Resideo Q3450C1185/U Pilot Burner, Natural Gas, BCR-18 Orifice, Left Single Tip, C-Style Mounting Bracket and Primary Aeration

Pilot burner from Resideo (Honeywell Home), part number Q3450C1185/U, left single-tip style, supplied with BCR-18 orifice.

The pilot burner holds the small standing flame that lights the main burner and keeps the thermocouple hot. It is a part that does not fail so much as it clogs — lint, rust scale and spider webs in the pilot tube are the classic cause of a furnace that will not stay lit.

The left tip orientation aims the flame at the main burner. Tip direction is not cosmetic: a pilot aimed wrong lights late, heats the thermocouple poorly, or fails to carry over to the burner at all.

The orifice sets the pilot gas rate and is specific to the fuel. Fitting a natural gas orifice on propane gives a pilot that soots and lifts; the reverse gives one too small to hold the thermocouple hot.

Pilot assemblies are sized and aimed for the appliance they were built for, and the catalogue is full of parts that look alike across the bench. Bracket geometry, tube length, tip direction and orifice all have to line up, which is why the part number on the old assembly is worth more than a visual match.

When a pilot problem turns out not to be the burner, it is nearly always upstream of it: a blocked or kinked pilot tube, a thermocouple that no longer makes millivolts, or a draft condition pulling the flame off the thermocouple tip. Replace the assembly, but check the tube and the draft while it is apart.

• Brand: Resideo (Honeywell Home)
• Manufacturer Part #: Q3450C1185/U
• Type: Pilot burner
• Tip style: Left
• Orifice: BCR-18
• UPC: 085267306454
• Category: Pilot Burners