IMPORTANT:
○
The warm air supply duct system shall be constructed of metal in accordance with NFPA 90B, 2-1.1.
○
The plenums installed to the furnace shall be constructed of metal in accordance with NFPA 90B, 2-1.3.
Using a manometer with appropriate scale range connect testing tube between manometer and chimney
connector. End of testing tube should be inserted in chimney connector so approximately 1” (25mm) of tube
protrudes into and perpendicular to exhaust stream. This measurement shall be taken approximately 12”
(305mm) above elbow/T attached to the furnace
fl
ue. Any hole made in the chimney connector for insertion of
manometer tube shall be adequately sealed with high temp materials when testing is complete.
H3.58
CHIMNEY DRAFT GREATER THAN -0.06" W.C. (-15 Pa) MAY CAUSE AN UNCONTROLLABLE FIRE
AND DAMAGE THE FURNACE.
6.4.2 MEASURING DRAFT
6.5
CONNECTING DUCTWORK/PLENUMS BETWEEN “ADD ON” FURNACE AND
ORIGINAL FURNACE
H3.59
USE EXTREME CAUTION WHEN BUILDING PLENUM/DUCT WORK SYSTEMS SO AS NOT TO CREATE
A CONDITION WHERE HOT AIR CAN BE ENTRAPPED IN DUCT WORK, OR CREATING A REVERSE
FLOW CONDITION. WHERE HOT AIR WOULD FLOW BACKWARDS INTO THE COLD AIR RETURN
PLENUM AND DUCTING.
NEVER CONNECT THE WARM AIR SUPPLY OUTLET OF THE “ADD ON” FURNACE TO THE COLD AIR
SUPPLY OF THE CENTRAL (ORIGINAL) FURNACE. FAILURE TO COMPLY MAY RESULT IN DAMAGE
TO PROPERTY AND CREATE A FIRE HAZARD.
FOR MORE INFORMATION ON ALLOWABLE/PROHIBITED METHODS OF CONNECTING "ADD ON"
FURNACES TO A PRE EXISTING FURNACE SEE FIGURES 1 THROUGH 7 OF CAN/CSA-B366.1-M91.
W415-1506 / A / 12.04.15
43
EN