If the rainfall measurement is inaccurate.
The rain gauge on the 5-in-1 sensor can be calibrated to improve accuracy by following the directions below.
5-in-1 sensor, display console, plastic cup, pin, screwdriver
- First, make sure the 5-in-1 sensor is perfectly level using the built-in bubble level.
- Place the display console 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 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 in 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 1.06"
If the rain gauge doesn't register close to 1.06" after the cup is empty of water, then you should make an equal adjustment to the two calibration screws on the bottom of the 5-in-1 sensor. Be sure to adjust both screws the same amount. Turning screws clockwise will increase the rainfall amount. Turning screw counter clockwise will decrease it.
- To adjust the rainfall reading by 2% turn both screws 1/8 of a turn.
- To adjust the rainfall reading by 4% turn both screws 1/4 of a turn.
- To adjust the rainfall reading by 8% turn both screws 1/2 of a turn.
There should be nearly an equal number of water drops (typically about 25 water drops) between bucket tips. If not, then adjust the calibration screws on the bottom of the 5-in-1 sensor until an equal number of water drops are tipping the buckets. Then, restart the calibration procedure.