Gas fireplace logs are becoming quite popular. Their
convenience and cleanliness have convinced many wood burners to retire the
chainsaw and log splitter. Gas logs may be fueled by either natural or propane
gas. There are two basic types of gas logs currently on the market. The two types
are the "vented" and the "vent-free."
Vented Gas Logs
Vented gas logs offer the aesthetic beauty of a wood burning
fire with the convenience of gas! The heat output from vented gas logs is
slightly better than the heat output from a regular wood fire in the same
fireplace. This is because the logs are made from a dense refractory material
that radiates heat after it warms up. Vented gas logs closely resemble the look
of a wood fire without the ash, dust or wood chips and you won’t have to run out
to the wood pile in the cold.
Vented
gas logs primarily produce a yellow flame which is attractive and natural.
However, these yellow flames are not as hot or efficient as a typical blue gas
flame. Yellow flames also contain soot and the use of vented gas logs does not
eliminate the need for chimney cleaning. Since vented gas logs produce soot, a
little smoke and possibly carbon monoxide (just like a real wood fire) your
fireplace damper must be fully open when using your vented gas logs.
Additionally, since vented gas logs produce soot the use of blowers is not
recommended as we have seen many cases where soot was blown into the house by the
blower. Manufacturers require that the damper be blocked open and the city
inspector checks this during the inspection. Since the damper is always open,
glass fireplace enclosures are recommended for fireplaces with vented gas logs.
Glass doors should always be fully open when the gas logs are burned.
Vented gas logs should only be installed in
operable wood burning fireplaces. If your fireplace doesn’t draw well when
burning wood there is no guarantee that it will work with a gas log. In short, a
gas log is not a cure-all for an ailing fireplace. When installing gas logs in a
factory-built fireplace check to see that the fireplace is approved for the
installation of vented gas logs (most are).
In summary, purchase vented gas logs for convenience, for
their beauty and realistic look, and for that warm feeling we all love! Don’t
purchase vented gas logs for a secondary heat source as you will likely be
disappointed.
Back to Top
Ventfree Gas Logs
Also referred to as "unvented", "non-vented" or
"ventless". This type of log burns with a clean, hot blue flame characteristic of
other gas appliances (furnace, range, etc.). The ventfree log is intended for
those people who wish to supplement their heating system. These logs are
generally not as attractive as vented logs, but produce much more heat. The
ventfree gas log is so clean burning that the fireplace may be operated with the
damper fully closed, forcing all of the heat out into the room. Blower systems
may be used with some ventfree logs, when they have been tested for use with the
specific model log set. The use of a blower not approved for a particular log set
may disrupt the burner flame pattern and cause sooting.
Ventfree gaslogs are limited to a maximum BTU input of
40,000 BTU. All ventfree gaslogs must have an oxygen depletion sensor (ODS) which
shuts the gaslogs off when the oxygen level in the room falls to 18% (normal
oxygen level is 21%). Most ventfree installations will require use of a hood over
the fireplace opening. This is because with a ventfree logset all of the heat is
forced out of the fireplace opening and mantles tend to get very hot unless
protected by a hood. Each ventfree gas log manufacturer will state the required
clearance from the fireplace opening to the mantle or trim above the fireplace.
Even when the minimum recommended clearance is met, the mantle may still get warm
and require the installation of a hood. Keep an eye on this if you purchase
ventfree gas logs.
Most vent-free
appliances are not approved for use in bedrooms or bathrooms. When approved, the
BTU rating must be limited to 10,000 BTU’s for bedroom use and 6,000 BTU’s for
bathroom use.
Ventfree logs may be
installed in existing masonry fireplaces or in special ventfree fireboxes that
resemble pre-fab fireplaces without a chimney connection. The use of ventfree gas
logs in factory built (pre-fab) fireplaces is hotly debated within the hearth
products industry. One manufacturer (Heatilator) has stated that they do not want
any ventfree gas logs installed in their fireplaces. (We have a copy of this
notice in our office if you would like to review it.) There is also a code change
pending that would prohibit ventfree gas logs in all factory built fireplaces
unless the fireplace has been specifically tested and approved for the use of
ventfree gas logs. This is only a pending change at this time and would not be
retroactive to existing installations even when it is added to the code. The
issue in a nutshell is this: Factory built fireplaces were designed and tested to
operate with the damper in the open position, when ventfree gaslogs are installed
and the fireplace is operated with the damper in the closed position the
temperatures at the top of the fireplace may exceed safe levels. Heatilator’s
testing of their fireplaces has shown that temperatures do exceed the safe levels
established by the test standard when the fireplace is operated with the damper
closed.
