Bradford-White Corp PE4403S*F(BN,SX), PE4503*F(BN,SX) service manual Normal Heating Sequence cont’d

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Sequence of Operation

Normal Heating Sequence (cont’d)

7.Steady State Operation: During steady state operation, the gas control monitors:

Thermostat Temperature Sensor: When the setpoint temperature is satisfied, the gas control is shutdown, and power is removed from the relay. The gas control LED flashes a short flash once every 4 seconds (Idle status code).

Relay Status: If the relay is altered during a call for heat, the pilot and main valves are shutdown. The relay is powered attempting to close the safety circuit. The gas control LED flashes 3 times with a 3 second pause.

Flame Sensor: If flame is lost, the pilot and main valves are shutdown. The relay is powered. The gas control attempts to re-light the pilot 4 times. If unsuccessful, power is removed from the relay, and the gas control proceeds to a 5 minute lockout. The gas control re-attempts to light the pilot starting at Normal Heating Sequence #2.

8.Thermostat Satisfies: Gas control LED flashes once every 4 seconds.

9.Burner Off

10.Relay De-energized (15 seconds)

Abnormal Operation

1.Flammable Vapor Sensor Fault:

A)If the resistance is greater than 70,000 ohms: The gas control immediately turns off all outputs. The gas control waits and monitors resistance for 30 seconds. If the resistance is greater than 65,000 ohms after 30 seconds, the gas control proceeds to verify resistive delay for 2 minutes and flashes 7 times then 1 time with a three second pause. This process is repeated 5 times until the control either returns to normal operation or proceeds to flammable vapor lockout.

B)If the resistance is below 3000 ohms: The gas control immediately turns off all outputs and proceeds to flash 8 times then 1 time with a three second pause. The error self clears if the resistance returns to normal range for at least 15 seconds.

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Contents Service Manual Table of Contents Page Page Bradford White Defender Safety System IntroductionHow to Use this Manual How to Use this Manual Specifications SpecificationsControl Timings Normal Heating Sequence Power Up SequenceSequence of Operation Relay EnergizedNormal Heating Sequence cont’d Safety Circuit Fault Abnormal Operation cont’d Temperature Sensor FaultTrial for Ignition Fault Abnormal Operation cont’d Flame Sensing Fault Troubleshooting LED Status Control Status Probable Cause Service ProcedureTroubleshooting Gas Valve / Control Model LED Status Accessory Module Probable Cause Burner Cleaning Procedure Burner MaintenanceBurner Inspection Unscrew the burner from the main burner orifice Burner Cleaning Procedure cont’d Pilot Inspection, Testing, and ReplacementPilot Maintenance Pilot Inspection, Testing, and Replacement cont’dThermal Well Testing Thermal Well Testing cont’d Thermal Well TestingDetermine Water Temperature Inside Tank Determine Water Temperature Inside Tank cont’d Determine Tank TemperatureSensor Resistance at Various Temperatures Component Disassembly Gas Control & Thermal Well Removal From Water HeaterGas Control Removal Gas Control Removal From Thermal WellGas Control Assembly to the Thermal Well Gas Control Removal From Thermal Well cont’dGas Control Assembly to the Thermal Well cont’d Gas Control AssemblyFlammable Vapor Sensor Testing Relay Replacement Flammable Vapor Sensor TestingFlammable Vapor Sensor Testing cont’d VAC Circuit TraceRelay Replacement Relay Replacement cont’dCommon Terms Common TermsParts List Part Name and DescriptionParts@bradfordwhite.com Techserv@bradfordwhite.com
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