Table 21 Ð PARABLADE Economizer Troubleshooting
PROBLEM | CAUSE |
| REMEDY |
Damper does not | Evaporator fan not on. | Check wiring between G on connection board and indoor (evaporator) fan | |
open. |
| contactor. | |
| No power to economizer | 1. | Disconnect power at TR and TR1. Disconnect jumper across P and P1. |
| motor. | 2. | Connect jumper across TR and 1. |
|
| 3. | Connect jumper across T1 and T. |
|
| 4. | If connected, remove enthalpy sensor from terminals SO and +. |
|
| 5. | Apply power (24 vac) to terminals TR and TR1. The LED should be off and |
|
|
| the damper should be in the closed position. |
|
| 6. | Disconnect the |
|
|
| The LED should light up and the motor should drive towards open. If this |
|
|
| does not happen, replace the economizer control module. |
| Economizer motor failure. | If the indoor (evaporator) 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 oper- | |
|
| ating, replace the motor. | |
Economizer op- | Economizer control module | 1. | To simulate high or low enthalpy, reconnect the |
eration limited to | failure. |
| resistor across terminals SR and +. |
minimum position. |
| 2. | Connect 1.2 Kohm checkout resistor across terminals SO and +. Turn the |
|
|
| enthalpy set point to ``A.'' The LED should turn on, indicating low enthalpy. |
|
|
| The motor should drive towards open. If LED does not light, replace module. |
|
|
| If motor does not drive open, check motor operation. |
|
| 3. | Turn the enthalpy set point to ``D.'' The LED should turn off, indicating high |
|
|
| enthalpy. The motor should drive towards closed. If these actions do not oc- |
|
|
| cur, replace module. |
|
| 4. | Disconnect 1.2 Kohm checkout resistor before resuming operation. |
Damper does not | No power to economizer. | 1. | Disconnect power at TR and TR1. Disconnect jumper across P and P1. |
close. |
| 2. | Connect jumper across TR and 1. |
|
| 3. | Connect jumper across T1 and T. |
|
| 4. | If connected, remove enthalpy sensor from terminals SO and +. Factory- |
|
| 5. | installed 620 ohm resistor should be connected to terminals SR and +. |
|
| Apply power (24 vac) to terminals TR and TR1. The LED should be off and | |
|
|
| the damper should be in the closed position. |
|
| 6. | Disconnect the |
|
|
| The LED should light up and the motor should drive towards open. If this |
|
|
| does not happen, replace the economizer control module. |
| Spring return failure. | 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. | |
| Economizer motor failure. | 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, re- | |
|
| place the motor. | |
Damper does not | Sensor incorrectly wired or | To verify sensor operation, reconnect the + lead of the outdoor enthalpy sensor | |
open or close | bad. | to the + terminal of the economizer control module. Connect a DC milliammeter | |
according to |
| between terminals SO of the economizer control module and terminals S of the | |
enthalpy readings. |
| enthalpy sensor. The milliammeter should indicate between 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. | |
LED Ð |
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| |
