The pilot light on a Rheem water heater can fail to stay lit for several reasons, ranging from simple user errors to faulty components. Understanding the common causes, safe relighting steps, and when to call a pro can save time and prevent gas-related hazards. This guide outlines practical diagnostics and fixes to help homeowners restore reliable hot water and extend the life of a Rheem unit.

Causes Of A Pilot Light That Won’t Stay Lit

A Rheem water heater may extinguish its pilot light due to issues with gas supply, safety devices, or ventilation. Common causes include a faulty thermocouple, a dirty or blocked orifice, drafty installation, a malfunctioning gas valve, mineral buildup, or improper venting. Sediment accumulation in the tank can also trigger overheating and tip the thermocouple into safety shutoff. Recognize patterns such as frequent re-light attempts failing quickly, or the flame appearing small and weak, which can indicate any of these problems.

Safety Precautions Before DIY

Gas appliances require careful handling. Before attempting any relighting or inspection, ensure there is no gas smell in the area. If you detect gas, leave the area and contact the gas utility or emergency services immediately. Turn off the gas supply at the heater if you can do so safely. Use proper lighting equipment and keep flammable materials away. If you are unsure at any step, contact a licensed plumber or a Rheem service technician. Do not bypass safety devices or attempt repairs beyond your comfort level.

Common Fixes You Can Try

The following steps cover safe, basic troubleshooting for a Rheem gas water heater with a standing pilot light. If your model uses electronic ignition, some steps will differ.

Relight Procedure: Turn the thermostat to the “OFF” position and wait five minutes to dissipate gas. Turn to “PILOT,” press and hold the reset knob, and light the pilot with a long match or lighter. Continue to hold the reset knob for 30 seconds after the flame appears, then release slowly. Return the thermostat to the desired setting. If the flame goes out again, proceed to check the thermocouple and gas supply.
Check The Thermocouple: A faulty or misaligned thermocouple can shut off gas to protect against ignition failures. If the thermocouple is dirty or bent away from the flame, clean or reposition it. If damage is evident, replacement is usually needed.
Clean The Pilot Orifice: A clogged pilot orifice can prevent a stable flame. Turn off gas and power, access the pilot assembly, and gently clean the orifice with a soft brush or compressed air. Do not enlarge the orifice.
Inspect The Gas Valve: A sticking or faulty gas valve can interrupt flame maintenance. If the valve is not fully open or shows signs of corrosion, do not force it. A professional should test and replace a defective valve.
Ventilation And Drafts: Ensure the area around the heater has adequate ventilation and that there are no strong drafts near the vent. Blocked or improperly vented exhaust can cause the flame to extinguish.
Sediment Buildup: Over time, sediment can settle and cause overheating. Drain and flush the tank per Rheem guidelines, typically a yearly maintenance step, to remove accumulated minerals.
Gas Supply And Pressure: Confirm the gas supply valve is fully open and that nearby appliances are not depleting gas pressure. A weak supply can cause a pilot to extinguish.

When To Call A Professional

Contact a licensed technician if the pilot will not stay lit after attempting relighting and basic troubleshooting. If you notice gas odors, sustained pilot flame instability, or any signs of corrosion, call for professional service immediately. Complex issues like a defective thermocouple wiring, gas valve replacement, or venting problems require certified expertise to ensure safety and code compliance.

Preventive Maintenance For Rheem Water Heaters

Annual Inspection: Have a professional inspect the thermocouple, gas valve, and venting system. Regular checks reduce the likelihood of sudden pilot outages.
Flushing The Tank: Flushing removes sediment buildup that can cause overheating or burner instability. Follow Rheem’s flushing procedure and use the recommended cleaning interval.
Vent Blockage Checks: Ensure the vent termination is clear of debris, snow, or nests. Improper venting can extinguish the pilot and create dangerous conditions.
Seal And Insulation: Inspect access panels and seals for leaks or wear. Proper insulation helps maintain efficient operation and stable flame behavior.
Age And Replacement: If the unit is older or frequently requires service, consider replacement with an up-to-date Rheem model that meets current efficiency and safety standards.