Clearing a Heater Fault Alarm
The Heater Fault alarm is a non-adjustable alarm. Its main purpose is to allow safe operation of the heater output
circuits. When a Heater Fault alarm occurs, the controller immediately switches off both heater outputs until the
alarm is cleared.
This alarm can occur under the following conditions:
• If a heater short circuit or an over-current condition is present at either heater output
NOTE:
The maximum allowable power limit for each heater is 25 W.
• If a thermocouple disconnect condition occurs. The controller monitors the ACT temperature reading versus the
SET temperature value for a one-minute period. If, within this one-minute period, the ACT and SET values are
not within 10 °C of one another, a Heater Fault Alarm is generated.
To Clear a Heater Fault Alarm:
1. If the Heater Fault alarm was caused by a short circuit or over-current condition, identify the cause and correct
the condition by removing the short circuit or removing the over-current condition.
2. If the Heater Fault alarm was caused by a thermocouple disconnect condition, inspect the system to ensure
that the heaters and thermocouples are thermally connected. In addition, perform an inspection of the wiring
and hardware integrity.
3. When the condition that caused the Heater Fault alarm is manually cleared, select ALARM for the affected
heater channel (on the HEATERS screen) and press ENTER to clear the alarm.
NOTES:
• If a heated valve requires more than 1 minute to reach a temperature that is within 10º C of its SET temperature,
gradually increase the SET temperature to allow the controller enough time to reach the desired temperature
setting. In a normal, room-temperature. In a normal, room-temperature environment, Nordson EFD valves rarely
require more than 1 minute to be within 10º C of SET temperature.
• The time allowed for a heated valve to reach a temperature that is within 10º C of its SET temperature can be
adjusted externally by changing the SET HEATER FAULT TIME (htft) command through an RS-232C computer
connection. Refer to “Connecting the Controller to a Computer” and Appendix B, “RS-232C Connection Technical
Information.”
Flashing Heater Fault
System Alarm
Clearing Alarms (continued)
ValveMate 9000 Controller
54
www.nordsonefd.com [email protected]
800-556-3484 Sales and service of Nordson EFD dispensing systems are available worldwide.