Crown Boiler BWC Series Method 1 Primary/Secondary Piping Boiler in Secondary Loop

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Method 1: Primary/Secondary Piping - Boiler in Secondary Loop

This method can be used in heat-only applications as shown in Figure 8.2 or with an indirect water heater as shown in Figure 8.3. This method relies on primary/secondary pumping to ensure that the required flow is always maintained through the boiler. In this system, the flow rate through the boiler is completely independent of the flow rate through the heating system. Use the following guidelines to ensure that boiler will have the required flow shown in Table 8.1 regardless of the flow in the heating system.

1)Primary Loop Piping - Size the primary circulator and piping to obtain the design flow rate through the heating system as you would on any other heating system. All piping between the expansion tank and secondary connection tees must be at least as large as that shown in Table 8.5, column a. In order to keep the flow rates in the primary and secondary loops independent of each other, provide at least 8 diameters of straight pipe upstream of the first secondary tee and 4 diameters downstream of the second secondary tee. Keep the distance between the expansion tank and the first secondary tee as short as practical.

2)Secondary Loop (“Boiler Loop”) Piping – All piping must be the size shown for the boiler in Table 8.5, column a. To size the circulator:

a)Count all fittings in the planned secondary loop (the secondary loop consists of the shaded piping in Figure

8.4a). In doing so, do not count the secondary connection tees, unions, or the fittings supplied with the boiler (these have already been accounted for).

b)Using Table 8.7, find the equivalent lengths of all fittings in the secondary loop. Total these equivalent lengths and add them to the total length of planned straight pipe in the secondary loop. The result is the total equivalent length of the secondary loop.

c)Using Table 8.5, find the boiler size being installed and select a boiler secondary circulator that shows a “maximum equivalent length” (column d) in excess of the total equivalent length calculated in Step b.

3)Indirect Water Heater Loop Piping (If Indirect Water Heater is Used) – All piping must be the size shown in Table 8.6, column (a). If the indirect water heater connections are smaller than the pipe size called for in column (a), reduce the pipe size at the indirect water heater connections. To size the circulator:

a)Count all fittings in the planned Indirect Water Heater Loop (the indirect water heater loop consists of the shaded piping in Figure 8.4b). In doing so, you will be counting some piping and fittings which are common to the heating system secondary (“boiler loop”) piping and which were counted in Step 2a above. Do not count the elbows or fittings supplied with the boiler.

b)Using Table 8.7, find the equivalent lengths of all fittings in the indirect water heater loop. Total these equivalent lengths and add them to the total length of planned straight pipe in the indirect water heater loop. The result is the total equivalent length of the indirect water heater loop.

c)Using Table 8.6, find the boiler size being installed and select an indirect water heater loop circulator that shows a “maximum equivalent length” (column f) in excess of the total equivalent length calculated in Step b.

Example – Assume that a BWC150 is to be installed in a heating system along with a Crown MS-40

indirect water heater. A total of 15 ft of straight pipe will be installed between the boiler and the primary loop. A total of 20 ft of straight pipe will be installed between the boiler and the indirect water heater. Fittings are arranged as shown in Figure 8.3. The MS-40 requires a flow rate of 8 GPM and has a head loss of 3.0 ft.

Total fittings in Secondary loop (“boiler loop”):

7 90 Elbows

2 Runs of Tees

1 Swing Check

2 Isolation Valves

Note: Unions, Secondary Connection Tees, and factory supplied fittings are ignored.

Calculate total equivalent length from Table 8.7:

15ft Straight Pipe + 7 Elbows x 3.75 + 2 Runs of Tees x 2.5 + 1 Swing Check x 10 + 2 valves x 0.8 = 57.85 Equivalent Feet Straight Pipe. From Table 8.5, we see that a Taco 007 will pump 8 GPM through a BWC150 with 148 equivalent feet of pipe, so Taco 007 is OK.

Total fittings in Indirect Water Heater Loop:

6 90 Elbows

2 Turns in Tees

1 Swing Check

2 Isolation Valves

Calculate total equivalent length from Table 8.7:

20 Straight Pipe + 6 Elbows x 3.75 + 2 Turns in Tees x 8 + 1 Swing Check x 10 + 2 valves x 0.8 = 70.1 Equivalent Feet Straight Pipe. From Table 8.6, we see that smallest circulator which will pump at 8 GPM through a BWC150 with 70.1 equivalent feet and an indirect water heater pressure drop of 3 ft is a Taco 0010.

