h. Turn on the M820 controller.
i. Open the ow cell valves and wait for a few minutes for
the system to stabilize and get an accurate reading. Adjust
the Set Level if necessary.
3. Checking the ORP sensor
a. Place the sensor in a cup of tap water. The reading should
gradually drop down to 400mV.
b. Add a pinch of Dichlor, Trichlor or a drop of Liquid Chlorine
into the water. The reading should increase above 750mV.
4. Checking the pH sensor
a. Place the sensor in a cup of tap water.
b. Add a small amount of acid to the water and take a reading.
It should show a low number (probably 6.0).
c. Rinse the sensor, then place into a soluon that is higher
than 7.5pH. Verify that the reading is increasing.
M820 pH/Dual ORP Controller Owner’s Manual
27