Goodman Furnace: Direct vent (dual pipe) termination
Direct vent (dual pipe) termination on a Goodman furnace: On a direct vent install, what I always check first is that the intake and the vent end up in the same pressure zone. If they do not, the pressure switch will trip on windy days and you get a no-heat call that is hard to pin down. Direct vent can exit through a side wall or the roof, or run in an unused chimney with at least 12 in. above the chimney top. Take care sealing every penetration, because moisture and air leaks cause problems later.
Applies to: Direct vent installations
Common causes of direct vent (dual pipe) termination
- Intake and vent in different pressure zones, causing pressure switch trips in wind
- Major obstacle between the two terminations
- Unsealed wall penetration leaking air and water
- Gap in the chimney left unsealed
How to fix direct vent (dual pipe) termination: step by step
- Terminate both pipes in the same pressure zone: same side of roof, and no major obstacles between them.
- For a wall penetration, use a coupling on each side of the wall joined by a short pipe, sized to the wall thickness plus socket depth.
- Seal the wall penetration with silicone caulk.
- Seal the chimney gap with weather-tight, corrosion-resistant flashing.
- Check all joints for leaks after assembly.
- Run the furnace and confirm the pressure switch stays closed during heat.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service and troubleshooting manual, p. 16. 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.