John Wood Oil-Fired - Manual (Page 9)

Air Requirements
An adequate supply of combustion and ventilation air is
required to:
• Ensure proper combustion.
• Reduce risk of property damage, severe bodily injury or
death from possible flue gas leakage and carbon monox-
ide emissions.
Do not install an exhaust fan in the same room as the water
heater.
Satisfactory combustion cannot be sustained in an area that
is not provided with fresh air. Fresh air contains oxygen that
is necessary for proper combustion. If the water heater is
installed in a confined space, sufficient fresh air must be
drawn in from outside of the enclosure.
NOTE: Lack of adequate fresh air supply may cause a
poor flame.
Air Supply
In Canada:
If the water heater is installed in a house built to the require-
ments of the “National Building Code of Canada, 1985”,
or a subsequent edition, the space shall be provided with air
inlets as outlined below, or have a mechanical air-supply
system of sufficient equivalent capacity. If a mechanical air-
supply system is used, it shall be interlocked to the appli-
ance or equipment.
NOTE: In unconfined spaces in buildings of conventional
frame, brick, or stone construction built prior to the require-
ments of the “National Building Code of Canada, 1985”,
and not subsequently significantly air-tightened, infiltration is
normally adequate to provide air for combustion and some
ventilation; however, there may be notable exceptions.
Houses built in accordance with the “National Building
Code of Canada, 1985” (or subsequent edition), with
extensive exterior stucco coating, or with a sealed vapour
barrier or other similar air sealing technique, will often be
sufficiently airtight so that there is not sufficient air for both
combustion and venting the products of combustion of an
oil-fired appliance, or for replacing the air vented by other
exhaust devices within the house.
Outdoor Combustion & Ventilation Air
(Unconfined space)
If the water heater is installed in an unconfined space in a
building having insufficient infiltration, additional air for com-
bustion and ventilation shall be obtained from outdoors or
from spaces freely communicating with the outdoors. Under
these conditions, permanent opening(s) shall be provided
so that the total air received through these openings will be
at least as much as would be admitted by openings having
a total free area of 4.5 cm
2 /kWh (1 in 2 /5000 Btu/h) of the
total input rating of all oil-fired appliances.
Outdoor Combustion & Ventilation Air (Confined
space)
A heater installed in a confined space that obtains all of its
air for combustion and ventilation from outside the building
shall be provided with two permanent openings, one near
the top of the enclosure and another near the bottom. Each
opening shall communicate directly or by means of ducts
with the outdoors or to such spaces (such as a crawl space)
that freely communicate with the outdoors, and shall be
sized in accordance with “Air Duct Sizing”.
Outdoor Combustion Air & Indoor Ventilation
Air (Confined space)
An appliance located in a confined space that obtains its
combustion air from outdoors and ventilation air from within
the conditioned space of the building shall be provided with
two permanent openings for ventilation. One located near
the top of the enclosure and another near the bottom. Each
opening shall have a free area of not less than 19.5
cm
2 /kWh (1 in 2 /1000 Btu/h) of the total input rating of all
– 9 –
OIL
STORAGE
TANK
VENT
FILL CAP
LEVEL
GAUGE
SERVICE
SWITCH
AQUASTAT
CUT OFF VALVE
OIL FILTER
DRAFT
REGULATOR
BLOCKED VENT
SAFETY SWITCH
T&P VALVE
OPERATING
INSTRUCTIONS
OIL
BURNER
Figure 4 Installation Diagram
RISE 20mm/m
(1/4 in./ft.)
CAUTION
If an all-house ventilation fan is used, a sep-
arate outside air duct must be used and
ducted to the furnace room and/or room
where the water heater is located.