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RESETTING ALARM AND TROUBLE
TRIPS:
Manual reset is required to restore smoke detector systems to
Normal operation. For installations using two sensors, the duct
smoke detector does not differentiate which sensor signals an
alarm or trouble condition. Check each sensor's LED for
Alarm or Trouble status. Clear the condition that has generated
the trip at this sensor. Then reset the sensor by pressing and
holding the reset button (on the side) for 2 seconds. Verify that
the sensor's Alarm and Trouble LEDs are now off. At the con-
troller, clear its Alarm or Trouble state by pressing and holding
the manual reset button (on the front cover) for 2 seconds. Ver-
ify that the controller's Alarm and Trouble LEDs are now off.
Replace all panels.
Troubleshooting
CONTROLLER'S TROUBLE LED IS ON
1.
Check the Trouble LED on each sensor connected to the
controller. If a sensor's Trouble LED is on, determine the
cause and make the necessary repairs.
2.
Check the wiring between the sensor and the controller. If
wiring is loose or missing, repair or replace as required.
CONTROLLER'S TROUBLE LED IS FLASHING
1.
One or both of the sensors is 100% dirty.
2.
Determine which Dirty LED is flashing, then clean that sen-
sor assembly as described in the detector cleaning section.
SENSOR'S TROUBLE LED IS ON
1.
Check the sensor's Dirty LED. If it is flashing, the sensor
is dirty and must be cleaned.
2.
Check the sensor's cover. If it is loose or missing, secure
the cover to the sensor housing.
3.
Replace sensor assembly.
SENSOR'S POWER LED IS OFF
1.
Check the controller's Power LED. If it is off, determine
why the controller does not have power and make the nec-
essary repairs.
2.
Check the wiring between the sensor and the controller. If
wiring is loose or missing, repair or replace as required.
CONTROLLER'S POWER LED IS OFF
1.
Make sure the circuit supplying power to the controller is
operational. If not, ensure 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 repair
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. 36. Repair or replace loose or missing wiring.
2.
Configure the sensor dirty test to activate the controller's
supervision relay. See "Changing sensor dirty test operation."
SENSOR'S TROUBLE LED IS ON, BUT THE CONTROL-
LER'S TROUBLE LED IS OFF
Remove JP1 on the controller.
CONDITION
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 evap-
orator 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
PERSONAL INJURY HAZARD
Failure to follow this caution can result in personal injury.
Disconnect all electrical power when servicing the fan mo-
tor. Apply appropriate lockout/tag-out procedures.
Motors with 2.9 and 3.7 bhp are equipped with an overtem-
perature or protection device. The type of device depends on
the motor size. See Table 8.
The High Static option supply fan motor is equipped with a pi-
lot-circuit Thermik
protection device. This device resets automatically. Do not by-
pass this switch to correct trouble. Determine the cause and
correct it.
The Thermik device is a snap-action overtemperature protec-
tion device that is embedded in the motor windings. The Ther-
mik device can be identified by two blue wires extending out
of the motor control box. 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 automati-
cally when the motor windings cool. Do not bypass this switch
to correct trouble. Determine the cause and correct it.
The External Overload Breaker is an overcurrent device used
on motors with a horsepower rating of 4.7 hp or greater. This is
a specially-calibrated circuit breaker that is UL recognized as a
motor overload controller. When the current to the motor ex-
ceeds the circuit breaker setpoint, the device opens all motor
power leads to the motor shutting the motor down. Reset re-
quires a manual reset at the overload switch. This device (des-
ignated IFCB) is located on the side of the supply fan housing,
behind the fan access panel. The Must Hold and Must Trip val-
ues are listed on the side of the External Overload Breaker.
TROUBLESHOOTING SUPPLY FAN MOTOR OVER-
LOAD TRIPS
The supply fan used in 48HC units is a forward-curved centrif-
ugal wheel. At a constant wheel speed, this wheel has a charac-
teristic that causes the fan shaft load to DECREASE when the
1. Thermik is a trademark of Thermik Geratebau GmbH.
32
PROTECTIVE DEVICES
CAUTION
1
combination overtemperature/overcurrent
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Troubleshooting
