Atmospheric
water heater vent
requirements, testing, location, problems...
Use this article to find out how to properly vent a gas water heater
and to safely remove exhaust gases to the outside atmosphere.
Good water heater vent is important for gas appliances to operate
properly and safely remove products of combustion and water vapor out. To answer
the question; how to properly vent a gas water heater, use the checklist below which provides the answers for:
How
to properly vent a gas water heater - Location
How and where are you going to locate your gas water heater is very
important, and if the gas unit is not properly vented heating
performance
will be affected or put your health in danger.
If you don't know how to properly vent a gas water heater, consult the
local or national codes and manufacturer instructions, and keep in mind
that combustion and ventilation requirements will determine
where the unit will be located; is the area confined, unconfined or your gas water heater is located inside the small
rooms and closets.
Confined areas are considered as
areas with less than 50 cubic ft for each 1000 BTUH of the total input
for gas fired appliances. Lots of air has to be provided for water
heaters located in confined spaces or small enclosures. Two permanent
openings are needed for normal venting, one 12" of the top and one 12"
of the
bottom of that enclosure. The size of the opening is
determined by the total BTUH input of gas fired appliances inside that
room.
If the air is supplied from the adjacent room, total
volume of these
rooms has to provide enough fresh air for combustion and ventilation.
If the air is coming from the outside, it can be transferred directly or
using vertical and horizontal ducts, which should be with the same
cross-sectional area as the free area of the opening.
For an unconfined space, or
open
area, an indoor air is
used for combustion and the requirement for good venting is the minimum
of 50 cubic feet
for each 1000 BTUH of the total input of all gas-fired appliances
located there.
Water heater vent system and air supply requirements are
as described, very important so locate the heating unit as close to the
chimney and venting
system as possible. Venting system must be able to run from the water
heater to the exit
with the minimal length and elbows.
Tips on combustion air supply and
ventilation
Proper clearances from the water heater must be
maintained to allow the unobstructed air flow to the unit.
To properly vent a gas water heater, provide
openings
for air to enter and exit the area.
Openings for venting the gas heater, should be
required size, per water heating manufacturer instructions and codes.
Fresh air should not be taken from areas where the
negative pressure is, from areas where devices like exhaust fans,
furnace, dryers or fireplaces are located.
Fresh air should be free of corrosive elements and
flammable vapors. The warranty might be voided.
Venting pipe should be the same size as the openings.
Do
not block with the insulation blanket or any other obstruction the base
of the heater and draft hood, so the air can enter the heater chamber.
Is vent pipe system discharging gases safely
Ensure that there is a proper drafting at the draft hood on the top of
your tank type atmospheric water heater. If there is a problem with the
correct venting check the following:
Is the draft hood properly installed?
Is the flue baffle positioned in the flue tube?
Is the venting system correctly sized?
Is the venting pipe system done per codes and
standards?
Are all the vent connectors securely fastened and
supported properly?
Any restrictions or obstruction in the vent system?
... to learn how to properly vent a gas water heater.
How
to properly vent a gas water heater with a chimney connection
Chimney has to be clear and free of any obstructions and according to
the codes, for the proper venting products of
combustion. Chimney has to be certified for this purpose. How to properly vent a gas water heater? For
the proper connection to the chimney follow the next requirements:
Install connector above the extreme bottom of the
chimney.
The connection must be firm and sealed to prevent
the vent connector from falling out.
Do not extend vent beyond the edge of the chimney.
How
to properly vent a gas water heater with a vertical exhaust vent
Atmospheric gas water heaters with the vertical venting must be
installed with UL listed type B vent pipe and according to the
manufacturer instruction. Vent pipe must be terminated in a vertical
position with a listed cap only, and it can be combined with the
chimney as long as the proper draft is established.
How to properly vent a gas water heater? Recommendation is to follow
codes, standards, manufacturer instructions and tips provided here.
For
example, 90 degree elbow installed on the top of the water heater draft
hood can reduce the vent efficiency by 50%. This is why it is important
to allow a rise of ten vent diameters off of the top of the unit and
before the first elbow.
Inspecting the venting
system
Due to the Carbon Monoxide and fire hazard, inspect the venting system
at least once a year. This is what you should check during the
inspection and where to pay attention to properly vent a gas water
heater:
Flue gases may escape if the vent pipe is
not properly installed.
Sooted or deteriorated vent system causes the
improper venting or leakage of venting gases.
Rusty flakes at the top of the heater are sign of
the
corrosion. Acidic water vapor or condensate is the cause of the vent
rusting.
Remove the chemical substances as the vapor may lead
to corrosion of the flue.
How
to properly vent a gas water heater and test
Another tip on how to properly vent a gas water heater is to check the draft in the water heater. Let the unit run for 15 mins
put a match flame around the relief opening of the draft hood, and if
the steady flame is drawn into the opening, this indicates the proper
draft. If the flame flutters or is blown out, combustion products are
escaping.
Water heaters are equipped with the thermal switch designed to shut off
the gas supply in the event when the water heater is exposed to the
flammable vapor or due to the poor combustion caused by the blocked
vent or insufficient combustion air.
Common problems
If the heater is installed in a confined area and the
burner will not ignite or burner flame is yellow, provide fresh air
ventilation.
If the heater flue or vent system
is blocked, and there is a lack of Oxygen, here are the possible
problems you might be facing; the
burner flame is yellow and the flame is "lazy", slow hot water
recovery, combustion odor,
smoking and sooting or burner flame floats. Unblock and clean the vent
pipe.