Water Vapor: A By-Product Of Unvented Room Heaters; Air For Combustion And Ventilation - Procom Heating MD100TBA Manual De Instalación Y Funcionamiento Del Propietario

Water vapor is a by-product of gas combus-
tion. An unvented room heater produces ap-
proximately one (1) ounce (30 mL) of water for
every 1,000 BTUs (0.3 KWs) of gas input per
hour. Unvented room heaters are recommended
as supplemental heat (a room) rather than a
primary heat source (an entire house). In most
supplemental heat applications, the water vapor
does not create a problem. In most applications,
the water vapor enhances the low humidity
atmosphere experienced during cold weather.

AIR FOR COMBUSTION AND VENTILATION

WARNING: This heater shall
not be installed in a confined space
or unusually tight construction
unless provisions are provided
for adequate combustion and
ventilation air. Read the following
instructions to insure proper fresh
air for this and other fuel-burning
appliances in your home.
Today's homes are built more energy efficient
than ever. New materials, increased insulation
and new construction methods help reduce
The following are excerpts from National Fuel
Gas Code, ANSI Z223.1/NFPA 54, Air for
Combustion and Ventilation.
All spaces in homes fall into one of the three
following ventilation classifications:
The air that leaks around doors and windows may
provide enough fresh air for combustion and ven-
tilation. However, in buildings of unusually tight
construction, you must provide additional fresh air.
Unusually tight construction is defined as
construction where:
a. walls and ceilings exposed to the outside
atmosphere have a continuous water
vapor retarder with a rating of one perm
(6 x 10 kg per pa-sec-m
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openings gasketed or sealed and
b. weather stripping has been added on
openable windows and doors and
200000-01B
WATER VAPOR: A BY-PRODUCT OF
UNVENTED ROOM HEATERS
PROVIDING ADEQUATE VENTILATION
Unusually Tight Construction
) or less with
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The following steps will help ensure that water
vapor does not become a problem.
1. Be sure the heater is sized properly for the
application, including ample combustion
air and circulation air.
2. If high humidity is experienced, a dehu-
midifier may be used to help lower the
water vapor content of the air.
3. Do not use an unvented room heater as
the primary heat source.
heat loss in homes. Home owners weather
strip and caulk around windows and doors
to keep the cold air out and the warm air in.
During heating months, home owners want
their homes as airtight as possible.
While it is good to make your home energy
efficient, your home needs to breathe. Fresh
air must enter your home. All fuel-burning ap-
pliances need fresh air for proper combustion
and ventilation.
Exhaust fans, fireplaces, clothes dryers and
fuel burning appliances draw air from the house
to operate. You must provide adequate fresh
air for these appliances. This will insure proper
venting of vented fuel-burning appliances.
1. Unusually Tight Construction
2. Unconfined Space
3. Confined Space
The information on pages 7 through 9 will help
you classify your space and provide adequate
ventilation.
c. caulking or sealants are applied to areas
such as joints around window and door
frames, between sole plates and floors,
between wall-ceiling joints, between wall
panels, at penetrations for plumbing, electri-
cal and gas lines and at other openings.
If your home meets all of these three criteria,
you must provide additional fresh air. See
Ventilation Air From Outdoors, page 9.
If your home does not meet all of the three
criteria above, proceed to Determining Fresh-
Air Flow For Heater Location, page 8.
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