7
Figure 7 – Incorrect Outdoor Installation
Window
Or Grill
Indoor
Room
WRONG
highest point of the building with an approved
vent cap. The venting system should be installed
according to the latest edition of ANSI Z223.1
and/or, in Canada, CAN1-B149 requirement and
any local codes having jurisdiction.
IMPORTANT NOTE: Do not use sheet metal screws
at the snap lock joints of Type B gas vents.
2.
Do not weld or fasten the vent pipe to the heater
draft hood. The weight of the stack must not rest
on the heater. The draft hood and heater top
must be easily removable for normal heater
service and inspection.
3.
Avoid using long horizontal runs of the vent pipe,
and too many 90° elbows, reductions or
restrictions. Horizontal runs should have at least
a 1/4" rise per foot in the direction of flow. A vent
connector should be supported for the design and
weight of the material used to maintain
clearances and prevent physical damage and
separation of joints.
4.
Avoid ending heater vents near air conditioning or
air supply fans. The fans can pick up exhaust
flue products from the heater and return them
inside the building, creating a possible health
hazard. A minimum of 4 feet horizontal distance
must be maintained from electrical meters, gas
meters, and relief equipment.
5.
Always use double-wall or insulated vent pipe
(Type B or equivalent). In cold weather,
uninsulated outside vents can chill the rising flue
products, blocking the natural draft action of the
venting system. This can create a health hazard
by spilling flue products into the heater room.
6.
Avoid oversize vent piping or extremely long runs
of the pipe which may cause excessive cooling
and condensation. Rule of Thumb: The total
length of the vent, including the connector and
any offset, should not exceed 15 feet for every
inch of vent diameter. Longer total lengths
shown in venting tables are based on maximum
capacity, not condensation factors.
7.
When the installation of a draft fan is necessary
in connecting a venting system to a Natco
heater, the installation should be engineered
by competent personnel following good
engineering practices. The draft fan
supplier should be consulted for correct size.
The installation should be in accordance with the
latest edition of ANSI Z223.1 and/or, in Canada,
CAN1-B149 requirement and any local codes
having jurisdiction. When a draft fan is installed,
a suitable draft switch must be wired into the
heater control circuit at terminal designated “Field
Interlock” to prevent firing of the heater unless a
positive draft has been established.
2C. Installation of Outdoor Heaters
1.
Locate the heater to provide the minimum
clearances as listed in Table I, “Placement of
Heater”.
2.
Do not place the heater in an enclosure or wall
recess. Avoid locations where wind deflection off
structures might cause down draft. When such
wind conditions are possible, place the heater at
least three (3) feet from the structures.
3.
Never install the heater under any kind of roof
overhang. Do not place the heater below or
adjacent to any doors, windows, louvers, grills,
etc. which connect in any way with an inhabited
area of a building. This includes other structures
such as garages or utility rooms (see Figure 7 ).
4.
Although these models are AGA and CGA
designed certified for outdoor installations, such
installations are not recommended in areas
where the danger of freezing exists unless proper
precautions are taken for freeze protection.
2D. Gas Supply and Piping
Review the following instructions before proceeding
with the installation.
1.
Verify that the heater is fitted for the proper type
of gas by checking the rating plate. Natco heaters
are normally equipped to operate below a 2000
foot altitude. Heaters equipped to operate at
higher altitudes have appropriate stickers or tags
