A.O. Smith 402, 400, 401, 403, 405, 404 Operating Sequence, FCB Eight-Position Dipswitch

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FCB: Eight-Position Dipswitch

The first three switches are similar to the switch setup of SW2 on the CCB. The remaining five switches are required for the function of igniter, blower, flame detection, and to address the firing stage. NOTE: When switch 5 is set to OFF (no blower), switch 3 (blower speed) is ignored.

Dipswitch Function:

 

 

Dipswitch Position

 

Switch 1: Spare:

 

 

 

 

 

Switch 2: Hi Gas pressure switch:

On =

Yes

 

Off =

No

Switch 3: Number of Blower Speeds:

On =

1 speed,

Off =

2 speed

Switch 4: Igniter used:

On =

Yes,

 

Off =

No

Switch 5: Blower used:

On = Yes,

 

Off =

No

Switch 6: Flame Checked:

On =

Yes,

 

Off =

No

Switch 7 & 8. Stage selection:

7

8

 

Stage #

 

 

Off

Off

 

Not allowed

 

On

Off

 

2

 

 

Off

On

 

3

 

 

On

On

 

4

 

*When switch 5 is in off (no blower) position, switch 3 (blower speeds) is ignored.

Example of Dipswitch configuration:

No High Gas, 1 blower speed, no igniter, no blower, flame not checked, stage 4.

Operating Sequence

NOTE: The following sequence is based on a three-stage system.

1.The EMC 5000 controller has four modes of operation: Initialization, Standby, Running, and Service. The internal CCB and FCB micros control these modes through a sequence of steps (or States) which are further described in the "UIM Operating Procedures" section.

2.When power is applied to the system, it enters the initialization mode and the following automatic functions are performed:

A. O. Smith opening screen is displayed.

The system goes through a calibration indicated by the green running LED blinking and then staying on; next the red service LED and yellow standby LEDs come on, next the stage 1 service and runnings LEDs blink ON and OFF followed by stage 2, stage 3, stage 4 and then back to stage 1, 2, 3, 4 LEDs.

Stored values are recalled from memory.

Configuration dipswitches are read.

Pending faults are recalled

Micros on all boards start running (indicated by a flashing Yellow LED near each micro)

Input sensors are read

FCB's are configurated with the number of ignition trials to run.

3.After initialization is complete (approximately 10 seconds) the system turns the green LED off and goes to the standby mode

(yellow "Standby" LED on), unless a previously stored fault has been recalled, which will send the system into the service model (red "Service" LED on). In standby mode the display shows the temperature screen and in fault mode the current error screen is displayed.

4.The system then compares the temperature read from the controlling probe (inlet or tank) to the setpoint temperature. If the temperature is less than the operating setpoint minus the differential temperature and the thermostat input is closed then a call for heat is established and the system shifts to the run mode (green "Running" LED turns on).

5.The heating sequence begins by applying power to the pump and, if selected, the powered vent and the IRI gas valve.

6.After a few seconds the blowers are turned on for 30-second pre-purge period of combustion chamber.

7.The stage one igniter is turned on.

8.After the igniter has reached a minimum of 2.8 amps, the gas valve is energized to allow gas flow to burners.

9.After an additional one second, the system checks the status of the flame through the flame rod (sensor). If the flame is not verified within 4 seconds, the gas valve is immediately shut off

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Contents Copper Boilers for Hydronic Heating HOT Water Supply Installation Operation Maintenance Limited WarrantyDimensional Data DIMENSIONS/CAPACITIES DataGAS and Electrical Requirement Dimensions Data for Outdoor Configuration Foreword Recovery CapacitiesFEATURES/CONTROLS Blocked Flue Pressure Switch Differential Pressure Switch Combustion AIR BlowerWater Flow Switch ON/OFF SwitchSafety Relief Valves Installation InstructionsRequired Ability LocationChemical Vapor Corrosion Installation ClearancesLevelling AIR RequirementsVenting Horizontal Vent Installation Installation AS Boiler Replacement System InstallationINTAKE/EXHAUST Installation Requirements GeneralType B or Standard Vent Vertical CategoryEquivalent 16 40.6 cmIII Stainless Standard Vent Horizontal CategorySteel IIIDirect Vent Vertical Category Direct Vent Vertical Exhaust ConfigurationsDirect Vent Horizontal Category Direct Vent Horizontal Exhaust ConfigurationsStainless GAL. Steel Sealed Stainless GAL.STEELHydronic Installation Internal Contaminants Space Heating ApplicationsVAC System Controller Optional GAS Connections Water Line Connections Tank Probe Installation ProcedureHard Water Conditions Tank Probe OptionalSingle boiler with horizontal tank Single boiler with vertical tank Suggested Pipe Size For Multiple Gas Appliances Propane Gas Wiring Connections Single Unit INSTALLATION, Suggested Pipe SizeDistance from Meter BTU Input BTU/HRGAS Manifold Assembly Genesis GB/GW 1000-2500 Series 400 Wiring Diagram Page Genesis GB/GW 1000-2500 Series 400 Schematic Diagram Page CCB Central Control Board FCB Flame Control Board Diagram PDB Power Distribution Board Diagram Filling and Purging Water System OperationPurging of GAS Line Inlet GAS PressureFor Your Safety Read Before Operating For Your Safety Read Before Operating Risk of Scalds Temperature AdjustmentsSetting Degree Burns on Adult Skin Control SystemGas Pressure Sensors open condition indicates fault Air Pressure Sensors open condition indicates faultWater Level Sensor open condition indicates fault CCB/FCB Indicator Lamps & FusesCCB-SW2 CCB Ten Position Dipswitch Central Control Section SW1Operating Sequence FCB Eight-Position DipswitchUIM Operating Procedures Temperature Setpoints System Control AlgorithmStages 1 and 2 will turn on in sequence from 1 to UIM ScreensStatus Displayed True Condition Input Temperature ScreenMenu Screen System Status ScreenDescription of FCB control states High Limit Differential Setpoint Adjustment Procedure Operating Setpoint Adjustment ProcedureOperating Differentialsetpoint Adjustment Procedure Fault Displayed Description Redled Lockout Hard Tank Probe Tank Remote probe shorted or open Flashing Main BurnersDeliming Tubecleaningprocedure Mechanical Removal of Deposits Replacement PartsConditions and Exceptions NEW Boiler Limited WarrantyTennessee Waltz Parkway, Ashland City, TN Phone