Goodman Furnace: Check burner orifices
Check burner orifices on a Goodman furnace: These furnaces leave the factory with #45 natural gas orifices. You only change them for altitude derate or an LP conversion. What I run into most is an orifice somebody has damaged with the wrong tool, or one that was peened and redrilled. A dent or burr kicks the gas stream sideways, so the flame will not sit right in the burner and nothing you do with the regulator will tidy it up. If the flame looks lazy, lifts, or rolls, look at the orifices before you turn any adjustment screws.
Applies to: Main burner orifices
Common causes of check burner orifices
- Dent or burr in orifice causing gas stream deflection
- Orifice peened over and redrilled
- Orifice spud of wrong length substituted
- Orifice partly blocked by debris or rust from the gas line
How to fix check burner orifices: step by step
- Shut off all gas and electrical power
- Check the orifice visually for distortion or burrs
- Check orifice size by the number stamped on it, and compare it to what the furnace needs for fuel type and altitude
- Remove and install orifices with a box-end wrench to avoid distortion
- Never peen over and redrill an orifice
- Replace any orifice with a dent or burr
- After reassembly check for leaks with an approved method and verify flame pattern and manifold pressure
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service manual, p. 50-51. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.