Rheem Water Heater Gas Control Valve Replacement — What This Part Does
The gas control valve on a Rheem tank gas water heater regulates gas flow to the burner and houses the thermostat that senses water temperature. It controls ignition, monitors flame safety, and on newer models communicates with the display panel to manage firing cycles. The valve can fail internally even when the pilot initially lights, or it may lose communication with the display and lock out the burner. Common failure modes include internal Honeywell control faults, flammable vapor sensor lockout (if equipped), and wiring or power issues that prevent the valve from receiving proper voltage on the control circuit. When the valve fails, the heater will not fire or will show a gas control fault code on the display.
Signs It Needs Replacing
- Pilot will not stay lit or igniter clicks but burner does not fire The gas valve is not opening or holding the pilot flame, even after multiple reset attempts.
- Display shows gas control fault or communication error The status indicator reports a fault between the display and the gas control valve, or a general gas control failure code.
- No hot water and the valve will not respond to temperature adjustment Turning the temperature dial has no effect and the burner never cycles on.
- Flammable vapor sensor lockout that will not clear after reset The valve has locked out due to a sensor fault and the seven-rotation reset procedure does not restore operation.
- Power is present at the valve but no burner response You verify voltage on the black wire (pin 1) and yellow wire (pin 3, when commanded), yet the valve does not open.
- Intermittent firing or burner shuts off mid-cycle without cause The heater lights but stops unexpectedly, and recycling power temporarily restores operation before the fault returns.
How to Replace It
- Turn off the gas supply at the manual gas shutoff valve upstream of the water heater.
- Shut off power to the heater (circuit breaker or disconnect switch) and close the cold-water inlet valve to the tank.
- Locate the model and serial number plate on the side of the tank and write down the full model number to cross-reference your replacement gas control valve part number.
- Disconnect the gas supply line from the inlet on the gas control valve, then disconnect the burner supply tube from the valve outlet.
- Unplug the wiring harness (Molex connector) from the gas control valve and remove any mounting bracket screws that secure the valve and thermostat assembly to the tank.
- Pull the thermostat probe from its well in the tank (you may need to gently twist and pull) and lift the entire gas control valve and thermostat assembly free.
- Install the new gas control valve by inserting the thermostat probe fully into the tank well, securing the mounting bracket, and reconnecting the wiring harness until it clicks.
- Reconnect the burner supply tube and the gas supply line to the new valve, using new flare fittings or pipe sealant as required by the connection type.
- Open the cold-water inlet valve and check for leaks around the thermostat well and all gas fittings, then open the gas shutoff valve and restore power to the heater.
- Follow the manufacturer lighting instructions to purge air from the gas line and ignite the pilot, then verify that the burner fires on a call for heat and that any display fault has cleared.
The Part You Need
| Part | Notes |
|---|---|
| Gas control valve and thermostat assembly | Amazon | Model-specific; check the model and serial plate on your Rheem water heater and match the exact part number printed on your existing gas valve or in your user manual. |
| Thermostat well gasket or O-ring (if supplied separately) | Amazon | Some valves include a new gasket for the probe; verify whether your replacement kit includes one or order it separately to prevent leaks at the well. |
Related Error Codes
If this part is failing you may also see one of these codes:
When to Call a Pro
Gas appliance work involves combustible fuel, pilot safety, and proper venting. If you are not comfortable working with gas fittings, leak-checking with soap solution, or diagnosing wiring at the valve pins, hire a licensed plumber or gas technician. A pro can also verify that the fault is truly the gas control valve and not a failed display panel, blower motor (on power-vent models), or flammable vapor sensor, which share similar symptoms. Many jurisdictions require a permit and inspection for gas-control component replacement, so check your local code before starting the repair. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.