Hach 900 MAX Trouble Alarm Conditions, Causes, and Solutions, Appendix C, Trouble Condition, Page

Appendix C

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.
	Free slate memory is less than 20%. RAM	Download data from unit, halt and restart the
Low Slate Memory	memory is almost full and will stop	program or download data, halt, and change
	recording soon.	data to wrap mode.
	No more slate memory. Unit is in slate memory	Download data and restart the program or
Slate Memory Full		download data then change the
	mode and cannot log any more data.
		memory mode.
		If the modem is enabled, the problem may be
Modem Failure	Unable to initialize modem PCB.	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
	Refrigeration system is unable to reduce
Unable to Cool	temperature in refrigeration compartment to	—
	user defined setpoint.
	Heater is unable to increase temperature in
Unable to Heat	refrigeration compartment to user defined	—
	setpoint.
	The echo has been temporarily deflected by a	Check for excessive foam. Remove any debris
U-Sonic Echo Loss	change in site conditions such as floating debris
		or build-up.
	or foam in the channel, wind, etc.
Xducer Ringing	Transducer is operating within the deadband	—
U-Sonic Failure	Transducer not plugged in. Cable damaged.	Check that the transducer is plugged in and
	Transducer thermal sensor damaged.	that there is no damage to the sensor.
	Communication error between CPU and remote	—
	ultrasonic module.
	CPU is not communicating with the	Wait a few minutes to see if it goes away, if it
		continues it is an indication that there is a
	Velocity board.
		problem with the CPU board.
RS485 Timed Out
		If the logging interval is 1 or 2 minutes and
		conditions are poor with the problem
	Not receiving a good velocity reading.	continuing indefinitely, try increasing the
		logging interval to allow more time to capture
		the signal.

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8990apdx_tbl.fm	Troubleshooting and Error Messages