Hearthstone
Quality
Home
Heating
Products ,
Inc.
ODEL
8521
Sterling
“G”
B-Vent
8
V
ENTING
/C
HIMNEY
R
EQUIREMENTS
Normally Aspirated Chimneys
The Sterling is a high efficiency gas heater. With
operating efficiencies as high as 80%, most heat
output is retained within the living space, with
minimal heat leaving the room via the chimney.
However, some heat is required in all chimneys in
order to establish and maintain a draft. Since most
of the heat is retained in the living space with
minimal heat entering the chimney, it is imperative
that the chimney/venting system be properly sized
and installed in order to establish and maintain the
draft required for the unit to function.
The Sterling must be properly connected to a 4"
(102-mm) diameter type B-1 vent which is
constructed and installed in accordance with
NFPA54 and NFPA211. Single wall vent pipe may
be used within the same room as the Sterling so
long as adequate (6" or 152 mm) clearance is
maintained from the single wall pipe to combustible
surfaces. The single wall vent pipe must connect to
double-wall type B-1 vent at the first wall or ceiling
penetration, and continue with type B-1 vent from
thereon. The minimum clearance from type B-1 vent
to combustibles is 1" (25-mm).
Connect the single wall vent pipe or the B-1 vent
to the flue collar located on the rear surface of the
unit using 3 sheet metal screws. For wall, roof or
partition penetration, refer to the current edition of
ANSI Z223.1 or CAN1-B149 for instructions and
clearances to combustibles. The Sterling can be
connected to an existing, properly constructed
masonry or prefabricated chimney so long as the
type B-1 vent is extended through the entire length
of the chimney. An annual inspection is required to
confirm that the vent is unobstructed. The venting
can not be connected to a flue serving a solid fuel
appliance. It can however, be connected to a flue
serving another gas or oil appliance, so long that it is
in compliance with the National Fuel Gas Code.
Type B-1 vent pipe is intended primarily for
installation inside buildings to provide an essentially
vertical passageway for flue gases from the vented
gas appliance to the outside air. When it is
impractical to install B-1 vent pipe inside a building,
it may be installed outdoors provided that it is: 1)
certified for outside installation, 2) installed in
accordance with the manufacturer's installation
instructions and 3) adequately chased (enclosed)
and insulated (per Venting Tables, Category I -
Central Furnaces, AGA and GAMA. July 1991;
Standards for Gas Vents, National Standards of
Canada; and CAN/CGA-B149.1-M91). Exterior B-1
venting not chased and insulated below the roof line
may experience continuous condensation depending
on the locality. B-1 vent pipe passing through an
unused masonry chimney flue is not considered to
be exposed to the outdoors.
Four inch flexible pipe can be used in place of
Type B-1 vent pipe wherever it is impractical or
impossible to install rigid Type B-1 vent pipe.
However, flexible pipe is less desirable than B-1
vent pipe, because there is a greater heat loss along
the length of flex pipe which may result in a reduced
or unacceptable draft.
Draft Hood/Down Draft Sensor/Spill
Switch
The Sterling has a draft hood as part of its rear
assembly. The draft hood must not be altered or
obstructed. The Sterling must be installed so that
the draft hood is in the same atmospheric pressure
zone as the combustible air inlet for the unit. The
Sterling cannot and must not be connected to an
outside air source; the unit must take its combustion
air from the living space in which it is installed.
The draft hood is equipped with a safety shutoff
down draft sensor switch (spill switch) which is
located in the draft hood just beneath the flue collar
on the rear of the unit. This switch is designed to
sense a loss of draft within the chimney. The down
draft sensor switch is wired in series with the pilot
thermocouple and is typically in the closed position.
Should the Sterling fail to establish or lose its
draft while in operation, hot exhaust gasses will spill
into the room through the bottom of the draft hood
instead of exiting the draft hood via the flue collar
and venting to the outdoors. When this undesirable
down draft condition occurs the hot gasses spilling
out of the draft hood will heat the spill switch causing
it to open which turns the unit off.
Do not modify, disconnect or otherwise defeat the
purpose of the down draft sensor switch. If your
stove shuts off during normal operation, it is
indicative of an unsafe venting condition which must
be corrected. Operation of this unit when not
properly connected to a properly installed and
maintained venting system or tampering with the
vent safety shutoff system can result in carbon
monoxide (CO) poisoning and possible death.
Power Venting
For applications where it is impractical or
impossible to extend B-1 vent pipe to above the
existing roof line, the Sterling can be vented using a
power vent. A power vent is essentially a
specialized electric fan mounted on the outer wall of
the building which is connected to the heater via flue
pipe. When the thermostat calls for heat, the power
vent turns on and creates a draft in the flue pipe
similar to the draft created by a properly functioning
conventional chimney. The Sterling then operates in
a normal fashion, satisfied by the simulated draft. A
series of interlocking safety devices prevents
operation of the heater unless the power vent is
operating properly. Both the Sterling and the power
vent are controlled by the wall thermostat and
neither will operate if there is a power failure. For
installations requiring power venting,
use only an
AGA (U.S.) or CGA (Canada) listed unit.
The power
vent supplier will in turn supply the power vent
installation instructions.
