Allied Air 80G1UH2V, Installation Instructions Manual

506471-01

Page 17 of  41

Issue 1034

6. The entire length of single wall metal vent connector

shall be readily accessible for inspection, cleaning, and
replacement.

7. Single appliance venting configurations with zero lateral

lengths (Tables 3 and 4) are assumed to have no elbows
in the vent system.  For all other vent configurations,
the vent system is assumed to have two 90° elbows.
For each additional 90° elbow or equivalent (for example
two 45° elbows equal one 90° elbow) beyond two, the
maximum capacity listed in the venting table should be
reduced by 10% (0.90 x maximum listed capacity).

8. The common venting Tables (5, 6,7, and 8) were

generated using a maximum horizontal vent connector
length of 1-1/2 feet (.46 m) for each inch (25 mm) of
connector diameter as follows:

9. If the common vertical vent is offset, the maximum

common vent capacity listed in the common venting
tables should be reduced by 20%, the equivalent of two
90° elbows (0.80 x maximum common vent capacity).
The horizontal  length of  the  offset shall  not exceed
1-1/2 feet (.46 m) for each inch (25 mm) of common
vent diameter.

10. The vent pipe should be as short as possible with the

least number of elbows and angles required to complete
the job.  Route the vent connector to the vent using the
shortest possible route.

11. A vent connector shall be supported without any dips or

sags and shall slope a minimum of 1/4 inch (6.4 mm)
per linear foot (305 mm) of connector, back toward the
appliance.

12. Vent connectors shall be firmly attached to the furnace

flue collar by self drilling screws or other approved
means,except vent connectors of listed type B vent
material which shall be assembled according to the
manufacturer’s instructions.  Joints between sections
of single wall connector piping shall be fastened by
screws or other approved means.

13. When the vent connector used for Category I appliances

must be located in or pass through a crawl space, attic
or other areas which may be cold, that portion of the
vent connector shall be constructed of listed doublewall
type B vent material or material having equivalent
insulation qualities.

14. All venting pipe passing through floors, walls, and

ceilings must be installed with the listed clearance to
combustible materials and be fire stopped according to
local codes.  In absence of local codes, refer to NFGC
(2223.1 ).

15. No portion of the venting system can extend into, or

pass through any circulation air duct or plenum.

16. Vent connectors serving Category I appliances shall not

be connected to any portion of mechanical draft systems
operating under positive pressure such as Category III
or IV venting systems.

17. If vent connectors are combined prior to entering the

common vent, the maximum common vent capacity
listed in the common venting tables must be reduced by
10%, the equivalent of one 90° elbow (0.90 x maximum
common vent capacity).

18. The common vent diameter must always be at least as

large as the largest vent connector diameter.

19. In no case, shall the vent connector be sized more than

two consecutive table size diameters over the size of
the draft hood outlet or flue collar outlet.

20. Do not install a manual damper, barometric draft

regulator or flue restrictor between the furnace and the
chimney.

21. When connecting this appliance to an existing dedicated

or common venting system, you must inspect the venting
system’s general condition and look for signs of
corrosion.  The existing vent pipe size must conform to
these instructions and the provided venting tables.  If
the existing venting system does not meet these
requirements, it must be resized.

Table 2