How to Clean a Lazy Propane Space Heater Pilot Flame: A Comprehensive Guide

If your propane space heater’s pilot flame is burning lazily or struggling to stay lit, it’s time to take action. A properly functioning pilot flame is crucial for the safe and efficient operation of your heater. In this comprehensive guide, we’ll walk you through the step-by-step process of cleaning a lazy propane space heater pilot flame, ensuring your heater runs smoothly and safely.

Pilot Orifice Cleaning

The pilot orifice is a small opening that allows the gas to flow to the pilot light. Over time, this orifice can become clogged with dust, debris, or even spider webs, leading to a weak or inconsistent pilot flame. To clean the pilot orifice:

  1. Locate the pilot assembly and remove it from the heater by unscrewing it.
  2. Use a small wire or a reamer tool to carefully clean the orifice. Be cautious not to enlarge the opening, as this can affect the gas flow and cause safety issues.
  3. Blow out any remaining debris using compressed air.
  4. Inspect the orifice for any signs of damage or wear. If the orifice is severely damaged, it may need to be replaced.

Oxygen Intake Slot Cleaning

how to clean a lazy propane space heater pilot flame

The oxygen intake slot is responsible for allowing air to mix with the gas, ensuring proper combustion. When this slot becomes clogged, it can restrict airflow and result in a lazy pilot flame. To clean the oxygen intake slot:

  1. Locate the oxygen intake slot, which is typically near the pilot assembly.
  2. Use a small wire or a reamer tool to carefully clean the slot, taking care not to enlarge the opening.
  3. Blow out any remaining debris using compressed air.
  4. Ensure the slot is free of obstructions and allows for adequate airflow.

Thermocouple Inspection and Cleaning

The thermocouple is a safety device that generates a small electrical current when heated by the pilot flame. This current keeps the gas valve open, allowing the main burner to ignite. If the thermocouple is dirty or damaged, it may not generate enough current to keep the gas valve open, causing the pilot flame to extinguish. To inspect and clean the thermocouple:

  1. Locate the thermocouple, which is typically positioned near the pilot assembly.
  2. Use an old toothbrush or a soft cloth to gently clean the thermocouple, removing any soot, dust, or debris.
  3. Inspect the thermocouple for any signs of damage, such as cracks, bends, or corrosion. If the thermocouple is damaged, it will need to be replaced.

Reassembly and Testing

  1. Once you have cleaned the pilot orifice, oxygen intake slot, and thermocouple, reassemble the pilot assembly and reattach it to the heater.
  2. Turn on the gas supply and light the pilot flame.
  3. Observe the pilot flame to ensure it is burning steadily and consistently. Adjust the flame height if necessary, following the manufacturer’s instructions.
  4. Use a gas leak detector to check for any gas leaks around the pilot assembly and other connections.

Technical Specifications

  • Pilot Orifice Size: For propane space heaters, the typical pilot orifice size ranges from 0.016 to 0.036 inches in diameter.
  • Oxygen Intake Slot Size: The size of the oxygen intake slot varies depending on the burner design and gas type. The slot should be large enough to allow sufficient airflow for combustion but small enough to prevent flashback.
  • Thermocouple Type: The most common type of thermocouple used in propane space heaters is the copper-constantan thermocouple, which generates a voltage of approximately 25 to 30 millivolts per degree Celsius.
  • Gas Pressure: For propane space heaters, the recommended gas pressure range is typically 11 to 14 inches of water column.

DIY Cleaning Considerations

Cleaning a lazy propane space heater pilot flame can be a DIY project, but it’s essential to use the right tools and techniques to avoid damaging the components and creating safety hazards. If you’re not comfortable performing this task yourself, it’s best to hire a professional HVAC technician to service your heater.


  1. Heater Help.. Pilot Light | The Garage Journal
  2. How to clean Pilot Light that wont light / stay lit – YouTube
  3. Pilot light – HVAC-Talk
  4. Cleaning a vent free gas heater pilot light – YouTube
  5. Why bother adjusting pilot? – Heating Help: The Wall