Laars Pennant PNCP, Installation And Operation Instructions Manual

LAARS Heating Systems

Page 8

a Category I vent system, and includes rules and tables
to size these vent systems. If the Pennant’s vertical
vent system does not satisfy the criteria for Category I
venting, it must be vented as a Category III system.

All Pennant vent systems which discharge

horizontally (without the use of a power venter) are
considered Category III vent systems.

2.2.2 Category I Vent

When vented as a category I appliance, the vent

system must conform to the National Fuel Gas Code
(American National Standard Z223.1-Latest Edition)
in the U.S., or in Canada, to CSA B149.1 (latest
edition). The vent system must be sized and installed
for a Category I Fan-Assisted Appliance.

If chimney height is greater than 25 feet, or if

multiple units are vented into the same vertical vent, a
barometric damper must be installed on each
appliance, such that the flue draft does not exceed
(negative) 0.1" w.c.

If using a power venter for any type of Category

I venting, the draft should be set between (negative)
0.01 and 0.10" w.c.

2.2.3 Common Venting Systems

Pennant units are Category I fan-assisted when

vented vertically and adhering to all applicable codes.
Pennant units are not allowed to be vented into a
common horizontal vent system, unless a properly-
sized vent fan is used, and the common vent system is
properly designed by the vent fan manufacturer or a
qualified engineer.When common venting Pennant
fan-assisted heaters with other appliances through one
shared vertical duct called a “common vent”, special
care must be taken by the installer to ensure safe
operation. In the event that the common vent is
blocked, it is possible, especially for fan-assisted
devices, to vent backwards through non-operating
appliances sharing the vent, allowing combustion
products to infiltrate occupied spaces. If the
appliances are allowed to operate in this condition,
serious injury or death may occur.

WARNING

Operation of appliances with a blocked common
vent may lead to serious injury or death. Safety
devices must be implemented to prevent blocked
common vent operation. If safe operation of all
appliances connected to a common vent cannot be
assured, including prevention of spillage of flue
gasses into living spaces, common venting should
not be applied, and appliances should each be
vented separately.

It is for this reason that, in addition to following

proper vent sizing, construction and safety
requirements from the National Fuel Gas Code, ANSI
Z223.1 or in Canada, from CSA B149.1 as well as all

applicable local codes, it is required that installers
provide some means to prevent operation with a
blocked common vent. It is suggested that a blocked
vent safety system be employed such that if the switch
from one appliance trips due to excessive stack spill or
backpressure indicating a blocked vent condition, that
all appliances attached to the vent be locked out and
prevented from operating. (Note that the Pennant Pool
Heater is equipped with a blocked vent safety
(pressure) switch, as shipped.)  As an additional
precaution, it is recommended that a Carbon
Monoxide (CO) alarm be installed in all enclosed
spaces containing combustion appliances. If assistance
is required in determining how a blocked vent safety
system should be connected to a LAARS product,
please call Applications Engineering at (603) 335-
6300.

Refer to the installation and operating

instructions on all appliances to be common vented for
instructions, warnings, restrictions and safety
requirements. If safe operation of all appliances
connected to a common vent cannot be assured,
including prevention of spillage of flue gasses into
living spaces, common venting should not be applied,
and appliances should each be vented separately.

2.2.4 Category III Vent

When the Pennant is vented with horizontal

discharge, it must be installed per this installation
manual and the venting system manufacturer’s
installation instructions. The vent system must be
sealed stainless steel, per table 5.

Route the vent pipe to the heater as directly as

possible. Seal all joints and provide adequate hangers
as required in the venting system manufacturer’s
Installation Instructions. Horizontal portions of the
venting system must be supported to prevent sagging
and may not have any low sections that could trap
condensate. The unit must not support the weight of
the vent pipe. Horizontal runs must slope downwards
not less than ¼ inch per foot (2 cm/m) from the unit to
the vent terminal. Reference Table 2 for the size of the
Category III vent system. Up to three elbows can be
used with 50 linear feet (15.2m) of pipe. Subtract 10
allowable linear feet (3.0m) for every additional elbow
used.

Term

Description

Pipe

Must comply with UL Standard 1738

such as Type 29-4C Stainless Steel

(either insulated or non-insulated).

Joint

Follow vent manufacturer’s instructions

 Sealing

Table 5. Required Horizontal Venting Material.