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Bradford White
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Copper Brute II
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Minimum Off Time (MIN OFF) – The
minimum off time is the minimum amount time that a
stage must be off before it is allowed to turn on. Once
a stage turns off, it cannot turn on until a minimum
off time elapses. The minimum off time is adjustable
through the MIN OFF setting in the Adjust menu.
Proportional & Integral & Derivative (PID)
– PID staging allows the control to determine when
the next stage is required to turn on. The control
automatically determines the settings that are manually
selected in proportional staging mode. After each stage
is turned on in the ring sequence, the control waits a
minimum amount of time before turning on the next
stage. After the minimum time delay between stages
has expired, the control examines the control error to
determine when the next stage is to re. The control
error is determined using PID logic.
Proportional compares the actual operating
sensor temperature to the heater target temperature.
The colder the temperature, the sooner the next stage
is turned on.
Integral compares the actual operating sensor
temperature to the heater target temperature over a
period of time.
Derivative determines how fast or slow the
operating sensor temperature is changing. If the
temperature is increasing slowly, the next stage is
turned on sooner. If the temperature is increasing
quickly, the next stage is turned on later, if at all.
Boiler Mass (BOIL MASS) – The boiler mass
setting allows the installer to adjust the control to the
thermal mass of different types of heat sources used.
The boiler mass setting automatically determines the
interstage differential, interstage delay on, interstage
delay off, minimum on time and minimum off time of
the stages when PID staging is used. A higher thermal
mass setting provides slower staging, while a lower
thermal mass setting provides faster staging. Copper
Brute II water heaters are low-mass appliances, and
therefore, should be used with the lower thermal mass
setting. Set BOIL MASS to “1”.
6.3.3 Boiler Minimum (BOIL MIN)
The minimum boiler setting (BOIL MIN) is the
lowest water temperature that the control is allowed
to use as a target temperature. During mild conditions,
if the control calculates a target temperature that is
below this setting, the target temperature is adjusted to
at least the minimum setting. During this condition, if
the unit is operating, the MIN segment turns on in the
LCD while the target temperature or operating sensor
temperature is viewed. For Copper Brute II units, this
must be set no lower than 120°F (49°C) to protect the
unit from condensing on the heat exchanger (see Figure
14).
6.3.1 Differential
Differential has an abbreviated name of DIFF. An
on/off heat source must be operated with a differential
in order to prevent short cycling. The differential
is divided around the boiler target temperature (see
Figure 13). The rst stage contact will close when the
water temperature at the operating sensor is one-half of
the differential setting below the target temperature. It
will open when the water temperature at the operating
sensor is one-half of the differential setting above the
target temperature. The remaining stages will operate
sequentially, based on the staging mode selected.
6.3.2 Staging Mode
The Copper Brute II 500 and 750 control
operates two stages. The Copper Brute II 1000 control
operates three stages. The Copper Brute II control for
models 1250-2000 operates four stages. The method
of staging used by the control is either P (proportional)
or PID (proportional & integral & derivative), and
is selected using the STGMODE item in the Adjust
menu.
Proportional (P) – Proportional staging, also
known as step staging, is based on manually adjusted
settings which determine when the next stage is
required to turn on. These manual settings are based
on temperature and time. The interstage differential
sets the temperature drop at which the next stage turns
on. However, in order for a stage to re, the interstage
delay on and minimum off times must rst elapse.
Interstage Differential (STG DIFF) – The
interstage differential is the temperature drop at which
the next stage will turn on. Once a stage turns on, the
next stage cannot turn on until the temperature drops
the interstage differential below the temperature at
which the previous stage turned on. The interstage
differential is adjustable through the STG DIFF setting
in the Adjust menu. See Figure 13.
Interstage Delay On (ON DLY) – The
interstage delay on is the amount of time that must
elapse before turning on the next stage. Once a stage
turns on, the next stage cannot turn on until the
interstage delay on time elapses. The interstage delay
on is adjustable through the ON DLY setting in the
Adjust menu.
Interstage Delay Off (OFF DLY) – The
interstage delay off is the amount of time that must
elapse before turning off the next stage. Once a stage
turns off, the next stage cannot turn off until the
interstage delay off time elapses. The interstage delay
off is adjustable through the OFF DLY setting in the
Adjust menu.
Minimum On Time (MIN ON) – The minimum
on time is the minimum amount time that a stage must
be on before it is allowed to turn off. Once a stage
turns on, it cannot turn off until a minimum on time
elapses. The minimum on time is adjustable through
the MIN ON setting in the Adjust menu.