Figure 11.4: Outdoor Reset Curve

7)The sequence of operation for a BWC series boiler on a call for heat from a thermostat is as described below:

a)When power is first turned on, 120V is provided to the MCBA, the combustion fan and the LWCO trans- former. A separate 50VA transformer, connected directly to the MCBA, powers all other low voltage circuits.

b)For the first few seconds after power-up the control module goes through a self check.

c)When there is a call for heat, the control module checks to make sure the air pressure switch is open. If it is, the combustion fan will be energized and will ramp up to ignition speed. When the air pressure switch closes, a 10 second prepurge is activated.

d)After the prepurge, the control module energizes the gas control valve and the spark for 4.5 seconds. If a flame is established and proved, the control allows the flame to stabilize for 5 seconds at the combustion fan ignition speed setting. If the flame fails to prove, the control module will attempt to light the burner 4 more times. If a flame is still not established, the control will lockout.

e)Once the flame stabilization period has ended, the MCBA allows the burner to modulate. The actual firing rate is dependent upon the measured current and recent differences between the set point temperature and the supply temperature. If an outdoor sensor is connected to the control module and the boiler is responding to a call for heat, the set point temperature will be determined by the outdoor reset curve shown in Figure 11.4.

f)Once the set point temperature is reached, the MCBA will turn the burner off and allow the combustion fan to operate in postpurge for 35 seconds before it turns off.

g)The central heating pump will continue to operate until the room thermostat has been satisfied.

h)A demand for domestic hot water (DHW) is given priority on BWC series boilers. If a call for DHW is received while the boiler is responding to a call for heat, the heating circulator is deenergized until the call for DHW is satisfied.

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Crown Boiler BWC Series installation instructions Outdoor Reset Curve
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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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