Bradford-White Corp Modulating Boiler, BNTH Modulation Control, Anti-Short Cycle ASC, High Limit

Page 38

Page 38

BRADFORD WHITE CORP.

 

 

 

 

4.Prepurge timer is started once the prepurge RPM is achieved.

5.Pre ignition time of 2 seconds to check the flame sensor operation and status. During this period an intermittent spark can be seen.

6.Trial for ignition period, 4 seconds. The direct spark ignition switches to constant spark for three seconds, during which time the gas valve is open. For the last second of the ignition period direct spark is de-energized and the flame sensor checks for established flame. If flame is sensed the control enters "Run" to satisfy the demand. If flame is not established the control enters a retrystarting from step 2. If flame has not been established in the appropriate number of retries the control will lockout with a 109 error code.

7.Call for heat complete

8.Gas valve off

9.Fan and pump over run times active to purge the system

This sequence is the basic operating sequence of the appliance whether there is a DHW, or hydronic call for heat.

8.3 Modulation Control

The control uses a PID algorithm to adjust the firing rate of the boiler as the control point is approached. The goal of the control is to operate at a minimum firing rate to match the load on the appliance. This is done by using a setpoint, and on / off differentials. The control modulates to achieve the setpoint temperature, which could be several degrees away from the actual off point. The off point is calculated by adding the setpoint + off differential. The setpoint and differentials used in operation is dependent upon the call for heat being applied. If there is a DHW call the DHW setpoint and off differentials are used. If there is a hydronic call the CH setpoint and off differential is used. When the setpoint + off differential is achieved the control interrupts appliance firing until the water temperatures reaches the setpoint - on differential. Both the hydronic and DHW setpoints are adjustable through the USER mode menu structure.

8.5 Anti-Short Cycle (ASC)

The anti short cycle period is started whenever the gas valve turns off. This period is to help prevent short cycling. Depending upon the time selected the control will wait up to 10 minutes before attempting to start the trial for ignition sequence. The ASC time can be adjusted by entering setup mode.

8.5 High Limit

The control uses a dual thermistor sensor to monitor the Brute Elite's maximum temperature. The high limit sensor is installed in the outlet water. A dual thermistor sensor is used, so that the two temperatures can be monitored and compared to confirm accuracy. The control will automatically reduce the firing of the Brute Elite to prevent the high limit from tripping. The high limit setpoint is not adjustable.

8.7 Outlet Water Temperature

The outlet water temperature is a dual thermistor sensor and is limit rated. The control compares each of the temperature readings to determine accuracy. The outlet sensor is used as the primary control point for high limit, temperature operation, and modulation. The operating setpoint can be adjusted through the USER menu structure.

8.8 Inlet Water Temperature

The inlet water temperature uses a single thermistor sensor and is used to calculate the delta T of the system.

8.9 Heat Exchanger Temperature Rise

The heat exchanger temperature rise is calculated from the outlet and inlet sensor temperatures. The result is displayed in the USER menu structure.

8.10 Stack Temperature

The stack temperature is a dual thermistor sensor and is limit rated. The control compares each of the temperature readings to determine accuracy. The stack sensor is used as a limiting feature to avoid excessive temperatures in the venting.

8.4 Pump Control

The control can operate three pumps. The boiler pump is active anytime there is a call for heat applied to the control. The DHW and system pumps are active based upon the call and priority of the heat demand being supplied. When there is a hydronic call supplied the system pump is active. If there is a DHW call supplied while the hydronic call is active the system pump turns off and the DHW turns on. This happens because of domestic hot water priority, which forces the control to attempt to satisfy the domestic water demand prior to the hydronic demand. When the last heat demand is satisfied the boiler pump enters an overrun time.

8.11 Domestic Hot Water Temperature

The domestic hot water temperature sensor is used to monitor the DHW demand. The control uses the DHW sensor to control the operation and modulation rate of the appliance when there is a DHW demand. The DHW setpoint can be adjusted through the USER menu structure.

8.12 Lead Lag / Cascading

Lead Lag/Cascading allows multiple boilers to be connected together and controlled from one common sensor input. Up to 8 boilers can be connected together in a single system. To setup Lead/Lag or cascading

