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Bradford White
Page 26
Copper Brute II
Page 27
6.3.4 Boiler Maximum (BOIL MAX)
The boiler maximum (BOIL MAX) is the highest
water temperature that the control is allowed to use
as a target temperature. If the control does target
BOIL MAX, and the heater outlet sensor is near the
BOIL MAX temperature, the MAX segment turns
on in the LCD while the target, inlet, outlet or supply
temperature is viewed (see Figure 14).
a set point demand. During WWSD, if the pump has
not operated at least once every 70 hours, the control
energizes the terminals for 10 seconds. This minimizes
the possibility of the pump seizing during a long
period of inactivity. During External Heater Operation
(mode 6), the pump contact closes whenever there is a
heat demand.
Boiler Purge (PUMP DLY) – After a demand
is satised, the control continues to operate the pump
for a period of time. The length of time that the pump
continues to run is based on the pump delay setting.
Once the last stage of the control turns off, the control
keeps the pump contacts energized for the time
selected (between 0 and 10 minutes). When OFF is
selected, there is no purging. When ON is selected,
pump operation is continuous. Also, during outdoor
reset, with the pump delay set to ON, the pump
continues to run even during Warm Weather Shut
Down.
6.3.7 Set point Operation
When either mode 1 or 2 is selected, the control
controls the water temperature based on a xed set
point. The set point temperature is set using the BOIL
TARGET item in the Adjust menu.
Heat Demand – For “heat demand” to exist,
there must be continuity between the Com D (common
demand) and the Ht D (heat demand) terminals. The
heater ships with a jumper between these terminals.
The control also evaluates the sensor(s) installed
in the system, including the outlet sensor provided
on the heater when using mode 1. When the control
senses continuity between Com D and Ht D terminals,
and that the sensor reading is below the target
temperature, the control will activate the Dem segment
in the display.
The control energizes the pump (on pump
mounted heater) and energizes the Pmp Pmp terminals.
The heater pump segment is turned on in the display.
The control then operates the stages to maintain the set
point temperature.
6.3.8 Dedicated Domestic Hot Water
When mode 3 is selected, the control provides
dedicated domestic hot water operation.
Internal DHW Demand – A sensor is required
to be connected on the SC2 and Sup/S terminals.
An internal demand for DHW is generated when the
temperature demand for DHW sensor drops of the
tank differential setting below the desired DHW tank
temperature. The TANK TARGET setting is used to
set the desired DHW tank temperature.
Once an internal demand is generated, the
Dem segment turns on in the LCD. The control then
closes the Pmp Pmp contact, which starts the pump
and the control turns on the heater pump segment in
the display. The control then operates the stages to
maintain the programmed heater target temperature at
the heater outlet sensor.
Figure 14. Temperature Control Min & Max Graph.
6.3.5 Boiler Target Temperature
The target temperature is determined from
the mode of operation. The control displays the
temperature that is currently trying to maintain at
the operating sensor as BOIL TARGET in the View
menu. The operating sensor for modes 1, 3 and 4 is the
outlet sensor (on the heater). The operating sensor for
modes 2 and 5 is the supply sensor (in the system or
primary loop). If the control does not presently have
a requirement for heat, it displays “- - -” in the LCD.
There is no target temperature generated in mode 6
(external controller mode).
6.3.6 Pump Operation
The pump terminals (Pmp Pmp) are energized
with 24 VAC to control a eld supplied pump
contactor. During set point operation (modes 1 and 2),
the terminals are energized whenever there is a heat
demand. During dedicated DHW operation (mode
3), the terminals are energized whenever there is an
internal heat demand. During outdoor reset (modes 4
and 5), the terminals are energized whenever there is
either a heat demand and the control is not in Warm
Weather Shut Down (WWSD), or whenever there is