6
L o c h i n v a r
D E S I G N E R
’
S
G U I D E
E F F I C I E N C Y
+
B O I L E R
6 1 5 - 8 8 9 - 8 9 0 0
The efficiency of this appliance allows its
products of combustion to be vented through
a smaller vent pipe when compared to units
of the same Btu/hr capacity. For this reason,
resizing common venting systems is
recommended for proper operation.
When resizing any portion of the common
venting system, it should be resized to
approach the minimum size as determined
using the appropriate tables (FAN column) in
the
National Fuel Gas Code.
Failure to resize a common venting system
could lead to the formation of condensate
and premature deterioration of the vent
material.
Flue gas condensate can freeze on exterior
walls or on the vent cap. Frozen condensate
on the vent cap can result in a blocked flue
condition. Some discoloration to exterior
building surfaces can be expected. Adjacent
brick or masonry surfaces should be
protected with a rust resistant sheet metal
plate.
Vent connectors serving appliances vented by
natural draft
must
not be connected to
any portion of a mechanical draft system
operating under positive pressure.
Connection to a positive pressure stack may
cause flue products to be discharged into the
living space causing serious health injury.
Locate units as close as possible to a chimney
or gas vent.
Vent Terminations
When locating the vent cap, consider the effects
of snow, leaf dropping, etc., to ensure that no
blockage occurs.
The distance of the vent terminal from adjacent
public walkways, adjacent buildings, windows
that open and building openings
must
comply
with the latest edition of the
National Fuel Gas
Code, ANSI Z223.1.
The vent terminal
must
be vertical and
exhaust outside the building at least 2 feet
(0.6m) above the highest point of the roof
within a 10 foot (3.0m) radius of the
termination.
The vertical termination
must
be a minimum
of 3 feet (0.9m) above the point of exit in the
rooftop.
A vertical termination less than 10 feet (3.0m)
from a parapet wall shall be a minimum of 2
feet (0.6m) higher than the parapet wall.
The vent cap shall terminate at least 3 feet
(0.9m) above any forced air inlet within 10
feet (3.05m). The vent shall terminate at least
4 feet (1.2m) below, 4 feet (1.2m)
horizontally from or 1 foot (0.30m) above
any door, window, or gravity air inlet to the
building.
Do not terminate the vent in a
window well, stairwell, alcove,
courtyard, or other recessed area.
The vent cannot terminate below
grade.
Lochinvar
IMPORTANT!
The vent cap should
have a minimum
clearance of 4 feet
horizontally from electric
meters, gas meters,
regulators, air inlets and
air relief equipment.
Additionally, the vent
cap should never be
located above or below
these items, unless a 4
foot horizontal distance
is maintained.
NOTE:
The weight of the
venting system MUST
NOT rest on the boiler.
It should be properly
supported.
WARNING
Vent connectors serving
gas appliances, which
operate under a
negative vent pressure,
shall not be connected
into any portion of
mechanical draft
systems operating under
positive vent pressure.
