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PREHEAT-X Technical Guide
Troubleshooting Alarms
Mechanical Failure:
•
Check relay outputs on the PREHEAT-X for 24 VAC
output.
•
Verify output voltage (VOUT and GND) to SCR or
PWM.
•
Verify that the Leaving Air Temperature Sensor(s)
is connected to AIN1 and/or AIN2 and GND on the
PREHEAT-X.
•
Verify Leaving Air Temperature Sensor probe(s) is
mounted correctly.
•
Remove AIN1 and AIN2 and GND wiring from the
PREHEAT-X and ohm out the sensor (this may indicate
open or failed wiring). Refer to chart in back of this
guide for readings.
Leaving Air Temperature Failure:
•
Verify that the Leaving Air Temperature sensor(s) is
connected to the AIN1 and/or AIN2 and GND on the
PREHEAT-X.
•
Remove AIN1 and AIN2 and GND wiring from the
PREHEAT-X and ohm out the sensor (this may indicate
open or failed wiring). Refer to chart in back of this
guide for readings.
Communications Loss:
•
Check COMM LED on PREHEAT-X.
•
Verify 24 VAC power to all interconnected controllers.
•
Verify connection between the PREHEAT-X and
associated controllers.
•
In Communications Mode (connected with a modular
cable), verify PREHEAT-X configuration on controller.
TROUBLESHOOTING
Alarms
