A.O. Smith PCG6240T403NOV 100, GAHH 40 100 GAS Control VALVE/THERMOSTAT Removal / Replacement

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GAS CONTROL VALVE/THERMOSTAT REMOVAL / REPLACEMENT

Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician.

Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, a short length of 1/2” threaded Pipe.

Removing the Gas Control Valve/Thermostat:

1.Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second. Then press the “COOLER” button to the lowest setting (Figure 112).

2.Turn gas control switch to the “OFF” position (located right side of the gas control valve/ thermostat) and turn off the gas supply to the unit (Figure 113).

3.Disconnect the electric connection by unplugging the transformer from the wall outlet (Figure 113).

4.Release water pressure by opening a nearby hot water faucet, let run until water is cool to touch. Turn off water supply to the water heater.

5.Remove the manifold cover/ outer door from the unit by depressing on the lower portion and pulling outward.

6.Connect a drain hose to the drain valve and run it to an adequate drain or to the exterior of the building. Open the water heater drain valve and allow the water to drain from the tank.

7.Unplug all the electrical connections from the bottom of the gas control valve/thermostat (Figure 114).

8.Using a 3/4” open end wrench or a crescent wrench remove the manifold tube from the gas control valve/thermostat (turning counterclockwise -natural gas). Grasp the manifold tube and push down slightly to free the manifold tube from the gas control valve/thermostat (Figure 114).

9.Using a phillips head screwdriver remove the transformer box from the front of the water heater by removing the one (1) screw at the top of the transformer box (save screw for reinstallation later) (Figure 115).

10.Disconnect the two (2) electrical flag connectors from the pressure switch, also disconnect the air pressure tubing. Using a phillips head screwdriver remove the pressure switch from the water heater’s front by removing the two (2) screws securing it (save screws for reinstallation later) (Figure 115).

Figure 112.

HOTTER COOLER

Electronic Control Display

Figure 113.

ON

OFF

ON/OFF

SWITCH

UNPLUGGED

Figure 114.

IMPORTANT:

 

 

WHEN BRUSHING ON AN

 

GAS CONTROL

APPROVED NONCORROSIVE

 

LEAK DETECTION SOLUTION,

 

VALVE/THERMOSTAT

DO NOT SPLASH SOLUTION

 

 

ONTO ELECTRICAL CON-

 

 

NECTIONS.

 

 

 

 

PRESSURE

MANIFOLD TUBE

 

SWITCH/FAN,

 

FV SENSOR

POWER SUPPLY

IGNITER/

CONNECTOR

 

TRANSFORMER

FLAME

 

CONNECTOR

SENSE

DISPLAY, ANODE

 

CONNECTOR

ROD CONNECTOR

Figure 115.

PRESSURE

SWITCH

MANIFOLD

TUBE

SCREW AT

TRANSFORMER

BOX

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Contents Models ALL Technical and Warranty Questions Service Handbook Tools Required for servicing gas modelsFire or Explosion Harzard Breathing Hazard Carbon Monoxide GasTable of Contents Basic Installation & Operation Installation of Residential GAS Water HeaterCombustion AIR and Vent System Requirements Carbon Monoxide WarningReference Vent Connectors Connector must be firmly attached Gas Control Valve/Thermostat Lower Control Know the Water HEATER’S Component PartsElectronic Control Display Upper Control Air Intake Chamber Fan Burner/Manifold Door AssemblyPressure Switch Power Anode Rod HOW the Water HEATER’S Component Parts are ConnectedWater Heater Operation Sequence of OperationFILLING, Draining and Flushing the Water Heater Tank For Your Safety Read Before Operating Lighting InstructionsAdjusting the Temperature on Electronic Control Display Hotter CoolerFault Code Retrieval Using the Electronic Control DisplayFault Code Diagnostics Reviewing Fault Codes FV-Sense Reset SequenceElectronic Control Display Troubleshooting Electronic Control DisplayControl Display Troubleshooting Control Display Status Problem SolutionLDO-SW, OPEN, and Clean Screen Troubleshooting Flowchart YESCleaning the Combustion Chamber and Air Diverter Assembly External Inspection and CleaningCleaning the Air Intake Chamber Screen Removing the Electronic Control Display Electronic Control Display Removal / ReplacementInstalling the Electronic Control Display Powered Anode ROD Removal / Replacement Removing the Powered Anode RodInstalling the Powered Anode Rod Installing the Pressure Switch Pressure Switch Removal / ReplacementRemoving the Pressure Switch Transformer Removal / Replacement Removing the TransformerInstalling the New Transformer AIR Intake Chamber BOX Removal / Replacement Removing the Air Intake Chamber BoxInstalling the Air Intake Chamber Box Installing the Fan in the Air Intake Chamber Box Wiring Harness Removal / Replacement PressureReplacing the Wiring Harness Installing the New Wiring HarnessUndue Pressure or Sudden Force AIR Intake Chamber FAN Removal / Replacement Removing the Fan from the Air Intake ChamberInstalling the Fan in the Air Intake Chamber Box Pressure Tubing Removal / Replacement Installing the Air Intake Chamber Box Inner DOOR/MANIFOLD/BURNER Assembly Removal / Replacement GAS ControlInstallation Caution Must Be Taken TABFlame SENSE/HOT Surface Igniter Removal / Replacement Replacing the Flame Sense/Hot Surface Igniter AssemblyBurner Removal / Replacement Installing New Burner Removing Old BurnerPressure Burner Orifice Removal / Replacement Installing New Burner Orifice Removing Old Burner OrificeReinstalling The Inner Door/Manifold/Burner Assembly GAS Control VALVE/THERMOSTAT Removal / Replacement Removing the Gas Control Valve/ThermostatInstalling the Gas Control Valve/Thermostat Checking the GAS Supply Pressure Checking the Gas Supply PressureGAS Water Heater Sizing Guide Leakage CheckpointsGeneral Information Formulas and ConversionsMM millimeters =Inches X