Concentric Termination Installation - A.O. Smith BTH-120 Instruction Manual

concentric termination installation

1. Concentric terminations must be ordered separately. BTH
120 - 250 models must use the 4 inch concentric termination;
Part Number: 9006328005. Contact your local distributor or
call the parts department phone number on the back cover of
this manual to order concentric terminations.
2. Determine the location for the termination.
note: roof termination is preferred since it is less susceptible
to damage, has reduced chances to intake contaminants and
vent vapors are less visible.
3. When installing a concentric termination vertically through the
roof; ensure that all exterior vertical clearance requirements
for the concentric termination, shown in Figure 30 on page
31 are being maintained. These clearances and those
cited by local and national codes must be maintained.
4. When installing a concentric termination vertically through a
flat roof, the termination's vent cap must be a minimum of 10
feet (3 m) away from any parapet, vertical wall or structure as
shown in Figure 28.
CONCENTRIC TERMINATION(S)
MUST BE A MINIMUM OF 10 FEET
(3 m) AWAY FROM ANY PARAPET,
VERTICAL WALL OR
STRUCTURE.
CONCENTRIC TERMINATION
FLAT ROOF CLEARANCE
figure 28
note: If this required 10 foot (3 m) distance to a parapet,
vertical wall or structure cannot be maintained, standard
terminations must be used. See Vertical Termination
Installation on page 27.
5. When installing a concentric termination through a sidewall;
ensure that all exterior sidewall clearance requirements for
the termination, shown in Figure 49 on page 37, are being
maintained. These clearances and those cited by local and
national codes must be maintained.
6. When installing multiple concentric terminations vertically
through a roof or horizontally through a sidewall ensure the
required clearances between terminations and groupings of
multiple terminations are maintained. See pages 32 and
33 for more information.
7. Cut a 5 inch (13 cm) diameter hole for the 4 inch concentric
termination where the termination will pass through the wall or roof.
note: Beware of concealed wiring and piping when cutting
through the wall or roof.
8. When installing multiple concentric terminations vertically
through the roof in the same location the termination caps
for all concentric terminations must be at the same height
measured from ground. See multiple Concentric Termination
Arrangements on page 33.
9. Determine if the concentric termination will need to be
shortened or lengthened to accommodate required clearances
or to ensure all vent caps are at the same height when
installing multiple terminations vertically through the roof in the
same location.
See Figure 29 on page 31 for the maximum and minimum
lengths allowed for the 4 inch concentric termination.
When extending the length of a concentric termination
do not use couplings. The use of couplings will restrict
flow through the termination and may cause improper
combustion. The termination's intake air and vent pipes must
be replaced with longer sections of the same pipe material
when extending the length of the termination.
Use only SDr-26 pipe to extend the 4 inch concentric
termination.
When shortening the length of the termination carefully
measure and cut the larger (intake air) pipe first. Cut the
same amount of pipe off of the smaller (vent) pipe.
10. Proceed to 4 Inch Concentric Termination Installation on
page 31.
30