U.S. Boiler Company INDEPENDENCE IN3PV, Installation & Operating Manual

13

Figure 8C:  U.S. Boiler Company Gasket-Less 

Female and Gasketed Male Vent Joint Detail

2.  Procedure for joining the female end of U.S. Boiler 

Company Gasket-Less Vent with the male end of 

U.S. Boiler Company Gasketed Vent.  See Figure 

8C.

a.  Clean joints of pipe or fittings using an alcohol 

pad to remove any dirt and grease.

b.  Slip a locking band over female (bell) end of 

pipe/fitting.

c.  Apply a continuous ¼ inch bead of sealant 

around male end of joint no more than 1/8 inch 

from end.

d.  Align weld seams in pipes and use a slight 

twisting motion to FULLY insert male end into 

female end of joint.

e.  Smooth sealant around joint for a continuous 

seal.  Reapply sealant if necessary.

f.  Slip the locking band over joint and align closest 

bead in locking band with bead in male end of 

pipe.

g.  Tighten locking band by HAND with a 5/16" nut 

driver until snug plus ¼ turn.  DO NOT 

SECURE JOINTS WITH SHEET METAL 

SCREWS OR POP RIVETS.  DO NOT 

PUNCTURE THE VENT SYSTEM!

h.  Once the installation is complete, operate boiler 

and inspect all joints to ensure that flue gases 

and/or liquid condensate will not escape.

G.

  Horizontal (Through Wall) Vent Installation.

1.  Recommended Installation:  Maintain minimum ¼ 

inch per foot slope in horizontal runs. Slope toward 

vent terminal.  Position weld seams in vent pipes in 

all horizontal runs at the top to avoid condensate 

from lying on the seams.  See Figure 9.

2.  Alternate Installation:  Maintain minimum ¼ inch 

per foot slope in horizontal runs.  Slope toward 

boiler.  Install a horizontal condensate drain tee after 

first elbow.  Position seams in vent pipes in 

horizontal runs at top to avoid condensate from 

lying on the seams.

Figure 9: Horizontal Vent Installation

V. Venting (continued)

CAUTION

Moisture and ice may form on surfaces around 

vent terminal. To prevent deterioration, surfaces 

should be in good repair (sealed, painted etc.)

3.  Vent terminal location restricted per following: 

a.  Minimum 12 inches above grade or normally 

expected snow accumulation level, or 7 feet 

above grade if located adjacent to public 

walkway. Do not install over public walkway 

where local experience indicates condensate or 

vapor from Category III appliances creates a 

nuisance or hazard .

b.  Minimum 3 feet above any forced air inlet 

located within 10 feet.

c.  Minimum 4 feet below, 4 feet horizontally from, 

or 1 foot above any door, window, or gravity air 

inlet.

d.  Minimum 4 feet horizontally from electric 

meters, gas meters, regulators, and relief valves.

e.  Minimum 12 inches from overhang or corner.

4.  Use single wall thimble when passing through 

combustible outside wall (thimble use optional for 

noncombustible wall). Insert thimble through wall 

from outside. Secure outside flange to wall with 

nails or screws, and seal with adhesive material. 

Install inside flange to inside wall, secure with nails 

or screws, and seal with adhesive material.

5.  For noncombustible wall when thimble is not used, 

size opening such that female (bell) end with 

locking band attached cannot pass through.

6.  Join vent terminal to vent pipe. Locate vent pipe 

such that bell/locking band is flush with outside wall 

(or outside flange of thimble, if used) when joined to 

inside vent piping. See Figure 10.

7.  Insert vent pipe through thimble/opening from 

outside and join to vent system. Apply sealant 

between vent pipe and opening/thimble to provide 

weathertight seal.