460I Electronic Demand System - Autotrol 460i Operation And Maintenance Manual

460i Electronic Demand System

The 460i electronic demand system is available as an
option on automatic controls for water conditioning
equipment. Retrofitting of existing water treatment
installations is easily accomplished, and the cost is
amortized over a short period of time by the home
owner in salt and water savings.
The two key components of the 460i electronic
demand system are the microprocessor, a miniature
computer located on the circuit board, and a water
meter located at the valve outlet. The flow of
conditioned water through the meter generates
electrical impulses that tell the computer the amount of
water being used.
Every day, at 2:00 a.m., the past seven days' water
usage is statistically averaged to anticipate the amount
of water to be used the next day. The computer then
determines if the water conditioner has enough
remaining capacity to supply the next day's needs. If
not, the unit will regenerate.
If the water usage pattern changes, the computer
automatically compensates for the change and
regenerates only when needed. This results in higher
operating efficiency and lower salt usage than a
conventional conditioner operating on a fixed
regeneration schedule.
Special Features
Memory Retention
During a power outage, all of the data in the
microprocessor's memory is stored in a special
electronic chip called NOVRAM, Nonvolatile Random
Access Memory. This data includes the time of day,
water usage amounts, and the number of days since
the last regeneration. The NOVRAM will maintain the
data in its memory. When power is restored, the
NOVRAM returns the data to the microprocessor and
operation resumes as if an outage never occurred.
The time of day will be late by the length of the power
outage. Most power outages are less than one minute
in duration. Therefore, it may be months or years before
the time display would require resetting. If an outage of
one or more hours occurs, the time of day should be
reset. No other reprogramming is necessary.
Self-Adjusting Reserve
"Reserve" refers to the amount of soft water that may
be needed for the next 24 hours. The microprocessor
calculates how much soft water was used and adjusts
the reserve capacity accordingly at the end of each day.
As a result, the reserve is kept at a minimum for
optimum economy. The reserve amount is calculated
by multiplying the average past seven days' usage
by 1.20. Regeneration decisions are based on the
calculated reserve.
In the event of unusually high water usage (twice or
more than the current daily average), the high usage
amount will be used as the reserve when the computer
performs its regeneration computation at 2:00 a.m.
This is done in anticipation of a second day of very high
usage.
High Water Usage
The 460i is programmed to react to a sudden increase
in water usage. If a day's usage is more than double the
current average, the computer anticipates that a
second day of high usage is likely to occur. The high
usage amount will be used as the reserve when the
460i performs its regeneration computation.
Low or No Water Usage
The 460i is programmed to recognize a day of very little
or no water usage as an abnormality. It will not use data
from such a day to compute the average usage. For
example, if the family is on vacation for a week, the
prior average will be maintained. When household
activity resumes, the 460i will operate as if the vacation
had not occurred.
Design Reliability
Solid-state electronics assure many years of trouble-
free performance. And, the metering system has only
one moving part, that is the rotating turbine that
measures water usage and creates magnetic pulses
that are continually counted by the microprocessor to
determine the need to regenerate.
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