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Contents BWC Series Page VII Product Description II SpecificationsIII Before Installing IV Locating the BoilerMinimum Clearance To Combustible Material Air for Ventilation Page VI Venting Vent System DesignHorizontal Direct Venting Vent Options 1,2 2a Summary of Horizontal Venting Options 3c Positioning Vent Terminal Under Overhangs Vertical Direct Vent System Vent Options 6 2b Summary of Vertical Venting Options VENT/ AIR Intake Fitting Equivalent Length Vent / Intake System Assembly Removing an Existing Boiler From a Common Chimney7a STAR-34 Connection to Vent Collar Z-VENT III Connection to Vent Collar SAF-T Vent Ezseal Connection to Vent Collar 10 Fasnseal Connection to Vent Collar 11 Condensate Piping Arrangement VII Gas Piping Gas Connection To BoilerGeneral System Piping Precautions Viii System PipingSystem Design Method 1 Primary/Secondary Piping Boiler in Secondary Loop Piping Method #1 Heat Only 4a Piping Method #1 Secondary Loop Piping Shaded Pipe and Circulator Sizing for Boiler Loop Fitting Equivalent Lengths Method 2 Primary/Secondary Piping Boiler in Primary Loop Piping Method #2 Heat Only 10a Piping Method #2 Secondary Loop Piping Bolded Page Flow GPM Piping for Special Situations 14 Chiller Piping IX Wiring Wiring Connections Diagram Ladder Diagram Page Start-up and Checkout For Your Safety Read Before Lighting BWC Series Lighting and Operating InstructionsBWC Burner Gas Valve Detail Typical CO2/O2 Combustion ReadingsPage Normal Display In Standby Mode XI OperationPage 170 Boiler Status First Digit Boiler StatusOutdoor Reset Curve XII. Service and Maintenance ContinuouslyPage XIII. Troubleshooting No Error Code DisplayedSoft Lockout Codes Displayed Code Condition Possible CausesHard Lockout Codes Displayed XIV Parts BWC Replacement Parts List TBD Page Page Page Page Ignition Electrode Gasket, 5mm 240011 Page BWC Replacement Parts List Page Page Page Page Page PN 980040 BWC 08/05

BWC Series specifications

The Crown Boiler BWC Series is a modern choice for heating needs, renowned for its efficiency and robust design. This series offers a range of residential and light commercial heating applicabilities, ensuring both comfort and reliability for users.

One of the standout features of the BWC Series is its efficiency. Crown Boilers utilize advanced technologies to maximize energy output while minimizing fuel consumption. With an AFUE (Annual Fuel Utilization Efficiency) rating often exceeding 90%, users can expect significant cost savings on their energy bills over time.

The BWC Series employs a high-quality, stainless steel heat exchanger, which not only enhances performance but also extends the lifespan of the boiler. This heat exchanger is designed to transfer heat efficiently, ensuring that the maximum amount of energy from the fuel is converted into usable heat. Additionally, the design helps to prevent corrosion and maintain system integrity over years of usage.

For technological advancements, the BWC Series incorporates a modulating gas valve which allows for precise control over the boiler's operation. This feature enables the system to adjust its output based on the heating demands of the home, resulting in improved energy efficiency and consistent comfort levels. Moreover, this modulating technology reduces the frequency of cycling, thereby prolonging the lifespan of the unit and minimizing wear and tear.

Another characteristic of the Crown Boiler BWC Series is its user-friendly interface. The boiler is equipped with a simple control panel that allows for easy monitoring and adjustment of settings. This accessibility is essential for users who want to manage their heating system without the need for extensive technical knowledge.

In terms of installation and maintenance, the BWC Series is designed with convenience in mind. Its compact footprint allows it to fit comfortably in a variety of spaces, making it an ideal choice for homes with limited installation areas. Additionally, Crown Boiler's commitment to high manufacturing standards ensures that the units require minimal maintenance, providing peace of mind to homeowners.

Overall, the Crown Boiler BWC Series is an excellent solution for those seeking efficient, reliable heating. Its combination of advanced technology, quality construction, and user-friendly design makes it an attractive option for any residential or light commercial application. Whether replacing an old system or installing a new one, the BWC Series delivers comfort and performance that can be depended upon.
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