All installations and services must be performed by qualified service personnel.
The horizontal furnace installation should be on a service platform large enough to allow for proper clearances on all sides and service access to the front of the furnace (See Table 1). If the furnace is suspended, it must be supported at both ends and in the middle with clearance allowed for removal of both access doors. Gas supply line contact is only permissible between lines formed by the intersection of the top and two sides of the furnaces casing and the building joists, studs, or framing (See Figure 1).
Equipment must be installed in accordance with regulations of the National Board of Fire Underwriters and the National Fuel Gas Code. Authorities having jurisdiction should be consulted before installations are made.
C. Replacing An Existing Furnace From A Common Vent
: These furnaces may NOT be common vented with any other appliance.
D. General Requirements For Venting Models CHX3 / CDX3
The CHX3 / CDX3 furnace venting system must be installed by a qualified service person in accordance with local installation codes and these instructions. In the absence of applicable local codes, conform to the National Fuel Gas Code, NFPA 54 /ANSI
Installation shall, at least, conform to the following requirements.
1.The exhaust vent / combustion air intake terminations specified by Thermo Products, in this manual, shall be used.
2.All plastic pipe and pipe fittings sourced to complete the exhaust vent and air intake systems shall be constructed of rigid PVC (polyvinyl chloride) thermoplastic. All components shall have a wall thickness equivalent to Schedule 40 series materials.
In addition, all sourced PVC components shall be listed by a nationally recognized testing agency (e.g. NSF, UL, etc.) as conforming to one (1) or more of the following design standards.
PVC Pipe Designation | Design Standard |
Cellular Core | |
DWV | |
Schedule 40 |
3.The exhaust vent pipe and combustion air pipe shall be at least as large as the exhaust vent / air intake pipe specified by Thermo Products. Size reduction is never permissible. The required exhaust vent / air intake pipe sizes are:
•nominal
•nominal
4.The furnace model series CHX3 / CDX3 shall not be common vented with any other appliance, including those burning solid fuels.
5.All horizontal runs of exhaust vent pipe shall slope upward at least ¼ inch per foot from the outlet of the furnace (for model CHX3), or the outlet of the drain tee (for the model CDX3), to the vent termination, beyond the outside wall. This slope will permit proper drainage of the condensate.
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