HEATED LANDING ZONE
CHAPTER 6: OPERATOR TROUBLESHOOTING
8
Symptom Possible
Cause
No computer display; no flow from
air tower
•
No
power
•
Circuit breaker out
•
Low
voltage
•
Bad
fuse
•
Bad
transformer
•
Hi-limit
out
No flow from air tower
•
Bad latching relay
After 20 minutes of operation
computer display shows PROB
•
RTD probe has failed.
Isolate failed component
by checking temperature of air and heater plate
with the temperature display keys on the
computer. The plate temperature should be
within ± 15°F of setpoint. The air heat should be
within ± 25°F of setpoint. If both temperatures are
good, the computer is likely bad.
After 20 minutes of operation
computer display shows HI
•
Plate heater, plate heater relay or RTD are faulty.
After 20 minutes of operation
computer display shows LO
•
Air heater, air heater relay or RTD are faulty
