Sequence of Operation, Intermittent Ignition

1)When the boiler is energized, 24 volts is immediately applied to terminals “1” (blue) and “4” (yellow) on the vent damper. Assuming that there is no call for heat, and that the damper switch is in the “automatic” position, the damper will close.

2)A call for heat from the thermostat energizes relay coil 1R (the relay on the L8148E), causing contacts 1R1 and 1R2 to make. Contact 1R1 starts the circulator. Contact 1R2 sends power to the high limit.

3)Assuming that the high limit is made, current will flow to pin terminal #2 (orange) at the vent damper and the damper will open.

4)Once the vent damper is fully open, an end switch inside the damper will make, energizing pin #3 (red) at the damper. This pin is connected through the damper harness to terminal “B1” on the L8148E. At this point in the operating sequence, 24 volts is present across “B1” and “B2”.

5)Under normal conditions, the flame roll-out switch and blocked vent switch are made. Voltage will therefore immediately appear across the “24V” and “24V (GND)” terminals on the ignition module.

6)Upon application of voltage across the “24V” and “24V (GND)” terminals, the ignition module will start an ignition spark at the pilot and apply 24 volts across the pilot valve (terminals “PV” and “MV/PV”).

7)Once the pilot is established, the pilot flame will act as a diode, converting the AC current at the electrode to a half wave DC current at the pilot’s ground strap. This DC current flows through the boiler to the “GND (BURNER)” connection on the ignition module. For the ignition module to recognize that a pilot flame is present, the DC current flowing into this terminal must be in excess of approximately 1.0 uA.

8)Once the ignition module detects the presence of a pilot flame, voltage is applied across the main valve (terminals “MV” and “MV/PV”), opening the valve and establishing main flame.

9)The way in which the ignition module handles failure to establish pilot or the loss of an already established pilot depends upon the exact ignition module supplied with the boiler. For more information on module operation, consult the ignition module instructions supplied with the boiler or the local Crown representative.

Safety Control Operation - Standing Pilot and Intermittent Ignition

High Limit - Interrupts main burner operation when the supply water temperature exceeds set point. Maximum allowable temperature is 250°F. If the high limit opens, the vent damper will close if the damper switch is in the “automatic” position. The circulator will continue to operate as long as there is a call for heat, regardless of the status of the high limit. Burner operation automatically resumes when the supply water temperature falls below set point.

Blocked Vent (“Spill”) Switch - Automatically interrupts main burner operation in the event that flue gas spills from the draft diverter opening. This switch is equipped with a reset button which must be pressed to restore normal burner operation. An open blocked vent switch is indicative of a problem with the vent system. If the blocked vent switch opens, the cause of the venting problem must be found and corrected by a qualified gas service technician before the blocked vent switch is reset.

Flame Roll-out Switch - Automatically interrupts boiler operation when flames or excessive heat are present in vestibule. The flame roll-out switch is a single use device which must be replaced by a identical switch in order to restore normal operation. An open flame roll-out switch is usually indicative of a plugged heat exchanger. The cause of the flame roll-out must be found and corrected by a qualified gas service technician, and the switch replaced with an identical one, before the boiler is returned to operation.

AWI262, AWI095, TWI095, AWI195, AWI037 specifications

Crown Boiler is a renowned name in the heating industry, providing high-quality, efficient heating solutions that cater to various residential and commercial needs. Among its impressive lineup, the AWI and TWI series stand out for their design, technology, and performance.

The Crown Boiler AWI061 and TWI061 are part of the Hydronic Boiler range, designed to deliver efficient hot water heating. The AWI series features an advanced pressure-jet design that allows it to operate with exceptional fuel efficiency, reducing operating costs for homeowners and businesses alike. Additionally, these models come equipped with an integrated pump system that ensures a consistent supply of hot water, making them ideal for both space heating and domestic hot water applications.

Meanwhile, the AWI162 and AWI128 models are engineered for higher output, addressing larger heating needs without compromising efficiency. These models showcase a robust heat exchanger made of durable cast iron, promoting longevity and effective heat transfer. The AWI series boilers feature a modern control system that allows for precise temperature management, enhancing comfort while minimizing energy consumption.

The Crown Boiler AWI295, on the other hand, steps up with a significant heating capacity suited for commercial applications. This model is designed with advanced safety and efficiency technologies, including an intelligent control module that monitors temperature and pressure, ensuring optimal performance while preventing malfunctions. The large water volume design allows for enhanced thermal stability and consistent heating output.

A notable characteristic across these models is their ease of installation and maintenance. Crown Boiler has engineered the units with user-friendly features, including accessible components and simplified diagnostics that help technicians service the boilers swiftly. Moreover, the durability of cast iron construction ensures that these units can withstand high thermal stress while delivering reliable performance over the years.

In summary, Crown Boiler’s AWI061, TWI061, AWI162, AWI128, and AWI295 models offer a range of solutions equipped with advanced technologies and features designed for efficiency and reliability. These boilers are suitable for diverse heating needs, promising optimal comfort and convenience in both residential and commercial settings. With Crown Boiler's longstanding commitment to quality, customers can be assured of a robust heating solution backed by exceptional service.