Goodman Furnace: Pipe slope, support and transitions
Pipe slope, support and transitions on a Goodman furnace: Support horizontal vent runs every three to five feet with a 1/4 in. per foot downward slope back to the furnace so condensate drains. Avoid a horizontal transition, which creates a water trap. Do not change from 2 in. to 3 in. pipe in a horizontal run. Leave room for expansion, and secure piping well if a long run is followed by an offset under 40 in.
Applies to: Vent/flue piping
How to fix pipe slope, support and transitions: step by step
- Support horizontal vent runs every 3 to 5 ft.
- Slope horizontal runs 1/4 in. per foot back toward the furnace.
- Use a transition of no less than 45 degrees to the horizontal plane.
- Do not make a horizontal 2 in. to 3 in. transition.
- Secure piping tightly where a long run ends in an offset under 40 in.
If the unit shows an error code, look it up: Goodman Furnace codes
More commissioning tips for furnace
Source: Goodman GMVC96 service and troubleshooting manual, p. 12-13. 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.