Troubleshooting - Bryant 581B Installation & Service Instructions Manual

PROBLEM
Damper does not open. Evaporator fan not on.
No power to economizer motor.
Economizer motor failure.
Economizer operation Economizer control module
limited to minimum failure.
position.
Damper does not close. No power to economizer.
Return spring failure.
Economizer motor failure.
Damper does not open Sensor incorrectly wired or bad.
or close according to
enthalpy readings.
Table 22 — PARABLADE Economizer Troubleshooting
CAUSE
Check wiring between G on connection board and indoor fan contactor.
1. Disconnect power at TR and TR1. Disconnect jumper across P and P1.
2. Connect jumper across TR and 1.
3. Connect jumper across T1 and T.
4. If connected, remove enthalpy sensor from terminals S
5. Apply power (24 vac) to terminals TR and TR1. The LED should be off
6. Disconnect the factory-installed 620 ohm resistor from terminals S
If the indoor fan and economizer motor are energized, verify that there is a
minimum of 24 vac at terminals TR and TR1. If the motor is not operating,
replace the motor.
1. To simulate high or low enthalpy, reconnect the factory-installed 620 ohm
2. Connect 1.2 Kohm checkout resistor across terminals S
3. Turn the enthalpy set point to ''D.'' The LED should turn off, indicating
4. Disconnection 1.2 Kohm checkout resistor before resuming operation.
1. Disconnect power at TR and TR1. Disconnect jumper across P and P1.
2. Connect jumper across TR and 1.
3. Connect jumper across T1 and T.
4. If connected, remove enthalpy sensor from terminals S
5. Apply power (24 Vac) to terminals TR and TR1. The LED should be off
6. Disconnect the factory-installed 620 ohm resistor from terminals S
If power to unit is off and damper does not close, check for a bound linkage.
If linkage is not bound, then internal spring may be broken. Replace
actuator.
If the economizer control module is functioning properly, verify that there is a
minimum of 24 Vac at terminals TR and TR1. If the motor is not operating,
replace the motor.
To verify sensor operation, reconnect the + lead of the outdoor enthalpy sen-
sor to the + terminal of the economizer control module. Connect a DC mil-
liammeter between terminals S
terminals S of the enthalpy sensor. The milliammeter should indicate be-
tween 3 and 25 mA if the sensor is operating properly. If the milliammeter
indicates 0, the sensor may be wired backwards. If any other readings are
shown, replace the sensor.
—36—
installed 620 ohm resistor should be connected to terminals S
and the damper should be in the closed position.
+. The LED should light up and the motor should drive towards open. If
this does not happen, replace the economizer control module.
resistor across terminals S and +.
R
enthalpy set point to ''A.'' The LED should turn on, indicating low en-
thalpy. The motor should drive towards open. If LED does not light, re-
place module. If motor does not drive open, check motor operation.
high enthalpy. The motor should drive towards closed. If these actions do
not occur, replace module.
installed 620 ohm resistor should be connected to terminals S
and the damper should be in the closed position.
+. The LED should light up and the motor should drive towards open. If
this does not happen, replace the economizer control module.
of the economizer control module and
O
REMEDY
and +. Factory-
0
and +. Turn the
O
and +. Factory-
O
and +.
R
and
R
and +.
R
and
R