The following calibration procedure can be used if the rainfall measurements produced by the AcuRite AcuRite Atlas® (7-in-1) sensor are inaccurate or incorrect. This procedure does not need to be performed upon receiving the AcuRite Atlas® (7-in-1) sensor, it is calibrated during the manufacturing process.
To calibrate the rain gauge on the AcuRite Atlas® (7-in-1) sensor:
- First, make sure the AcuRite Atlas® (7-in-1) sensor is perfectly level using the built-in bubble level.
- Place the display unit close by so you can monitor it during the calibration process.
- Make a pinhole in the bottom of a plastic cup. Hold the cup over the rain gauge and fill it with exactly 1 cup (8 oz.) of water, allowing the water to slowly drip into the rain gauge. You should hear the internal buckets tip and see the water drain through the rain gauge.
- A few seconds after each bucket tip, the display console will display rainfall as approximately 0.01" or more increments.
- The cup of water should take more than 20 minutes to empty; a quicker period will result in an inaccurate calibration. (We’re trying to simulate a normal steady rainfall.) When the cup is completely empty of water, the display console should register 0.61"
NOTE: We recommend performing this procedure multiple times BEFORE making any adjustments to the calibration screws to ensure adjustment is needed.
If the rain gauge doesn't register close to 0.61" after the cup is empty of water, then you should make an equal adjustment to the two calibration screws beneath the tipping lever. Be sure to adjust both screws the same amount. Turning screws clockwise will decrease the rainfall amount. Turning screws counter-clockwise will increase the rainfall amount.
To adjust the rainfall reading by 2.5% turn both screws 1/4 of a turn.
To adjust the rainfall reading by 5% turn both screws 1/2 of a turn.
To adjust the rainfall reading by 7.5% turn both screws 3/4 of a turn.
To adjust the rainfall reading by 10% turn both screws 1 full turn.
- There should be nearly an equal number of water drops between bucket tips. If not, then adjust the calibration screws beneath the tipping lever until an equal number of water drops are tipping the buckets. Then, restart the calibration procedure.
- If you don't hear the buckets tipping and see water dripping alternately out of each drain, there may be an issue with the rain gauge or its adjustment.
Here is a helpful video for calibrating the Atlas sensor:
If you have accidentally removed the calibration screws or adjusted them unevenly, the following procedure approximately resets the screws to the Factory Default.
- Tighten the calibration screws fully
- Unscrew the shorter one 2 1/2 turns and the taller one only 1 turn, as shown in the following image.
- Clear today's rain totals or note the current rainfall reading.
- Rock the sensor back and forth until you hear 10 clicks- you may need to open up the sensor and tip the cups back and forth manually.
- In a minute or so, the rain total on the display should be .10 inches (every click/tip should register .01)
- *To increase rainfall-turn screws counter-clockwise
- *To decrease rainfall- turn screws clockwise