35
Symptom Possible
Causes Corrective
Action
Display
reads "LO"
Wrong AC
adapter
Replace with
the correct AC
adapter.
Low AC line
voltage
Correct the AC
line voltage or
use batteries.
Dirty battery
contacts
Clean the
battery
contacts.
Display
reads
“CAL”
The Model
IAQ50 has
detected an
internal fault
Return to
factory for
service.
Display
reads
“OVER”
A parameter
value is too
high.
Use an
alternate
method to
make meas-
urement.
RTD became
unplugged
while reading
RTD tempera-
ture.
Plug in the
RTD
Temp.
initially
reads high
or low
Temperature
sensor is still
adjusting to
temperature
Allow
sufficient time
for the
temperature to
stabilize.