Resetting Refill Threshold - Bunn Axiom Series Technical Training Manual

Setting the Refill Threshold
The refill setting in programming is a conductivity based system. It is a reading that is generated by the liquid level
probe and the conductivity of the water in the tank has a total range of 0 - 255 (this can be viewed on the Refill pro-
gram screen). The lower the reading, the more conductance is being sensed. Conversely, the higher the reading, the
less conductance. Theoretically it would read 0 when the probe touches the water, and 255 when it is not touching
the water. However, due to water conditions and conditions in the tank, it may not have these exact readings.
The programmable portion of the system is the "switching point" (or threshold). This is typically set to 155 (your
default value). When the probe reading is less than this programmed number, it will be viewed as not requiring water
from the refill system. When it is the number or greater, it will be viewed as needing water.
If this threshold is causing problems, there's a simple way to determine the optimum switching point.
Step 1: With water known to be touching the liquid level probe, record the probe reading that is present on the Refill
program screen (it will show the programmed threshold and the actual reading, here we want the actual
reading).
Step 2: Now create a situation where it is known the water is not touching the probe (can raise the probe out of the
tank). Record the probe reading.
Step 3: With the 2 readings, set the programmed threshold to be exactly half-way
between the 2 numbers.
Actual Reading Default Reading
XXX REFILL 155
(-) DONE (+)
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