We are often asked about odor
problems associated with ventfree gas logs. Odors may be caused by airborne
contaminants or chemicals being drawn into the burner and altered by the
combustion process. Odors are not a problem as long as the burner has ample
fresh, clean air. If you have a ventfree appliance in your home that is causing
an odor problem, it is usually the result of chemicals in the home. Many products
"offgas" chemicals such as cleaners, deodorizers, newly finished wood, new
carpet, etc.
When ventfree gaslogs
are operated for the first time they may produce an odor as the logset "cures".
This problem will disappear after 4 - 8 hours of operation. The best thing to do
is open the fireplace damper or open a window or two.
Another concern with ventfree gaslogs is moisture. A
properly operating ventfree appliance will vent only carbon dioxide and water
vapor. Carbon dioxide is the same thing humans exhale each time they breathe. The
water vapor is generally not a problem during the winter when the humidity level
is generally low to begin with. However, if you notice moisture accumulation on
the interior of walls or windows you need to ventilate the home. This may occur
in homes which are fairly airtight if the appliance is operated for an extended
period of time.
Log positioning is
another concern with ventfree gaslogs. The logs must be positioned as indicated
in the owner’s manual and this arrangement should not be altered. Most ventfree
logs have pins or groves to insure that they are installed in the proper
position. The flame should not come in contact with or touch the log. If it does
it is likely to cause sooting.
Do not
operate ventfree gas logs with the fireplace doors closed. If you do the glass
doors are likely to overheat and shatter. Also keep in mind the spark screens
installed in front of ventfree logs may become very hot while the appliance is
operating.
In summary, ventfree gas
logs are economical to operate and provide additional warmth in cool areas. They
can also provide a backup heat source in emergencies. Please carefully consider
the information we have presented here to insure a ventfree appliance is what you
want. If you have additional questions, don’t hesitate to ask.
Back to Top
Types of Gas
Gas logs may be fueled by either
natural gas or propane. Natural gas installations are preferred for several
reasons. First, natural gas is cheaper. It is also cleaner burning and considered
by many to be safer. Natural gas is lighter than air, so in the event of a gas
leak the natural gas will rise and dissipate quickly in air. Propane, on the
other hand is heavier than air and will "pool" or collect in low spots. Natural
gas is supplied by public utilities through gas mains. Propane is delivered by
private propane companies and stored at the home in tanks. Propane tanks are the
property of the propane supplier and propane companies will not fill another
company’s tank. If desired, propane installations can be set up to use 20 or 40
lb. propane cylinders which the homeowner would be responsible for filling. The
is sometimes appropriate for townhomes or condominiums where the propane company
would not be able to fill the tank.
Back to
Top
Some
common terms
BTU - British Thermal Unit, a measure of
heat equal to the energy needed to raise one pound of water one degree
Fahrenheit. Gas logs are rated by BTU input.
Therm - A measure of
heat equal to 100,000 BTU's.
Cubic
Foot - A common measure of natural gas. A cubic foot of natural gas contains
approximately 1000 BTU’s.
Pound
- A common measure of propane gas. One pound of propane contains 21591 BTU’s.
Gallon - Also a common measure for
propane. One gallon of propane contains 91690 BTU’s.
Back to Top
Other Considerations
Safety Pilots - All gas logs should be
equipped with a safety pilot control. The safety pilot maintains a pilot light
and prevents gas flow to the main burner if the pilot is not lit. We will not
install a gas log without a safety pilot. When comparing gas logs prices make
sure the quoted price includes the safety pilot control. If you are buying from a
reputable fireplace dealer this should not be a concern. However, some of the
hardware and discount stores are selling gas logs without the safety pilot. Local
inspectors will not approve the installation of a gas log unless it is equipped
with a safety pilot.
