lp-441 Rev. 002 Rel. 008 Date 8.23.18
23
2. Venting Through an Existing System
This heater may be vented through an existing unused vent system.
The inner diameter of the existing vent system is utilized for the
combustion air source. Two methods have been approved for
such venting: Concentric Venting Through an Existing System and
Venting as a Chase.
Vent / Air Inlet Size
Minimum Existing Vent / Chase Size
2”
4”
3”
5”
4”
7”
Table 10 - Minimum Existing Vent / Chase Sizing
Do not install the heater into a common existing vent with
any other appliance. This will cause flue gas spillage or heater
malfunction, resulting in substantial property damage, serious
personal injury, or death.
Contractors must check state and local codes before installing
through an existing vent opening. State and local codes always
take precedence over manufacturer’s instructions. Failure to
check state and local codes before installing through an existing
opening could result in property damage and add significantly to
installation costs.
If an existing venting system is converted for use with this heater,
the installer must ensure that the existing venting system is clean
and free from particulate contamination that could damage the
heater. Failure to do so could result in property damage and
heater failure. Such failure IS NOT covered under warranty.
Concentric Venting Through an Existing System
NOTE: The following instructions refer only to venting through an
existing vent system, and not to venting with HTP’s optional concentric
vent kits. Refer to Concentric Vent Kit installation manual (LP-166) for
further information on venting with the optional concentric vent kits.
Concentric venting through an existing system must run vertically
through the roof. See Table 10 for proper minimum vent sizing. Use
only the approved venting materials specified in Table 5 for piping the
system. All instructions listed in this Venting section apply. See Figures
12-1 and 12-2 for venting demonstrations.
SEAL
SEALED
EXISTING
EXHAUST
CAP
(w/SCREEN)
SEAL
AIR INTAKE
SEAL
LP-325-LL
03/15/12
Exhaust
In
take
Concentric Venting through an Existing System
1
12" MIN.
LP-325-MM
03/15/12
EXHAUST
SEAL
w/SCREEN
EXISTING
AIR INTAKE
SEALED CAP
COMBUSTION AIR
COMBUSTION
AIR
SEAL
Concentric Venting through an Existing System
2
In
take
Exhaust
Exhaust
In
take
07/22/13
LP-325-NN
INTAKE
EXHAUST
24"
SEAL
EXISTING
VENT
CAP
SEAL
Exhaust
In
take
Chase Venting through an Existing System
3
Figure 12 - 1, 2 - Concentric Venting Through an Existing System, 3, Chase Venting Through an Existing System
NOTE:
These drawings are meant to demonstrate system venting only. The installer is responsible for all equipment and detailing required
by local codes.
The upper and lower vent terminations as well as all joints in
the venting system must be properly sealed to ensure that all
combustion air is drawn properly and exhaust does not leak from
the system. Failure to properly seal the venting system will result in
property damage, serious personal injury, or death.
Chase Venting Through an Existing System
When venting as a chase, follow all instructions included in this
Venting section, including those in the previous Concentric Venting
Through an Existing System section. See Figure 12-3 for chase venting
demonstration.
