180305 Suburban Bruner Orifice (METRIC THREADS) #55

Fits SF‑20 / SF‑20F (Above Serial 021206467) and SF/SFVH‑20Q/FQ Furnaces

The Suburban 180305 Burner Orifice meters the correct LP gas flow into the burner tube on 20k BTU Suburban furnaces. Sized at #55, this orifice is calibrated for the SF‑20 family’s BTU output and ensures proper ignition, stable flame shape, and clean combustion. The metric thread design is used on later‑production furnaces and all Q/FQ variants.

Using the correct thread type is critical—installing a standard‑thread orifice in a metric burner assembly can cause gas leaks, cross‑threading, or improper seating.

Key Features

• OEM Suburban #55 LP burner orifice

• Metric threads for late‑production SF‑20 platforms

• Provides correct gas flow for 20k BTU furnace families

• Ensures proper flame shape, ignition reliability, and combustion stability

• Brass construction for clean, consistent metering

• Direct‑fit replacement for metric‑thread burner assemblies

When Technicians Replace This Orifice

• Yellow, lazy, or unstable flame

• Soot buildup in burner or exhaust

• Furnace failing to ignite or lighting inconsistently

• Incorrect BTU output or weak heating

• Orifice clogged with debris or contamination

• Burner assembly updated to metric‑thread spec

Compatibility

SF‑Series Furnaces:

• SF‑20 (units above serial no. 021206467)

• SF‑20F (units above serial no. 021206467)

• SF‑20Q

• SF‑20FQ

SFVH‑Series Furnaces:

• SFVH‑20Q

• SFVH‑20FQ

This is the correct OEM metric‑thread #55 orifice for all models listed above.