Bradford-White Corp Modulating Boiler Hydronic Heating Using Local Lead- Lag/Cascading Feature

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Brute Elite

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setpoint is used to limit the maximum water temperature leaving the boiler only. The modulation rate is controlled by a 4-20mA (0-10Vdc using converter) signal supplied by an external control. When setting up a system using an external control care must be taken to set the external control algorithms to prevent the boiler from short cycling or "hunting " to prevent premature component failure.

9.5Hydronic Heating Using Local Lead- Lag/Cascading Feature

When using single or multiple Brute Elites in lead lag configuration, the system sensor and TT terminals of the Master boiler create heat demand. The TT terminals on the slave boilers are ignored as the demand for those heaters is given from the master control. The system sensor is also used to control the modulation rate of the lead lag system. (see Section 7 for wiring instructions).

Let’s consider the following example:

Three Brute Elite boilers (let’s call them “Lead”, “Slave1” and “Slave2”) tied together via Modbus 1 connection, with appropriate RMT Address (1, 2, 3). System sensor input is used to indicate common secondary loop temperature.

System setpoint = 150°F

HS (hysteresis) = 10°F (default) BL (base load) = 50% (default) Anti-short-cycle = 5 minutes

Run sequence is initiated when system temperature falls to 140°F (setpoint less hysteresis value). Lead boiler will start. All firing rates will depend on several application characteristics, including flow rate, system load, water volume, etc. Boilers will start at a rate of 35%. If the load is such that Lead’s rate increases to 50%, “Slave1” will go through its startup sequence and begin firing at 35%. At this point, both boilers (Lead and Slave1) will continue to respond simultaneously to the load/system characteristics, by modulating up or down together, in relation to the relative system setpoint and load characteristics.

Scenario 1: If the system loop temperature rises quickly, and moves above setpoint, then the boilers will simultaneously drop their firing rate. If when reaching the point where both boilers drop toward their minimum firing rate (20%), then the first slave will drop out. Slave1 will remain unavailable until its ASC timer has expired (5 minutes). If the load were to increase such to drive all active boilers to 50% firing rate or more, during the ASC time, Slave2 will begin its startup se- quence and begin to fire at 35%, etc.

Scenario 2: If the system loop temperature continues to drop (load increases), then the two boilers will increase firing rate together. At 50%, Slave2 will begin its firing sequence and be added to the group.

All three boilers will continue to fire simultaneously at equal input rates or…

1.Modulation rate approaches minimum firing rate (20%), in which case Slave2 will first drop out, and then Slave1, accordingly.

2.System temperature reaches 10F (HS- hysteresis value) above setpoint (e.g. 160F), in which case remaining boiler will shut off

3.Any of the boilers approach its high limit tempera- ture the individual boiler will modulate back.

9.6Hydronic Heating Using Local Lead- Lag/Cascading Feature with Indirect Hot Water

When using the lead lag boiler system to provide indirect domestic hot water heating, the DHW demand should be supplied to the master boiler through the existing DHW terminals. The lead lag system will change the operating mode of the Master boiler only to supply water at the DHW setpoint. The remaining boilers on the system will continue to supply hydronic heating.

When the system is supplying both hydronic heat and domestic hot water at the same time both the system pump and DHW pump contacts are closed, so special attention must be paid to allow for proper operation. During a DHW call, the master boiler pump may need to be turned off in applications serving both hydronic and domestic heating. This will cause the DHW pump to provide flow through the boiler and indirect tank (pump must be sized properly) when there is a DHW call. To turn off the boiler pump in this application the "boiler pump interrupt" jumper should be installed. The terminal block location is terminal block 5 (TB5) contacts labeled "boiler pump interrupt" in the control panel.

9.7 Warm Weather Shutdown

Warm weather shutdown overrides a hydronic call for heat when the outdoor air temperature is greater than the warm weather shutdown setpoint. Warm weather shutdown is always active whenever there is an outdoor sensor attached to the control. To avoid warm weather shutdown the warm weather shutdown temperature should be increased as necessary. The warm weather shutdown setpoint can be adjusted in SETUP mode, using the SD menu.

9.8Domestic Hot Water Demand (BNTV only)

When using the Brute Elite for DHW heating a call for heat must be supplied to the "DHW stat" terminal located on terminal block 6 (TB6). The DHW heating call can be from the supplied DHW sensor or from an aquastat. If the DHW sensor is used the heater operates to maintain the temperature at the DHW sensor. This may allow the actual heater outlet water temperature to exceed the DHW sensor setpoint. If an aquastat is used to supply the DHW demand the heaters

