Crown Boiler 24-12, 24-11, 24-10 Return Temperature Control and Components, CCW Open to System

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N.ELECTRIC WIRING - Install all ﬁeld wiring in accordance with the National Electric Code and Local Regulations.

Control voltage and/or 3-phase line voltage must be supplied to the burner panel box through a fused disconnect.

When using the RTC, a separate fused control circuit shall feed the control to allow the exercising of the valve actuator and boiler circulator during dormant boiler operation.

Review electrical schematics in Appendix A and Burner Electrical Diagram for more information.

O.RETURN TEMPERATURE CONTROL AND COMPONENTS

1.Valve Actuator – The valve actuator is mounted to the top of the diverting valve. Mount and connect the actuator as illustrated in Appendix C. The electrical connections depend on valve orientation. Use Figures 39a and 39b as a guide.

2.Return Sensor – A sensor has been included with the Return Temperature Control. The sensor must be mounted for proper operation. The sensor is mounted in the 3 inch NPT x 12 inch special return nipple. The sensor must be inserted into the ¼ NPT connection using pipe dope. The 3” nipple must be inserted with the sensor closest to the boiler, using the rear lower right connection. (Orientation based on viewing the boiler from the rear.) The sensor

shall be connected to the RTC through a junction box located above the nipple. Use grommets and conduit to protect the leads and connection back to the RTC controller.

3.Knock Down Boiler Installations – The installation instructions above must be followed for all knockdown boilers as well. The controller is mounted on the front jacket panel at the top right. See Figures 41 and 42 for general component

Figure 39b: Diverting Valve/Actuator Wiring

(CW - Open to System)

Figure 39a: Diverting Valve/Actuator Wiring	Figure 40a: Steam Boiler - Safety Valve Hook-Up
(CCW - Open to System)

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Contents Series Page Important Information Read Carefully Page Page Table of Contents Table of Contents Section I General Information Boiler RATINGS/DATA Locate the Unit Section I General InformationChimney or Vent Boiler FoundationVents Faults & Suggestions Assembly of Sections Manual DRAW- UP Section II Cast Iron Block AssemblyNipple Gauge Series 24 Section Arrangement Draw-Up Rods Alternating Pattern Manual Draw-up Center Section Channel Block Position Partial Block Draw-Up Hydraulic Draw-Up of Sections Canopy with Rear Flue Outlet Damper Assembly Section III Installation InstructionsBare Boiler Assembly Avoid Breathing Fiber Particulates and Dust Left Side Canopy Intermediate Bracket Inspect ALL Boiler Seals Mount Rear Observation Port Cover Refer to FigureSeries 24 Jacket Assembly Boiler Models 24-03 thru Mount Burner Adapter Plate to Burner Mounting Plate Burner Mounting Plate Refer to Figures 16Purpose of Tappings Steam Boilers Steam Trim Steam Boilers Install Steam Trim This Is Intentionally Left Blank Purpose of Tappings Water Boilers Water Trim Burner Installation Water Boilers Install Water TrimBoiler Piping Heating Applications Page Parallel Piping Conversion Recommendation 1 Use when Recommendation 2 Use when Recommendation 3 Use when Page Page Page BMounting Elevations M&M 150, 64 Float Low Water Cut-offs Schematic Tankless Heater Piping 24-08 24-09 CCW Open to System Return Temperature Control and ComponentsWater Boiler Pressure Relief Valve Hook-Up Typical Boiler Wiring with RTC Front Typical Boiler with RTC Return Sensor Rear Fill Heating System with Water Always Inspect Installation BeforeSection IV Operating Instructions Starting BurnerFlame Failure Boil MIN Delay Check Operation of High Limit Control Test ControlsBoiler and System Cleaning Steam Boiler Boiler and System Cleaning Water Boilers Oxygen Corrosion Frequent Water AdditionClean the Boiler Flueways Section V Service InstructionsMaintenance of LOW Water Cutoff Devices Operation General Maintenance ConsiderationsOIL Burners Section VI Burner SpecificationsSection VII Repair Parts & Carton Contents Series 24 Master Parts List Section VII Repair Parts Jacket Carton Bare Boiler Assembly Section Joiner Carton Assy Rear Target Wall Carton Standard Steam Trim Carton Assy RTC Carton with Outdoor Reset Tankless Coil Components Boiler Water Section Viii Appendix Page Mechanical Page Mechanical Electrical Page Page Page Page Page Page Page Page Series 24 Boiler Circulator Selection Taco 20F Differential Boiler Recirculation Grundfos Circulating Pump Way Boiler Recirculation Bell and Gossett Circulating Pump Way Boiler Recirculation Armstrong Circulating Pump Way Application Appendix C Valve and Actuator Mounting InstructionsService Record PN 980417 S24 12/05