The pulse
width of the valve directly controls the amount of refrigerant injected, thereby
affecting the temperature of the fluid. The valve is generally pulsed at a fixed
interval with varying
pulse width. When the system requires cooling, the ECB’s
DC CONTROL – RLY 5 sources 24 VDC to the sat cool solenoid, causing it to
open and inject refrigerant into the evaporator. An LED at RLY 5 also indicates
the relay status. When the LED is ON, the valve is energized. Saturator
temperature is measure by temperature probe, Ts.
6.4.4 CHAMBER COOL SOLENOID, SOL 7
The chamber temperature is maintained by heating or cooling the circulating
fluid as needed. Cooling is accomplished by refrigerant injection through the
sat cool solenoid valve, SOL 7. This valve is actuated by a 24VDC pulse width
modulated signal. When energized, the valve opens allowing refrigerant to be