Remote
Controls - Remote Controls - Many gas appliances are available with remote
controls as an option. They usually add between $100.00 to $200.00 to the cost of
the appliance. Remote controls add a great deal of convenience to the operation
of your fireplace.
Installation
and Inspection -
Gas logs should only be installed by qualified gas
installers. Homeowners may install the gas logs if they have the appropriate
experience and tools. All gas log installations require an inspection by the city
inspector, even when the gas line is already installed into the fireplace. The
cost of the inspection runs from $30.00 to $60.00 depending on the city. Only
certified gas contractors or the homeowner may obtain a permit for the
installation. If an installer requests that you obtain the permit they are
probably not qualified to make the installation. The Magic Sweep Corporation is a
Virginia licensed Class A Mechanical and Gas Contractor and a member of the
Qualified Gas Contractor’s Association. Almost all gas log installations require
a pressure test. This test is performed after installing the gas line and before
connecting to the gas supply or logset. In other words, the gas line is run from
either the propane tank or gas meter into the fireplace. It is not connected to
the supply or the logset. The line is then capped and filled with air pressure to
test for leaks. Leaks will be indicated by a drop in pressure on the pressure
gauge. The pressure test is done at approximately 15 PSI depending on the city.
By comparison, the working pressure of an natural gas installation is 1/4 PSI and
approximately 1/2 PSI for propane. If the logset is connected to the line during
the pressure test the safety pilot will be damaged. Most gas log installations
will require three days of your time. On the first day we install the gas line
and log set and then apply air pressure to the gas line. On the second day, the
city inspector will check the overall installation and the pressure test. hen we
must come back on the third day and make the final connection to the gas supply
and show you how to operate the gas log. There are exceptions - If the gas line
has already been installed into the fireplace we simply connect the logset and
have a final inspection done. In this case the installation will only involve two
days (one for installation and one for inspection).
Maintenance
- All gas appliances should be inspected and
serviced annually and gas logs are no exception. The chimney for vented gas logs
should be inspected as well. Look for our spring mailing for special discounts on
annual service. The maintenance of ventfree gas appliances is especially
important. If the burner or orifice is fouled with dust or dirt it will cause the
burner to soot. Since the appliance is not vented to the outdoors you could end
up with a house full of soot (and possibly carbon monoxide).
Propane Tanks - For propane
installations we obtain a 100 pound tank from Bowden Gas Company and deliver it
to the jobsite. If the customer already has a propane supplier we can connect to
the existing tank. A 100 pound tank stands upright and is 48" tall and 18" in
diameter. We generally set the tank on blocks so this raises it to 54". Exception
- Putting tank on existing patio. The propane tank must be accessible for
service, either within 75 feet of the street so it may be filled with a hose or
where it can be reached with a handtruck and exchanged. In addition, the tank may
not be located where there are any openings to the home below the top of the tank
and within three feet. This includes doors, windows, and crawl space doors or
vents. In addition, the tank may not be located within 10 feet of an electrical
source, such as air conditioner, heat pump, or VEPCO meter. If the customer is
using a lot of gas the propane company will install an additional or larger tank.
Propane tanks are the property of the supplier, and propane companies will not
fill another company’s tank.
Gas
Lines - We install galvanized pipe as the fuel line. This
is cut and threaded on-site. The gas line may be run in crawl spaces, in the
attic, underground, or along the outside of the home. In the firebox, we use a
short length of copper tubing or a flexible connector from the gas line to the
logset.
CO Detectors - For safety’s
sake, we recommend a CO Detector for all homes with a gas appliance.
Woodstoves
- Gas logs are not intended for
installation in woodstoves and Magic Sweep will not do this.
When installing any gas appliance consult the manufacturers
installation instructions and local codes. The use of a qualified gas installer
is recommended for the installation of your gas hearth appliance. The Magic Sweep
Corporation is a Qualified Gas Contractor and fully licensed by the Commonwealth
of Virginia for gas installations. Give us a call and we will handle the complete
job for you. We sell gas equipment, including gaslogs and inserts, and we also
install them. We will take care of getting all required permits and even arrange
the installation of a gas line with the gas company if gas is available but not
currently connected to your home.
Back to Top
"Learn all about 
