Bryant F, 580J*08--14D appendix Protective Devices, Compressor Protection

	Table 3 – Detector Indicators
CONTROL OR INDICATOR	DESCRIPTION
Magnetic test/reset switch	Resets the sensor when it is in the alarm or trouble state. Activates or tests the sensor when it is in
	the normal state.
Alarm LED	Indicates the sensor is in the alarm state.
Trouble LED	Indicates the sensor is in the trouble state.
Dirty LED	Indicates the amount of environmental compensation used by the sensor
	(flashing continuously = 100%)
Power LED	Indicates the sensor is energized.

580J

Controller’s Power LED is Off

1.Make sure the circuit supplying power to the control- ler is operational. If not, make sure JP2 and JP3 are set correctly on the controller before applying power.

2.Verify that power is applied to the controller’s supply input terminals. If power is not present, replace or re- pair wiring as required.

Remote Test/Reset Station’s Trouble LED Does Not Flash When Performing a Dirty Test, but the Controller’s Trouble LED Does

1.Verify that the remote test/station is wired as shown in Fig. 27. Repair or replace loose or missing wiring.

2.Configure the sensor dirty test to activate the control- ler’s supervision relay. See “Changing Sensor Dirty Test Operation.”

Sensor’s Trouble LED is On, But the Controller’s Trouble LED is OFF

Remove JP1 on the controller.

PROTECTIVE DEVICES

Compressor Protection

Overcurrent

Each compressor has internal linebreak motor protection. Reset is automatic after compressor motor has cooled.

Overtemperature

Each compressor has an internal protector to protect it against excessively high discharge gas temperatures. Reset is automatic.

High Pressure Switch

Each system is provided with a high pressure switch mounted on the discharge line. The switch is stem-mounted and brazed into the discharge tube. Trip setting is 630 psig +/- 10 psig (4344 +/- 69 kPa) when hot. Reset is automatic at 505 psig (3482 kPa).

Low Pressure Switch

Each system is protected against a loss of charge and low evaporator coil loading condition by a low pressure switch located on the suction line near the compressor. The switch is stem-mounted. Trip setting is 54 psig +/- 5 psig (372 +/- 34 kPa). Reset is automatic at 117 +/- 5 psig (807 +/- 34 kPa).

Supply (Indoor) Fan Motor Protection

Disconnect and lockout power when servicing fan motor. The supply fan motor is equipped with an overcurrent protection device. The type of device depends on the motor size. (See Table 4.)

Table 4 – Supply Fan Motor Protection Devices

Motor Size	Overload Device	Reset
(bhp)
1.7	Internal Linebreak	Automatic
2.4	Internal Linebreak	Automatic
2.9	Thermik	Automatic
3.7	Thermik	Automatic
5.2	External	Manual
	(Circuit Breaker)

The Internal Linebreak type is an imbedded switch that senses both motor current and internal motor temperature. When this switch reaches its trip setpoint, the switch opens the power supply to the motor and the motor stops. Reset is automatic when the motor windings cool down.

The Thermik device is a snap-action overtemperature protection device that is imbedded in the motor windings. It is a pilot-circuit device that is wired into the unit’s 24-v control circuit. When this switch reaches its trip setpoint, it opens the 24-v control circuit and causes all unit operation to cease. This device resets automatically when the motor windings cool. Do not bypass this switch to correct trouble. Determine the cause and correct it.

The External motor overload device is a specially-calibrated circuit breaker that is UL recognized as a motor overload controller. It is an overcurrent device. When the motor current exceeds the circuit breaker setpoint, the device opens all motor power leads and the motor shuts down. Reset requires a manual reset at the overload switch. This device (designated IFCB) is located on the side of the supply fan housing, behind the fan access panel.

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