Crown Boiler 24-12, 24-11, 24-10, 24-08, 24-06, 24-05, 24-09, 24-03, 24-04, 24-07 installation instructions

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WARNING

A hot water boiler installed above radiation level must be provided with a low water cutoff device as part of the installation.

1.HOT WATER HEATING - This boiler must be installed in strict accordance to the instructions found in this installation manual. Deviations from these installation instructions may void manufacturer’s warranty. See warning below to determine the use of the RTC. A Return Temperature Control (RTC) may be provided to protect the boiler from thermal shock and sustained condensing operation. In addition, a properly selected boiler circulator and diverting valve, along with the return sensor, must be installed when using the RTC. A number of typical Crown applications have been added to the appendix (Appendix A). Select the appropriate application before proceeding.

a.Parallel Piping Systems – An existing parallel piping system may be used, provided the return water is not below 135°F for prolonged periods of time, and the return water temperature is not more than 40°F less than the idle boiler temperature (see warning below). A flow analysis should be performed to determine the flow through the boiler when the minimum (and smallest) and maximum number of zones are activated. A sufficient flow through the boiler should be maintained to assure a maximum of 40°F difference between the boiler supply and return.

If the conditions above cannot be met, then parallel piping systems must be converted to a primary/secondary arrangement, de-coupling the system pump from the boiler loop. The system pump cannot influence the flow through the boiler(s) in a primary/secondary piping arrangement. The concept must be for the boiler loop to inject heat into a primary loop, provided the return water into the boiler is at least 135°F.

A by-pass containing two closely spaced tees must be installed to de-couple the boiler loop from the primary loop (see Figure 30). Care must be taken to avoid dead heading the system pump. Conversions should be reviewed and approved by a Consulting Engineer or other qualified professional to avoid system deficiencies.

b.Primary/Secondary Piping – Boiler(s) must be installed into a heating system that is (are) designed as a primary/secondary piping arrangement when the flow through the boiler cannot be maintained to provide a 20°F - 40°F difference between the boiler supply and return. When using an RTC, the boiler loop contains a boiler, boiler circulator and diverting valve, along with the return temperature control (RTC) and return sensor. The diverting valve consists of a 3-way valve, positioned through the use of an electronic actuator. The boiler loop injects heat into the primary loop, provided the temperature of the boiler return water is greater than 135°F. If the temperature is below 135°F, the diverting valve closes, recirculating the boiler water until it has heated above the 135°F minimum limit. The supply and return of the boiler loop is connected to the primary loop through the use of two closely spaced “Tees”, at a maximum branch centerline distance of 4 times the primary loop diameter (4 x D Max.) The RTC provides a signal to the actuator based on the absolute water temperature and the rate of change in water temperature.

c.Multiple Boilers – Multiple boilers are installed the same as single boiler installations. Each boiler loop will contain it’s own boiler circulator, diverting valve, RTC and return sensor (see Appendix A). Commonly available sequencers can be used in conjunction with the Return Temperature Control by energizing the control’s heat demand circuit. The outdoor reset feature of the sequencer must be used in multiple boiler installations. The outdoor reset feature

WARNING

Return water cannot be lower than 135°F for prolonged periods of time. Operation under these conditions will result in sustained condensing within the combustion chamber and potentially reduce boiler longevity.

In addition, the return water cannot be introduced into the boiler if it is more than 40°F less than the idle boiler temperature. Continued operation under these conditions may result in premature boiler failure through thermal shock.

Example: A boiler that has been idle for some time since the last heat demand cycle may have it's boiler water temperature reduced to 150°F. The return temperature from the next zone activation cannot be less than 110°F.

If the above conditions exist, an RTC system must be installed to protect the boiler from sustained condensing operation and thermal shock.

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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 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 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 Section IV Operating Instructions Always Inspect Installation BeforeStarting Burner Fill Heating System with WaterFlame 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
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