Crown Boiler 24-04, 24-11, 24-10, 24-08, 24-12, 24-06, 24-05, 24-09, 24-03, 24-07 Flame Failure

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of installation.

5.ON WATER BOILERS WITH TANKLESS HEATERS, set low limit operating control dial at 190°F and high limit dial 210°F. Operating control must be a minimum of 20° below high limit setting. Set differential at 25°.

D.ADJUST BURNER according to the Burner Manual.

1.FLAME FAILURE

The Series 24 boiler controls operate the burner automatically. If for unknown reasons the burner ceases to fire and the reset button on the primary control is tripped, the burner has experienced ignition failure. Before pressing the reset button, call your serviceman immediately.

WARNING

Do not attempt to start the burner when excess oil or gas has accumulated in the combustion chamber, when the unit is full of vapor, or when the combustion chamber is very hot.

E.RETURN TEMPERATURE CONTROL: Initial Set-Up and Operation – The return temperature control (RTC) is an important part of the overall boiler system. The primary function of the RTC is to protect the boiler from thermal shock and sustained flue gas condensation. The RTC monitors the temperature of the water returning into the boiler through a return sensor. The RTC controls the 3-way diverting valve mounted on the supply of the boiler to prevent return water less than 135º F from entering the boiler. The boiler circulator provides constant and minimum flow through the boiler during every heat demand. Prior to the start of any boiler cycle, the diverting valve is closed to a full by-pass condition, forcing 100% boiler water re-circulation. The diverting valve opens and will continue to open provided the return sensor is satisfied. Conversely, large temperature drops will close the diverting valve to a position as to prevent low temperature return water. The RTC along with the ancillary components must be properly installed as identified in Section III, if there is any possibility of system return water temperature less than 135°F. A detailed description of the controller and it’s features can be found in the RTC Installation and Maintenance Manual.

1.Initial Start-up - Upon initial start-up, the control will be energized, identifying the control name and revision on the LED display. If wired properly, the control should be energized at all times. The RTC circuit should be supplied from a different source than the burner or boiler circuit. The RTC control should be energized at all times.

2.Testing – The RTC should be tested on initial start- up, as well as during any troubleshooting exercise.

Depressing the test button will activate a test sequence and energize the red test light on the front of the control. Each of the controllers outputs and relays will be energized and tested. One may pause the test sequence at any time by depressing the test button. See the RTC Installation & Maintenance Manual for a detailed description of the sequence and the potential error messages.

a.Return Sensor - The return sensor must be properly connected or an error message will be displayed. Both a short and an open circuit in the sensor circuit will cause an error message to be displayed and the valve will be moved to a partially open position until the error is resolved.

b.Valve Actuator – During the valve actuator test sequence, confirm that the valve travels through 90 degrees of rotation from a full closed position to a full open position. The pointer on the shaft must rotate from “10” to “0” respectively.

3.Adjust Setpoints – The RTC must have a number of setpoints adjusted for proper operation. Below is a summary, however see the RTC Installation and Maintenance Manual for more details. To activate the ADJUST menu, simultaneously depress and

hold the Item, and buttons. ADJUST will appear in the upper right hand corner of the LED display.

a.ROOM - Set desired room temperature. This will provide parallel shift to heating curve.

OUTDR DESIGN OFF

b.MIX TARGET – This represents a fixed target supply temperature when the outdoor reset feature in NOT selected. (OUTDR DESIGN = OFF) Set the MIX TARGET temperature to the designed boiler supply temperature. Example: If the boiler loop is designed to supply hot water to the system at 180ºF, set the MIX TARGET to 180ºF. This is also the same as the operating aquastat set point. The mix target is adjustable from 60°F to 200ºF. The default setting is 180°F. NOTE: This function is only for applications where the mix sensor is installed.

c.MIX DSGN – Mix design temperature represents the design heating system supply temperature when the outdoor reset feature is selected. (OUTDR DESIGN = ON) This represents the design of the system loop. If unsure of the original design temperature, set the MIX DSGN to the same temperature as the boiler operating aquastat, typically 180ºF. The MIX DSGN is adjustable from 70°F to 210ºF. The default setting is 180°F.

d.OUTDR DSGN – The outdoor design temperature represents the value used in the heat loss calculations, when the outdoor reset feature is selected. (OUTDR DESIGN = ON) If this value is unknown, use the value found in

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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 Section I General Information Locate the UnitBoiler Foundation Chimney or VentVents Faults & Suggestions Section II Cast Iron Block Assembly Assembly of Sections Manual DRAW- UPNipple 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 Section III Installation Instructions Canopy with Rear Flue Outlet Damper AssemblyBare Boiler Assembly Avoid Breathing Fiber Particulates and Dust Left Side Canopy Intermediate Bracket Mount Rear Observation Port Cover Refer to Figure Inspect ALL Boiler SealsSeries 24 Jacket Assembly Boiler Models 24-03 thru Burner Mounting Plate Refer to Figures 16 Mount Burner Adapter Plate to Burner Mounting PlatePurpose of Tappings Steam Boilers Steam Trim Steam Boilers Install Steam Trim This Is Intentionally Left Blank Purpose of Tappings Water Boilers Water Trim Water Boilers Install Water Trim Burner InstallationBoiler 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 Return Temperature Control and Components CCW Open to SystemWater Boiler Pressure Relief Valve Hook-Up Typical Boiler Wiring with RTC Front Typical Boiler with RTC Return Sensor Rear Always Inspect Installation Before Section IV Operating InstructionsStarting Burner Fill Heating System with WaterFlame Failure Boil MIN Delay Test Controls Check Operation of High Limit ControlBoiler and System Cleaning Steam Boiler Boiler and System Cleaning Water Boilers Frequent Water Addition Oxygen CorrosionSection V Service Instructions Clean the Boiler FluewaysMaintenance of LOW Water Cutoff Devices General Maintenance Considerations OperationSection VI Burner Specifications OIL BurnersSection 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 Appendix C Valve and Actuator Mounting Instructions ApplicationService Record PN 980417 S24 12/05
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