E8
Rheem Gas Valve / Gas Supply Fault

Boiler displays E8 and locks out, often after several failed ignition attempts

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Closed or partially closed gas shutoff valve, Incorrect gas type or pressure, Failed gas valve coil, Faulty gas valve control circuit on main PCB

How to Fix / Troubleshooting

Safety first: Turn off power and close the gas shutoff valve before servicing. Gas work must comply with local codes.

  • Step 1 – Confirm gas supply: Ensure the manual gas valve to the Rheem boiler is fully open. Check that other gas appliances operate normally.
  • Step 2 – Visual inspection: Inspect the gas valve and piping for signs of damage, corrosion, or leaks (use an approved leak detection solution, never an open flame).
  • Step 3 – Reset and observe: Restore power and gas, then reset the boiler. Listen for the fan starting and the click of the gas valve opening. If there is no click and no flame, suspect the valve or control.
  • Step 4 – Professional testing: A qualified technician should measure inlet and manifold gas pressures and check the gas valve coil resistance. If the valve does not open with proper control voltage, replace the gas valve with the correct Rheem part.
  • Step 5 – Verify combustion: After valve replacement, a combustion analysis must be performed to ensure safe and efficient operation.

Warning: Do not attempt to adjust internal gas valve regulators or orifices without proper training and equipment. Incorrect settings can cause dangerous combustion.

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Repair Difficulty

Professional Required 5/5

Required Part

Gas Valve
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