B. Constructing the Appliance Chase
A chase is a vertical boxlike structure built to enclose the gas appliance and/or its vent system. Vertical vents that run on the outside of a building may be, but are not re- quired to be, installed inside a chase.
Construction of the chase may vary with the type of build- ing. These instructions are not substitutes for the require- ments of local building codes. Local building codes MUST be checked.
Chases should be constructed in the manner of all out- side walls of the home to prevent cold air drafting prob- lems. The chase should not break the outside building envelope in any manner.
Walls, ceiling, base plate and cantilever floor of the chase should be insulated. Vapor and air infiltration barriers should be installed in the chase as per regional codes for the rest of the home. Additionally, in regions where cold air infiltration may be an issue, the inside surfaces may be sheetrocked and taped for maximum air tightness.
To further prevent drafts, the wall shield and ceiling firestops should be caulked with high temperature caulk to seal gaps. Gas line holes and other openings should be caulked with high temp caulk or stuffed with unfaced
insulation. If the appliance is being installed on a cement slab, a layer of plywood may be placed underneath to pre- vent conducting cold up into the room.
C. Clearances
WARNING
Fire Risk.
Odor Risk.
•Install appliance on hard metal or wood surfaces extending full width and depth of appliance.
•Do NOT install appliance directly on carpeting, vinyl, tile or any combustible material other than wood.
WARNING
Fire Risk.
•Construct chase to all clearance specifications in manual.
•Locate and install appliance to all clearance
specifications in manual.
A
FROM TOP OF HOOD TO CEILING
E
B F
JH
C 
K
D 
G 
I
CLEARANCES TO COMBUSTIBLES:
| A | B | C | D | E | F | G | H | I | J | K |
| Rough | Rough | Rough | Rough | Clearance |
| Combustible | Behind | Sides of | Floor to Top | Front of |
| Opening | Opening | Opening | Opening | Combustible Floor | of Access | |||||
| (Vent Pipe) | (Height) | (Depth) | (Width) | to Ceiling |
| Flooring | Appliance | Appliance | Panel | Appliance |
|
|
|
|
|
|
| |||||
Inches | 10 | 22 | 42 | 31 | 0 | 0 | 1/2 | 1/2 | 4 | 36 | |
mm | 254 | 1137 | 559 | 1067 | 788 | 0 | 0 | 13 | 13 | 102 | 914 |
Figure 3.2 Clearances to Combustibles (Vertical Venting)
8 | Heat & Glo • |
