IFGC 503.6.5
What it means on the job
Single-wall vent connectors must slope upward at least 1/4" per foot toward the chimney or vent terminal. Downward slope traps condensate and prevents proper draft.
Tested in 1 CraftIQ puzzle
- whats-wrongResidential Furnace Setup
Related IFGC sections
IFGC 404.3
Gas piping must not be installed in or through any air duct, clothes chute, chimney, vent, dumbwaiter, or elevator shaft. A leak inside a duct would distribute gas throughout the building.
IFGC 408.4
Gas piping to equipment must have a sediment trap (drip leg) to catch moisture and debris before it enters the gas valve. Prevents valve damage and unsafe operation.
IFGC 408.4 / IPC 1212.7
A sediment trap (drip leg) must be installed as close as practical to the appliance inlet and ahead of the gas valve. It captures moisture and debris that could damage the gas valve.
IFGC Section 304.6.1 and 304.6.2 (Outdoor combustion air)
The free AREA is what fails here, not the opening count — and that distinction matters in front of an inspector. IFGC 304.6 permits outdoor combustion air by EITHER method: 304.6.2 (One-permanent-opening) allows a SINGLE opening near the enclosure top at 1 in² per 3,000 Btu/h given 1 in. side/back and 6 in. front appliance clearances, which for 2,000,000 Btu/h needs 667 in². 304.6.1 (Two-permanent-openings) uses one opening within 12 in. of the top and one within 12 in. of the bottom, each at 1 in² per 4,000 Btu/h = 500 in² (or 1 in² per 2,000 Btu/h = 1,000 in² each if horizontal ducts are used). The 144 in² provided fails every one of those paths by a wide margin. Note these are FREE areas — per IFGC 304.10 louver and grille blockage is deducted, so the gross wall opening is larger still. So "only one opening" is NOT by itself a violation; the undersizing is.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.