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All installations and services must be performed by qualified service personnel.
9
D. General Requirements For Venting Models CHB1 / CDB1
The CHB1 / CDB1 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 Z223.1-1999, or latest edition thereof.
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 pipefittings sourced to complete the exhaust vent and air intake
systems shall be constructed of PVC (polyvinyl chloride) thermoplastic. All components
shall have a wall thickness equivalent to schedule 40 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
ASTM-F891
DWV (Drain-Waste-Vent) ASTM-D2665
Schedule 40
ASTM-D1785
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
2-inch diameter
, schedule 40, PVC thermoplastic pipe,
for models CHB1–50 / –75
& CDB1–50 / –75
, or
•
nominal
3-inch diameter
, schedule 40, PVC thermoplastic pipe,
for models CHB1–100 / –
125 & CDB1–100 / –125
.
4. The furnace model series CHB1 / CDB1 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 the model series CHB1), or the outlet of the drain tee (for the model series
CDB1) to the vent termination, beyond the outside wall. This slope will permit proper drainage of
the condensate.
Horizontal runs of air intake pipe shall slope downward at least ¼ inch per foot from the outlet of
the last elbow or last horizontal run, before exiting the wall, to the intake termination beyond the
outside wall. This slope will permit proper drainage of any precipitation that enters the intake pipe.
6. The exhaust vent pipe shall be supported at every joint (no more than 4-feet between supports) to
prevent pipe blockage due to condensate trapped at a local low point, or sag, in the vent system.
7. The
maximum permissible length of piping
(consisting of a combination of straight pipe and a
corresponding number of elbows) permitted is:
•
75 equivalent feet,
for the
exhaust vent system,
and
•
70 equivalent feet,
for the
combustion air intake system.