Carrier 69NT40-511-199 manual Suction Solenoid Valve, Operation, Suction Solenoid Override

2.10 SUCTION SOLENOID VALVE

The suction solenoid valve, shown in Figure 2-5, is controlled by the Controller relay (TS).

a. Operation

If set point is below -10_C (+14_F), or -5_C (+23_F) optionally, and the suction solenoid valve override is not activated, Controller relay (TS) closes to energize the suction solenoid valve (SSV). Once opened, the refrigerant flow rate and unit cooling capacity is increased.

If set point is above -10_C (+14_F), or -5_C (+23_F) optionally, the suction solenoid valve opens during the temperature pulldown period unless the current limiting suction solenoid overrides or compressor reliability enhancement logic restricts its use. A pulldown period begins when the control temperature is more than 5_C (+9_F) above set point, and ends as soon as the control temperature equals set point.

For both conditions above, at the instant when the SSV opens, the SMV will drop to 20% open, then gradually increase to 100% open. Unless the current limiting suction solenoid overrides or compressor reliability enhancement logic (CREL) restricts its use.

b. Suction Solenoid Override

The suction solenoid override function restricts the opening of the suction solenoid valve (SSV) under certain high ambient and/or box temperature conditions to prevent compressor overload under these high capacity conditions. If the primary return sensor (RTS) fails (alarm code AL56), the suction solenoid valve will not open unless the ambient temperature is less than 10_C (50_F). If the ambient sensor fails (AL57), the suction solenoid valve will not be allowed to open until the return air temperature is less than 1.67_C (35_F). If both the ambient and return air (RTS) sensors fail, the suction solenoid valve will not be allowed to open until at least one of the sensors is repaired.

2.11 REMOTE MONITORING (Optional)

NOTE

The in-range light will be illuminated if the container control air temperature is within the tolerance selected. Refer to section 3.1.4 (Code 30).

When the remote monitor plug is connected to the remote monitoring receptacle, the following remote circuits are energized:

CIRCUIT	FUNCTION
Sockets B to A	Energizes remote cool light
Sockets C to A	Energizes remote defrost light
Sockets D to A	Energizes remote in-range light

T-268-07 2-18