Replace a Pilot Assembly (Standing Pilot)

Replace the standing-pilot burner assembly: the pilot orifice + bracket that shapes and aims the flame at the thermocouple/flame sensor. Match and clear the orifice, transfer the thermocouple/sensor, set the flame so it fully envelops the sensing tip, then light and verify the pilot holds and the main burner ignites.

Approx. 45 min

Before you start

•Confirmed standing-pilot system with a weak/yellow/lazy or missing pilot flame that won't hold the thermocouple — pointing at a plugged orifice or a damaged pilot assembly rather than the thermocouple itself.
•Rule out gas supply / inlet pressure and a partially closed pilot adjustment before condemning the assembly.
•Correct OEM pilot assembly with the right orifice size for the fuel (NG vs LP use different pilot orifices) and the matching mounting/bracket and tubing fitting.

Tools & materials

Open-end wrenches (pilot tubing + thermocouple nuts) · Pilot-orifice cleaning wire / soft brush (never drill it out) · Manometer (inlet pressure check), nut drivers + screwdrivers · Replacement OEM pilot assembly (correct fuel/orifice)

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Shut off & remove

Set the gas to OFF and disconnect the pilot
Turn the gas-valve knob to OFF, let parts cool, then disconnect the pilot gas tubing, the thermocouple lead, and any ignition/sense lead from the assembly. Note the flame aim before removing.
⚠ Gas OFF and cool before disconnecting; never check leaks with a flame later.
Unbolt the pilot bracket from the burner
Remove the pilot assembly from its bracket on the burner. Inspect the pilot tubing for debris and the orifice for soot/lint/spider nests — these are the usual reasons a pilot goes weak.

Fit the new pilot & clear the orifice

Confirm and clear the correct orifice
Verify the new assembly's pilot orifice matches the fuel (NG vs LP). If reusing/clearing an orifice, clean it with a soft cleaning wire — NEVER drill or ream it, which enlarges it and overfires the pilot.
Tools: Pilot-orifice cleaning wire / soft brush
Target: Correct orifice for the fuel; cleared with a wire, never drilled
Mount the assembly and transfer the thermocouple/sensor
Bolt the pilot assembly to the burner bracket and reconnect the pilot tubing, the thermocouple (finger-tight + ~1/4 turn, don't overtighten), and any spark/sense lead. Aim the pilot hood so the flame will wash over the thermocouple/sensor tip.
Tools: Open-end wrenches
Target: Pilot aimed so the flame envelops the thermocouple/sensor tip

Light & verify the flame

Light the pilot and check the flame envelope
Follow the lighting sequence and light the pilot. The flame must be a steady blue cone that fully envelops the top of the thermocouple/sensor tip — not yellow, lazy, lifting, or blowing past the tip. Adjust the pilot flame screw if provided.
Target: Steady blue pilot flame enveloping the sensing tip (not yellow/lifting/blowing off)
Confirm the pilot holds and the main lights
Release the knob: the pilot must stay lit (thermocouple holding the magnet), then put the system to a call and confirm the main burner carries over and lights smoothly from the pilot. Leak-check any gas joint you opened with detector/solution.
Tools: Manometer
Target: Pilot holds, main burner lights cleanly from it; zero gas leaks at opened joints
⚠ Never check the pilot tubing joint for leaks with a flame — use a detector/solution.