Page 44 | BRADFORD WHITE CORP. |
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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.
6.4.7 Setpoint Operation
When either mode 1 or 2 is selected, the control controls the water temperature based on a fixed setpoint. The setpoint 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 Copper Brute II 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 boiler 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 boilers) and energizes the Pmp Pmp terminals. The boiler pump segment is turned on in the display. The control then operates the stages to maintain the setpoint temperature.
6.4.8Dedicated 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 ½ 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 boiler pump segment in the display. The control then operates the stages to maintain the programmed boiler target temperature at the boiler outlet sensor.
The boiler target temperature is set using the BOIL TARGET item in the Adjust menu. NOTE: External demand is not required in this mode of operation.
Tank Differential – A differential setting that operates ½ above and below the TANK TARGET is selectable using the TANK DIFF item in the Adjust menu.
6.4.9 Outdoor Reset Operation
When either mode 4 or 5 is selected, the control
uses outdoor reset to control the water temperature. Outdoor reset adjusts the target temperature based on the outdoor air temperature and reset ratio. The reset ratio is determined from the Boiler Start, Boiler Design, Outdoor Start and Outdoor Design settings.
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 Copper Brute II ships with a jumper between these terminals.
The control also evaluates the sensor(s) installed in the system. If the control is not in warm weather shutdown (WWSD), and the sensor(s) are below the target temperature, the Dem segment is turned on
in the display. The control energizes the pump (on pump mounted boilers) and energizes the
Boiler Start (BOIL START) – The BOIL START temperature is the theoretical boiler supply water temperature that the heating system requires when the outdoor air temperature equals the OUTDR START temperature setting. The BOIL START is typically set to the desired building temperature (see Figure 30).
Outdoor Start (OUTDR START) – The OUTDR START temperature is the outdoor air temperature at which the control provides the BOIL START water temperature to the system. The OUTDR START is typically set to the desired building temperature.
Outdoor Design (OUTDR DSGN) – The OUTDR DSGN is the outdoor air temperature that is