Sequence of Operation - Steam Boiler

1)When the boiler is energized, 24 volts is immediately applied to terminals “1” (blue) and “4” (yellow) on the vent damp- er. Assuming that there is no call for heat, and that the damper switch is in the “automatic” position, the damper will close. On boilers equipped with Hydrolevel CG400A probe type low water cut-offs, voltage is also always applied to terminals “1” (blue) and “2” (yellow) on the low water cut-off to power the water level sensing circuit.

2)Assuming that water is above the cut-off level, power will appear at terminal “3” on the CG400 LWCO or terminal “1”.

3)Assuming that steam pressure is below the pressure limit setting, power will appear on one side of relay contact 1R1 (Gray lead). Relay 1R is the R8225 mounted under the junction box.

4)A call for heat from the thermostat energizes relay coil 1R causing contacts 1R1 to make. Current then flows through con- tacts 1R1 to pin terminal “2” (orange) at the vent damper (if used) and the damper opens.

5)Once the vent damper is fully open, an end switch inside the damper will make, energizing pin “3” (red) at the damper.

If a vent damper is not present, current flows through the red jumper indicated by Note 2 in Figure A directly to the blocked vent switch.

6)Current passes from terminal “3” on the vent damper through the blocked vent switch. Under normal conditions, this switch is made and voltage will therefore immediately appear across terminals “24V” and “24V (GND)” on the ignition module.

7)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”).

8)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 ter- minal must be in excess of approximately 1.0 uA.

9)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.

10)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 - Steam Boilers

Hydrolevel CG400A Low Water Cut-off - Interrupts burner operation if the water in the boiler drops below a safe level. As the water drops past the cut-off point, the amber lamp on the CG400 will glow. The CG400 will interrupt power to the burners 15 seconds after the water level drops past the cut-off point. This feature prevents short cycling of the burners due to a bouncing water line. The burners will then remain off until 30 seconds after the water level has been raised above the cut-off point.

The CG400 is also equipped with a feature which will shut down the burners after they have been firing for 20 minutes, regardless of the water level status. The CG400 then keeps the burners off for 90 seconds, allowing the water level and any foam which is present to settle. During this 90 second interval, the green LED on the CG400 will glow. If the water level is still above the cut-off line at the end of this 90 second interval, the CG400 will restart the burners.

The vent damper will close when the low water cut-off interrupts burner operation.

Pressure Limit Control - Interrupts burner operation when the pressure in the boiler exceeds the “Cut-in” setting plus the differential setting. The “Cut-in” setting is shown on the outside of the control and is adjusted using the screw on the top of the control. The differential is adjusted using the white thumb wheel on the inside of the control. Burner operation is restored when the pressure in the boiler drops to the “Cut-in” pressure.

Blocked Vent Switch - Automatically interrupts burner operation in the event of a blocked vent condition. This switch is

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Crown Boiler 32-380ECS, 32-475ECS manual Sequence of Operation Steam Boiler, Safety Control Operation Steam Boilers
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32-380ECS, 32-475ECS specifications

Crown Boiler is renowned for its innovative and reliable heating solutions, and its models 32-475ECS and 32-380ECS are prime examples of the company’s commitment to performance and efficiency. These residential and light commercial steam boilers are designed to deliver warmth and comfort while minimizing energy consumption, all within a robust and durable framework.

One of the standout features of the Crown Boiler 32-475ECS and 32-380ECS is their adaptability to various heating applications. These boilers are sized appropriately for numerous residential settings, providing heating solutions for homes of different dimensions and layouts. Their large heating capacities, rated at 475,000 BTUs/hour for the 32-475ECS and 380,000 BTUs/hour for the 32-380ECS, are suitable for larger spaces or buildings requiring significant heat output.

Both models utilize a fire-tube design, which promotes efficient heat transfer and helps conserve fuel. This design leads to improved thermal efficiency compared to traditional designs, making them an environmentally-friendly choice for homeowners concerned about carbon footprints. Additionally, the units feature advanced natural gas burners that enhance combustion efficiency, ensuring that less fuel is consumed to achieve the desired heating level.

The Crown Boiler models also come equipped with various safety features, including a pressure relief valve and low water cutoff, which help to ensure safe and reliable operation during the boiler's lifecycle. The combination of these safety mechanisms with robust construction materials ensures long-lasting performance even under demanding conditions.

Furthermore, the 32-475ECS and 32-380ECS are designed for ease of installation and maintenance. They feature a user-friendly control system, allowing homeowners and technicians to monitor performance and make necessary adjustments easily. The serviceability of these units is enhanced by their compact design, which can save space in mechanical rooms and facilitate troubleshooting.

In summary, the Crown Boiler 32-475ECS and 32-380ECS represent an exceptional choice for those seeking efficient, reliable, and safe heating solutions. With their powerful heating capacities, advanced technology, and thoughtful design, these models exemplify Crown Boiler's dedication to quality and innovation in the heating industry. Whether for residential or light commercial use, these boilers provide the performance and efficiency that modern buildings demand.
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