Bradford-White Corp BWCV warranty Internet Version for Reference Only, Bradford White

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6.3.9 Outdoor Reset Operation

Internet Version for Reference Only

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Bradford White

 

 

 

 

The heater 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 1⁄2 above and below the TANK TARGET is selectable using the TANK DIFF item in the Adjust menu.

6.3.9 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 heater 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 Pmp-Pmp terminals, and the heater pump segment is turned on in the display. The control then operates the stages to maintain the set point temperature.

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 15).

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 the typical coldest temperature of the year where the building is located. This temperature is used when doing heat loss calculations for the building.

Boiler Design (BOIL DSGN) – The BOIL DSGN temperature is the water temperature required to heat the boiler zones when the outdoor air is as cold as the OUTDR DSGN temperature.

Warm Weather Shut Down (WWSD) – When the outdoor air temperature rises above the WWSD setting, the control turns on the WWSD segment

in the display. When the control is in WWSD, the Dem segment is displayed if there is a heat demand.

Figure 15. Temperature Control Outdoor Start Graph.

However, the control does not operate the heating system to satisfy this demand. The control does respond to a set point demand and operates as described in the Reset Override section (next).

Reset Override (SET POINT DEMAND)

–This is used when override of the outdoor reset curve is needed, such as when an indirect water heater is served by the heating system. A set point demand is required whenever heat is required for the set point load. The set point demand overrides the reset water temperature. The control turns on the Setp Dem pointer in the display. The control energizes the pump (on pump-mounted heaters), energizes the Pmp-Pmp terminals, and turns on the heater pump segment in the display. The control then operates the heater stages to maintain the programmed target temperature. The reset override operation is not affected by WWSD.

6.3.10 External Heater Operation

When mode 6 is selected, the control allows for an external control to operate the heater’s stages. In this mode, the control operates the pump in order to provide purging and exercising. The staging operation is provided by an external device such as an Energy Management System (EMS) or External Staging Control.

Heat Demand – A heat demand is generated when stage one is wired properly, and the external control closes the contacts on the stage one terminals (1C-1NO), calling the heater for heat. The heater is shipped with a jumper between the Com D and Ht D terminals, and this jumper must remain in place when and external control is providing the heat demand

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Contents Internet Version for Reference Only Installation and Operation Instructions forInstallation and Operation Instructions Copper BruteTABLE OF CONTENTS SECTION 7. MaintenanceSECTION 8. Trouble Shooting SECTION 9. Wiring Diagrams1.1 Introduction SECTION General Information1.2 Model Identification 1.3 Warranty 1.4 Dimensions1.5 Locating the Appliance Figure 1. Dimensional Data SECTION Venting and Combustion Air 1.6 Locating Pump-Mounted Water Heater with Respect to Storage TanksFrom Outside Wall 2.1 Combustion Air2.1.2 Intake Combustion Air 2.2 Venting 2.2.1 Vent Categories2.2.2 Category I Vent 2.2.3 Common Venting SystemsFigure 3. Combustion Air and Vent Through Side Wall 2.3 Locating Vent & Combustion Air Terminals Important Note Massachusetts Code Requirement2.3.1 Side Wall Vent Terminal 2.3.2 Side Wall Combustion Air Terminal2.4 Common Vent Test 2.5 Vent Terminals for Outdoor Units2.3.3 Vertical Vent Terminal 2.3.4 Vertical Combustion Air TerminalSECTION Gas Supply and Piping 3.1 Gas Supply and PipingSECTION Water Connections Copper Brute II Water Heater 4.1 Water System Piping Water Heater4.2 Hot Water Supply Piping - Water Heater 4.3 Water Flow Requirements - Water HeaterTable 8. Water Flow Requirements Figure 4. Water Heater Piping - One Heater, One TankFigure 5. Water Heater Piping - Multiple Heaters, One Tank Figure 6. Water Heater Piping - One Heater, Multiple Tanks Figure 7. Water Heater Piping - Multiple Heaters, Multiple Tanks 5.1 Main Power SECTION Electrical Connections4.4 Combined Water Heating potable and Space Heating - Water Heater 4.5 Freeze Protection - Water Heater5.3 External Staging Control Wiring AVERTISSEMENT6.1 Sequence of Operation SECTION Operating Instructions6.2 Programming the Temperature Control 6.2.1 System Piping “Primary Secondary Piping” “Parallel Piping”6.2.2 Choosing the Mode 6.2.3 Programming6.3.3 for more information BOIL MAX Boiler Maximum Temperature Boiler Start BOIL START The BOIL 6.2.4 Choosing the Mode for your Application Mechanical aquastat in a domestic hot water storage tank 6.3 Advanced Topics Mode 5 Primary secondary piping with outdoor reset6.3.2 Staging Mode 6.3.1 Differential6.3.3 Boiler Minimum BOIL MIN 6.3.4 Boiler Maximum BOIL MAX 6.3.5 Boiler Target Temperature6.3.6 Pump Operation 6.3.7 Set point OperationOutdoor Design OUTDR DSGN - The 6.3.9 Outdoor Reset Operation6.3.10 External Heater Operation 6.4 Operating the Burner and Set Up 6.4.1 Set Up for 0 to 2500 Feet Altitude6.3.11 Limit Controls 6.3.12 Advanced Programming ModeSECTION Maintenance 7.1 System Maintenance6.5 Shutting Down the Copper Brute 6.6 To Restart the Copper Brute7.2 Appliance Maintenance and Component Description 7.2.4 Manual Reset High Limit Control 7.2.5 Automatic Reset High Limit Control7.2.1 Burners 7.2.2 Filter7.2.12 Flow Switch 7.2.9 Ignition Sensors7.2.10 Transformer 7.2.11 BlowersSECTION Trouble Shooting 8.1 Resolving Lockouts8.2 Delayed Ignition - Possible Causes 8.3 Short CyclingERROR DISPLAYED DESCRIPTION OF ERROR8.6 Troubleshooting Copper Brute II Controls SECTION Wiring Diagrams Figure 18. Copper Brute II 500 - 750 Ladder DiagramFigure 19. Copper Brute II 1000 Ladder Diagram Figure 20. Copper Brute II 1250 - 2000 Ladder Diagram Figure 21. Copper Brute II 500 - 1000 Wiring Schematic Figure 22. Copper Brute II 1250 - 2000 Wiring Schematic Figure 23. Field Wiring Note Positions of field wiring terminals may vary, butterminal designations are as indicated Reference Only Wiring for Modes 1Figure 24. Field MODEVersion for Reference Only 25. Field Wiring for ModeInternet Copper Brute II 1250, 1500, 1750 & 2000 4-Stage Heater
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