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NovaLynx Corporation 
 

 

255-704-B 

Page 14 

April 2021 

 

6.3

 

Water Level Management 

 
The logger can operate for long periods of time un-attended due to its very large memory capacity. 
However, other factors must be considered to ensure the evaporation station is operating properly. A 
regular maintenance period should be scheduled to inspect the evaporation pan, water replacement 
system, and operation of the logger and evaporation gauge. 
 
Evaporated water must be replaced. Ideally, the water level should be maintained from 7 to 8 inches 
deep (175 to 200 mm) in the evaporation pan. In practice, keeping the level between 5 and 8 inches 
deep (125 to 200 mm) is adequate. Do not overfill because the potentiometer may enter the dead band 
where the readings would be "floating", resulting in meaningless data. 
 
Water replacement can be accomplished by means of a NovaLynx 255-620-A Automatic Refill System, 
if a water source is available. Otherwise the station will need to be visited often enough to keep the 
water level within acceptable limits. 

Upload the data regularly and process the data. Water that is added either manally or automatically 
must be deducted from the evaporation totals. Water added by precipitation should also be deducted. 

7

 

MAINTENANCE 

 

At regular intervals, inspect the following: 

 

Check under the evaporation pan for leaks. 

 

Inspect the pipe between the pan and the analog evaporation gauge for leaks. 

 

Make sure the automatic refill system shuts off completely between refills. 

 

If the optional offset calibration (Section 5.5) was performed when the logger was installed, 
compare the reading on the logger with the actual water level (

use a measuring stick

). 

 

Note:

 If the offset calibration was not done the measurements will not agree because the 

generic calibration does not include an offset for the amount of water required to cause the 
float to lift off the bottom of the pan. 

 

Read the logger memory using a computer. Check the data to ensure the logger is recording 
data properly. 

 

From the HOBOware icon menu, select "Device status" and verify the battery is good and the 
memory is not too full. Replace the two AAA batteries if needed (Section 8). 

 

Be sure to "Start" the logger before disconnecting. 

 

Disconnect the USB cable. 

 

Install the logger in the enclosure.  

 

Make sure the sensor cable on the bottom of the logger is plugged in all the way and the 
display is showing the correct water level.  

 

Verify the logger is LOGGING and the display updates every 15 seconds. 

Summary of Contents for 255-704-B

Page 1: ...04 B UM 20210419 255 704 B User Manual 255 704 B Evaporation Logger 255 704 B Evaporation Logger with 255 100 Analog Output Evaporation Gauge Phone 530 823 7185 Email nova novalynx com Website www nov...

Page 2: ...items If packing facilities are not available take the equipment to the nearest Post Office UPS or other freight service and obtain assistance with the packaging Please write the RA on the outside of...

Page 3: ...tions 5 5 2 Float and Chain Installation 6 5 3 Software Installation 6 5 4 Logger Settings 8 5 5 Offset Calibration optional 11 5 6 Field Calibration optional 11 6 OPERATION 12 6 1 Start Logging 12 6...

Page 4: ...the current water level in the evaporation pan along with logging status battery status and memory consumption The logger stores up to 1 9 million measurements with 16 bit resolution The logger is pro...

Page 5: ...is straightforward The enclosure is fitted with a large band clamp which must be opened and passed around the body of the evaporation gauge photo Adjust the height so that the logger does not interfer...

Page 6: ...o clock position 30 degrees to left 3 Lift the chain until all the slack is taken up but the float is still resting on the bottom of the gauge Drape the chain over the sprocket so that the float is o...

Page 7: ...to the computer 4 Look at the status ribbon at the bottom of the HOBOware program window below At first the status will indicate No devices connected Within a minute the status should update and show...

Page 8: ...Logger has been pre programmed to read Channel 1 as water level in the evaporation pan The logger will be programmed either in inches or millimeters depending on the order specification The example be...

Page 9: ...ant window will open Please verify the settings on your logger NOTE The generic calibration shown above does not take into account the amount of water required to raise the float off the bottom of the...

Page 10: ...dow 11 Click the Device status icon to open the Status window below Note the battery level and memory used to ensure there is enough power and memory available for your next logging session 12 Set the...

Page 11: ...er s reading at that level 1 Measure the water depth and calculate the offset Example 8 00 Measured Depth 6 30 Logger Reading 1 7 Offset 2 Add the offset to the generic calibration values Value 1 Scal...

Page 12: ...ose the Status window 4 Open the Launch Logger window and navigate to the Linear Scaling Assistant window Section 5 4 Enter your measurements in place of the generic parameters 5 Click Update to save...

Page 13: ...file location and filename then click Save Once the file is saved the Plot Setup screen will open Select the elements you want to display in graphical and tabular form then click Plot LEFT Plot Setup...

Page 14: ...ust be deducted from the evaporation totals Water added by precipitation should also be deducted 7 MAINTENANCE At regular intervals inspect the following Check under the evaporation pan for leaks Insp...

Page 15: ...it back into place The two AAA 1 5V batteries should provide you with 7 to 9 months of continuous use Note A desiccant pack may be inside the logger box It can be replaced or retreated as needed 9 TEM...

Page 16: ...eight Drape the counterweight and chain over the outside of the gauge Do not attempt to remove the float 3 Rotate the sprocket by hand to verify that it turns freely 360 without binding It should spin...

Page 17: ...the sprocket may have slipped on the shaft and be out of position If the readings on the display are progressively worse the farther the sprocket is turned the potentiometer may be out of specificatio...

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