SOLID STATE ECONOMIZER SYSTEM
63-2484—1
18
Table 7. Troubleshooting modulating economizer—outdoor enthalpy below setpoint.
NOTES:
1. Standard economizer position based on enthalpy control set on the A setting and 50 percent relative humidity.
2. Closed position is either the minimum position or fully closed, depending on the job setting.
3. Opening/closing is dependent on the mixed air temperature.
Condition on Logic Module Should Be Conditions Not Met
1. Red LED lighted. 1. Jumper terminals {SO} and {+}. If the LED lights, the module is okay, see
Note 2. Check wiring to enthalpy control.
2. 24 Vac to terminals {TR} and {TR1}. 2. Check the wiring from [G] and [C] on the unit low voltage terminal strip.
{TR} and {TR1} power the actuator.
3. 24 Vac to terminals {1} and {TR1}. 3. Verify there is a call for cooling from the thermostat. Without a call for
cooling, the motor can not be in the economizer mode.
4. No continuity on terminals {1} and {2}. 4. If there is continuity from terminals {1} and {2}, the red LED should not be
lighted. If there is continuity and the LED glows, the module is defective.
5. Continuity on terminals {3} and {5}. 5. If there is continuity on terminals {3} and {5}, the internal switch is correctly
energized. Damper motor should be in a modulating mode.
6. Motor does not operate with all above
conditions met.
6. Jumper the mixed air sensor terminals {T} and {T1}. If the motor begins to
operate, check the wiring to the sensor. If correct, the temperature is below
the sensor setpoint or it is defective. If the motor does not operate, and the
wiring is correct and the temperature is above the sensor setpoint, the
motor is bad.
Second Stage
7. 24 Vac to terminals {3} and {TR1}. 7. Verify that you have a two-stage thermostat. Check for a call for a second
stage cooling. If 24 Vac is not on terminals {3} and {TR1}, check wiring
from terminal Y2 on the thermostat to the module.
8. 24 Vac to terminals {5} and {TR1}. 8. If terminals {5} and {TR1} do not have 24 Vac, the intermal switch is not in
the correct position, assuming that terminals {3} and {TR1} do have
24 Vac. The module is defective.
9. Compressor does not operate with
second stage conditions met.
9. If all other functions are correct, check the wiring from terminal {5} to Y2 on
the unit low voltage terminal board.
{ } Terminals on the logic module.
[ ] Low voltage input from unit or thermostat.
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