Hach 900 MAX - Manual (Page 131)

Appendix C
Page 129
8990apdx_tbl.fm Troubleshooting and Error Messages
Trouble Alarm Conditions, Causes, and Solutions
Trouble Condition Cause Solution
Low Main Battery Power supply voltage is less than 11 V dc. Change batteries.
Memory Battery Internal memory battery voltage is too low. Change memory batteries.
Low Slate Memory
Free slate memory is less than 20%. RAM
memory is almost full and will stop
recording soon. Download data from unit, halt and restart the
program or download data, halt, and change
data to wrap mode.
Slate Memory Full
No more slate memory. Unit is in slate memory
mode and cannot log any more data.
Download data and restart the program or
download data then change the
memory mode.
Modem Failure Unable to initialize modem PCB.
If the modem is enabled, the problem may be
found on the modem board and the board
may need to be replaced.
Missed Sample Sample cycle did not result in getting a sample. —
Purge Failure Sensor(s) still detecting liquid after a line purge. —
Jammed Distributor Distributor arm has jammed on an obstruction. Remove obstruction
Unable to Cool
Refrigeration system is unable to reduce
temperature in refrigeration compartment to
user defined setpoint.
—
Unable to Heat
Heater is unable to increase temperature in
refrigeration compartment to user defined
setpoint.
—
U-Sonic Echo Loss
The echo has been temporarily deflected by a
change in site conditions such as floating debris
or foam in the channel, wind, etc.
Check for excessive foam. Remove any debris
or build-up.
Xducer Ringing Transducer is operating within the deadband —
U-Sonic Failure
Transducer not plugged in. Cable damaged.
Transducer thermal sensor damaged. Check that the transducer is plugged in and
that there is no damage to the sensor.
RS485 Timed Out
Communication error between CPU and remote
ultrasonic module.
—
CPU is not communicating with the
Velocity board.
Wait a few minutes to see if it goes away, if it
continues it is an indication that there is a
problem with the CPU board.
Not receiving a good velocity reading.
If the logging interval is 1 or 2 minutes and
conditions are poor with the problem
continuing indefinitely, try increasing the
logging interval to allow more time to capture
the signal.