Roberts Gorden UHD[X][S][R] 125 Ignition Control, Limit Switches Removal and Replacement

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SECTION 14: REPLACEMENT PARTS

14.6 Pressure Switch

Pull off 3 way connector. Spring open plastic clips of mounting cradle. Replace with correct type of pressure switch for model. The pressure switches are color coded for each pressure setting.

Carry out a start-up after working on or changing a pressure switch. See Page 23, Section 10.

MODEL	UHD[X][S][R] 75	UHD[X][S][R] 100	UHD[X][S][R] 125

Pressure Switch Kit P/N	90439810	90439810	90439803

Color Code	black	black	gray

Set Point in wc	.35	.35	.41

Pressure Switch Snap Ring P/N	90439850	90439850	90439850

14.7 Ignition Control

The control mounts to the heat exchanger plate. Pull out ignition cable and wiring from board, noting their positions. Release the four mounting standoffs. Refit in reverse. Ensure correct location of ignition cable and all other wiring.

14.8 Limit Switches

14.8.1 Removal and Replacement

1.Remove the electrical connections to the switch.

2.Unscrew the two screws securing the switch.

3.Fit a new switch with two screws.

4.Reconnect the electrical connections and test operation.

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Contents Combat Page Roberts-Gordon LLC Page Table of Figures Page Manpower Requirements Heater SafetyCorrosive Chemicals Installer ResponsibilityNational Standards and Applicable Codes Wall TagCritical Considerations 3.1 Basic Information Minimum Required Installation ClearancesManufactured Units Clearances to CombustiblesElectrical Supply VentilationGas Supply VentNational Standards and Applicable Codes High Altitude Temperature Rise and Pressure Drop Ranges Duct Heater Installation 5.1 GeneralAir Flow and Temperature Rise Ranges Minimum Inlet Duct LengthWall Mounting Shelf Mounting and SuspensionShelf-Mounting Methods Venting Vent InstallationChanging Vent and Air Intake Orientation United States RequirementsSeparated Combustion Heaters Models Uhdxsr 75 Standard Vented Heaters Models Uhdxr 75Unvented Operation Horizontal VentingMaximum Vent Lengths Vent MaterialReplacing an Existing Heater in a Venting System Vent and Roof Detail Standard Vented Heater Common Vertical Vent Termination Concentric Vent Box UHVK1 Unvented Installation Separated Combustion InstallationAIR Supply Building VentilationConnections GAS PipingWiring Low Voltage Thermostat with One HeaterPositioning Thermostats L2 L1 Internal Wiring DiagramFlue Blower Transformer GAS Valve Flame Sensor Electrode Ladder Wiring DiagramElectrical Connection to the Heater Begin Start-Up Before Operating the Heater Operation and MaintenancePre-Start-Up Checks Electrical ChecksEND View Check Gas Rate Pressure SwitchTurning Off the Heater External ControlsUser Instructions User InstructionsHeater Operation Lighting Instructions 11.4.1 To Turn On HeaterSimple Troubleshooting Simple Troubleshooting Burner FaultsTo Turn Heater Off Servicing Vicinity of the Heater Maintenance ChecklistVehicles and Other ObjectsGas Line and Shut-off When installed DuctworkValves Burner ObservationTroubleshooting 13.1 General Conduct start-up procedure as shown on Page 23, Section Troubleshooting For Automatic Ignition Burner SystemsTroubleshooting for Flame Supervision System Troubleshooting for Flue Blower Troubleshooting for Gas ValvesBurner Components Replacement PartsBurner Injectors Burner CompartmentIgnition Electrode and Flame Probe Top, remove the blower and mounting plate as above Flue Blower Vertical InstallationIgnition Control Limit Switches Removal and ReplacementTOP View Specifications 15.1 Dimension DataTechnical Data Table General Technical Data TablePage Roberts Gordon will not PAY for Warranty is Void ifRoberts-Gordon Limitations on Authority RepresentativesPage Owner Warranty Registration Card Page Page Clearances to Combustibles