Page 37 Page 39
Image 38
Page 37 Page 39
Contents Installation and Operation Instructions for Installation and Operation InstructionsDocument BRUTE ELITESECTION TABLE OF CONTENTSBrute Elite Control Setup and Operation General InformationReplacement Parts SECTION MaintenanceTrouble Shooting SECTION Modes of Operation1.2 Model Identification SECTION General Information1.1 Introduction Model NomenclatureFigure 1. Location of Components, Sizes Figure 2. Location of Components, SizesFigure 3. Location of Components, Size Figure 4. Location of Components, SizeFigure 5. Location of Components, Size Figure 6. Location of Components, SizeFigure 7. Location of Components, Sizes 750 and 1.3 Appliance Overview 1.4 Warranty1.6 Dimensions 1.5 UnpackingFigure 9. Dimensional Drawing, Sizes Dimensions are nominal and are shown in inches, cm2.1 Locating the Appliance Brute Elite is for indoor installations onlySECTION Locating the Appliance 3.1.1 Combustion Air From Room SECTION Venting and Combustion Air3.1 Combustion Air 3.1.2 Ducted Combustion AirTable 5. Required Exhaust Vent Material 3.2 VentingFigure 10. Combustion Air and Vent Through Roof A. exhaust vent terminal not included 3.3 Locating Vent & Combustion Air Terminals3.2.1 Venting Requirements Unique to Canada E. CPVC exhaust pipe section 80-500 not incl5. For concentric vent, follow instructions included with vent kit 3.3.5 Installations in the Commonwealth of Massachusetts3.3.2 Side Wall Combustion Air Terminal 3.3.3 Vertical Vent TerminalFigure 12. Combustion Air and Vent Through Side Wall 3. Signage 3.4 Common Vent Test2. Approved Carbon Monoxide Detectors 4. Inspection3. Refer to Tables 6A, 6B, 6C and 6D to size piping SECTION Gas Supply and Piping4.1 Gas Supply and Piping 5.2 Brute Elite Water Heater Flow and Head Requirements see Table SECTION Pump Requirements5.1 Brute Elite Boiler 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.5 Recognized Chemicals 6A.4 BNTH Suggested Piping Schematics6A.3 Freeze Protection 1. Sentinel Performance Solutions Group 2. Hercules Chemical CompanyFigure 15. Hydronic Piping - Single Boiler zoning with circulators Brute Elite Figure 17. Hydronic Piping - Multiple Boilers zoning with circulators Brute Elite PagePage Brute Elite PagePage 6B.2 Piping Requirements SECTION 6B6B.1 BNTV Water Quality Water Connections - BNTV Water Heater6B.4 Freeze Protection 6B.5 BNTV Suggested Piping Schematics6B.3 Cold Water Make-Up 6B.6 BNTV Suggested PumpsCaution Pump sizing must be based opon Figure 25. DHW Piping, Two Heaters, One Vertical TankFigure 26. DHW Piping, Two Heaters, Two Vertical Tanks water hardness at job site7.1 Main Power SECTION Electrical Connections7.3 24Vac Transformer with Integral Circuit Breaker 7.10 Lead Lag/ Cascading Wiring Connections7.2 Pump Connections 7.4 Hydronic Call for HeatFigure 28. Lead-Lag / Cascading Wiring Connections 7.11 Wiring Diagrams see Figures 29 and Figure 29. Ladder DiagramFigure 30. Wiring Diagram all sizes 8.2 Ignition Control- Sequence of Events SECTION Brute Elite Control Setup and Operation8.1 Display Navigation 8.5 High Limit 8.3 Modulation Control8.5 Anti-Short Cycle ASC 8.7 Outlet Water Temperature8.12.1 Lead Lag Setpoint 8.12.5 Lead Lag Base Load Setting8.13 Boiler Pump Interrupt 8.12.2 Lead Lag Master/Slave SelectionSECTION Modes of Operation 9.2 Hydronic Heating with Outdoor Reset9.4 Hydronic Heating Using External Modulation Control 9.1 Hydronic Heating Demand9.8 Domestic Hot Water Demand BNTV only 9.5 Hydronic Heating Using Local Lead- Lag/Cascading Feature9.7 Warm Weather Shutdown Let’s consider the following example9.9 Domestic Hot Water Heating Using External Modulation Control 10.1 Filling the Boiler System 10.2 Operating the Burner and Set UpSECTION Operating Instructions 10.2.1 Burner Operation10.4 To Restart Brute Elite 10.2.2 Boiler Setup and Adjustment10.3 Shutting Down 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 11.2 Appliance Maintenance and Component Description SECTION Maintenance11.1 System Maintenance 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 11.2.9 Gas Pressure Switches optional SECTION Trouble Shooting12.3 Error Codes - See Table 12.1 Sequence of Operationcontinued next page PROBLEMSOLUTION CODE#Table 18. Error Codes see Section13.1 General Information SECTION Replacement Parts13.2 Parts List Jacket Components - See FigureGas Train Components - See Figure Heat Exchanger Components - See Figure Contact Customer Service at 800 900-9275 Electrical Components - See FigureFigure 35. Jacket Components Figure 36A. Internal Components, Sizes Figure 36B. 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 Brute Elite Warranty Service 800 Tech. Service 800Service Parts 800 Ambler, PA
Top Page Image Contents