Takagi T-KD20 Installation Manual And Owner's Manual - page 8
- 8 -
Exhaust Vent
This is a Category III appliance and must be
vented accordingly. The vent system must be
sealed air tight. All seams and joints must be
sealed with high heat resistant silicone sealant
or UL listed aluminum adhesive tape having a
minimum temperature rating of 350ºF. For best
results, a vent system should be as short and
straight as possible.
This unit requires 4”, Category III approved,
single wall stainless steel vent pipe or any
other Category III approved, non-combustible,
corrosion-resistant material. The following are
UL listed manufacturers: ProTech Systems Inc.
(FasNSeal), Flex-L Inc., Z-Flex Inc. (Z-Vent III)
and Heat-Fab Inc. (Saf-T Vent).
Follow the
vent pipe manufacturer’s instructions when
installing the vent pipe.
Do not common vent
this appliance with any other vented appliance.
The maximum length of exhaust vent piping
must not exceed 25 ft. deducting 5 ft. for each
elbow used in the venting system. Do not use
more than 3 elbows.
Diam
eter
Max.
No. of
Elbow
Max. Vertical or
Horizontal run in
Length
4”
3 Ea.
25 ft
For each elbow added, deduct 5 ft. from
max. Vent length.
No. of Elbows
Max. Vertical or
Horizontal Length
0 25
ft.
1 20
ft.
2 15
ft.
3 10
ft.
When installing the vent system, all applicable
national and local codes must be followed. If
you install thimbles, fire stops or other
protective devices and they penetrate any
combustible or noncombustible construction,
be sure to follow all applicable national and
local codes.
When the horizontal vent run exceeds 5 ft., the
following criteria must be observed:
•
Support the vent run at 3 ft intervals with
overhead hangers.
•
Slope the vent run downwards toward the
vent terminator at a rate of ¼” per foot.
Vent Termination
A sidewall vent terminator must be used when
the water heater is vented through a sidewall.
Takagi recommends the use of its part No.TK-
TV05. The vent terminator provides a means of
installing vent pipe through the building wall
and must be located in accordance with ANSI
Z223.1/NFPA 54, or in Canada with CAN/CSA-
B149.1 and local applicable codes.
Locate the vent terminator so that it cannot be
blocked by snow. Most codes require that the
terminator be at least 12 inches above grade,
but the installer may determine if it should be
higher depending on the job site condition and
applicable codes.
WARNING:
Improper installation can cause
nausea or asphyxiation, severe injury or death
from carbon monoxide and flue gases
poisoning. Improper installation will void
product warranty. For high altitude installation
above 4,500 feet, contact Takagi on how to
handle this situation.
General rules for venting the T-KD20 water
heater are:
1. Place the water heater as close as possible
to the vent terminator;
2. The vent collar of the water heater must be
fastened directly to an unobstructed vent
pipe.
3. Do not weld the vent pipe to the water
heater collar.
4. The weight of the vent stack must not rest
on the water heater.
5. The vent must be easily removable from
the top of the water heater for normal
service and inspection of the unit.
6. The water heater vent must not be
connected to any other gas appliance or
vent stack.
7. Avoid locating the water heater vent
terminator near any air intake devices or
air-conditioning units. These fans can pick
up the exhaust flue products from the water
heater and return them to the building. This
can create a health hazard.
8. Avoid using an oversized vent pipe or using
extremely long runs of the pipe.