HVAC Procedure and Performance Guide

TASK: Install gas or all-fuel furnace vent

Training for this procedure can be found in these courses:

                         161 – Boilers l  and  131 – Oil Heat l


Gas or all-fuel furnace vent must be installed according to furnace manufacturer’s specifications, job specifications and codes.  All materials must be code approved.  Vent must conduct all combustion gasses and dilution air to outside and must pose no hazard to adjacent combustible materials.  Applicable safety procedures must be followed. (Note: Vent pipe must extend to code-specified distance above roofline).


  1. Review manufacturer’s specifications, job specifications and codes.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Determine location for vent passage to outside.  (Note:  Location must be selected to keep horizontal run of vent to a minimum.  Horizontal vent must pitch back toward furnace.  There must be adequate clearance between vent and adjacent combustible surfaces).
  5. Determine size requirements for vent based upon furnace performance data.
  6. Prepare opening.
  7. Install wall thimble, base support, roof boot or storm collar and support brackets according to manufacturer’s instructions as applicable.
  8. Install draft hood on gas furnace or draft damper on other-fuel furnace.
  9. Install automatic damper as specified on draft-hood outlet.
  10. Run vent pipe from damper or draft-hood outlet through penetration fitting.
  11. Install appropriate vent cap.
  12. Place system in operation.
  13. If equipment does not operate to specifications, troubleshoot and make required adjustments and repairs.
  14. Leave equipment in required operating status.
  15. Remove safety and protective equipment and apparel.
  16. Gather tools, equipment and leftover materials and leave work site clean.