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Contents Document Installation and Operation InstructionsInstallation and Operation Instructions for BRUTE ELITEBrute Elite Control Setup and Operation TABLE OF CONTENTSSECTION General InformationTrouble Shooting SECTION MaintenanceReplacement Parts SECTION Modes of Operation1.1 Introduction SECTION General Information1.2 Model Identification Model NomenclatureFigure 2. Location of Components, Sizes Figure 1. Location of Components, SizesFigure 4. Location of Components, Size Figure 3. Location of Components, SizeFigure 6. Location of Components, Size Figure 5. Location of Components, SizeFigure 7. Location of Components, Sizes 750 and 1.6 Dimensions 1.4 Warranty1.3 Appliance Overview 1.5 UnpackingDimensions are nominal and are shown in inches, cm Figure 9. Dimensional Drawing, Sizes2.1 Locating the Appliance Brute Elite is for indoor installations onlySECTION Locating the Appliance 3.1 Combustion Air SECTION Venting and Combustion Air3.1.1 Combustion Air From Room 3.1.2 Ducted Combustion AirTable 5. Required Exhaust Vent Material 3.2 VentingFigure 10. Combustion Air and Vent Through Roof 3.2.1 Venting Requirements Unique to Canada 3.3 Locating Vent & Combustion Air TerminalsA. exhaust vent terminal not included E. CPVC exhaust pipe section 80-500 not incl3.3.2 Side Wall Combustion Air Terminal 3.3.5 Installations in the Commonwealth of Massachusetts5. For concentric vent, follow instructions included with vent kit 3.3.3 Vertical Vent TerminalFigure 12. Combustion Air and Vent Through Side Wall 2. Approved Carbon Monoxide Detectors 3.4 Common Vent Test3. Signage 4. Inspection3. Refer to Tables 6A, 6B, 6C and 6D to size piping SECTION Gas Supply and Piping4.1 Gas Supply and Piping 5.1 Brute Elite Boiler Flow and Head Requirements see Table SECTION Pump Requirements5.2 Brute Elite Water Heater Flow and Head Requirements see Table Table 6A6A.2 BNTH Cold Water Make-Up SECTION 6A Water Connections - BNTH Boiler6A.1 BNTH System Piping Hot Supply Connections 6A.3 Freeze Protection 6A.4 BNTH Suggested Piping Schematics6A.5 Recognized Chemicals 1. Sentinel Performance Solutions Group 2. Hercules Chemical CompanyFigure 15. Hydronic Piping - Single Boiler zoning with circulators Page Figure 17. Hydronic Piping - Multiple Boilers zoning with circulators Page Brute ElitePage Page Brute ElitePage 6B.1 BNTV Water Quality SECTION 6B6B.2 Piping Requirements Water Connections - BNTV Water Heater6B.3 Cold Water Make-Up 6B.5 BNTV Suggested Piping Schematics6B.4 Freeze Protection 6B.6 BNTV Suggested PumpsFigure 26. DHW Piping, Two Heaters, Two Vertical Tanks Figure 25. DHW Piping, Two Heaters, One Vertical TankCaution Pump sizing must be based opon water hardness at job siteSECTION Electrical Connections 7.1 Main Power7.2 Pump Connections 7.10 Lead Lag/ Cascading Wiring Connections7.3 24Vac Transformer with Integral Circuit Breaker 7.4 Hydronic Call for HeatFigure 28. Lead-Lag / Cascading Wiring Connections Figure 29. Ladder Diagram 7.11 Wiring Diagrams see Figures 29 andFigure 30. Wiring Diagram all sizes 8.2 Ignition Control- Sequence of Events SECTION Brute Elite Control Setup and Operation8.1 Display Navigation 8.5 Anti-Short Cycle ASC 8.3 Modulation Control8.5 High Limit 8.7 Outlet Water Temperature8.13 Boiler Pump Interrupt 8.12.5 Lead Lag Base Load Setting8.12.1 Lead Lag Setpoint 8.12.2 Lead Lag Master/Slave Selection9.4 Hydronic Heating Using External Modulation Control 9.2 Hydronic Heating with Outdoor ResetSECTION Modes of Operation 9.1 Hydronic Heating Demand9.7 Warm Weather Shutdown 9.5 Hydronic Heating Using Local Lead- Lag/Cascading Feature9.8 Domestic Hot Water Demand BNTV only Let’s consider the following example9.9 Domestic Hot Water Heating Using External Modulation Control SECTION Operating Instructions 10.2 Operating the Burner and Set Up10.1 Filling the Boiler System 10.2.1 Burner Operation10.3 Shutting Down Brute Elite 10.2.2 Boiler Setup and Adjustment10.4 To Restart Brute Elite 3. WAIT FIVE 5 MINUTESFigure 33B. Brute Elite Gas Valves 600, 750 and 80-285Figure 33A. Brute Elite Gas Valves 285, 399 and 11.1 System Maintenance SECTION Maintenance11.2 Appliance Maintenance and Component Description yearly, unless otherwise notedIgniters and sensors get hot and can cause burns or injury 11.2.4 Ignitor Assembly11.2.5 Flame Sensor 11.2.8 Heat Exchanger Coils 11.2.6 Transformer with Integral Circuit Breaker11.2.7 Blower 12.3 Error Codes - See Table SECTION Trouble Shooting11.2.9 Gas Pressure Switches optional 12.1 Sequence of OperationSOLUTION PROBLEMcontinued next page CODE#see Section Table 18. Error Codes13.2 Parts List SECTION Replacement Parts13.1 General Information Jacket Components - See FigureGas Train Components - See Figure Heat Exchanger Components - See Figure Electrical Components - See Figure Contact Customer Service at 800 900-9275Figure 35. Jacket Components Figure 36B. Internal Components, Sizes Figure 36A. Internal Components, SizesFigure 36C. Internal Components, Sizes Figure 37A. Gas Train Components, Sizes Figure 37B. Gas Train Components, Sizes Figure 38. Heat Exchanger Components Figure 39. Electrical Components Page Service Parts 800 Tech. Service 800Warranty Service 800 Ambler, PA
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