NTI Boiler: Venting below grade and outdoor vent piping
Venting below grade and outdoor vent piping on a NTI boiler: Vent pipe that leaves the building below grade, or runs outside the wall before it terminates, has tighter limits than a normal indoor run. Before touching anything, confirm exactly which section of the vent sits outdoors and how much of it counts toward the total vent length. These limits apply to the NTI TRX150.
Applies to: Below grade and outdoor vent runs
Common causes of venting below grade and outdoor vent piping
- Vent exits the foundation below grade and ground water or soil can reach the penetration
- Long outdoor run exposed to cold, so condensate can freeze or pool in the pipe
- Unsupported or level outdoor pipe that sags and traps condensate
How to fix venting below grade and outdoor vent piping: step by step
- Excavate down to the point where the pipes exit so you can see the whole penetration.
- Seal the wall fully where the pipes pass through.
- Secure the exhaust and intake to the side of the building above grade.
- Keep all the normal termination clearances.
- Limit piping outside the building to 20 ft, and include that length in the total vent length.
- Support the outdoor pipe every 24 in.
- Slope the exhaust and intake back toward the boiler at 1/2 in per linear foot so condensate drains to the boiler.
If the unit shows an error code, look it up: NTI Boiler codes
Models
TRX085TRX110CTRX150TRX199TRX199C
Source: NTI TRX150 manual, p. 42. 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.