Knowing Which Gas Appliance Sits in Your Genola Hearth

Three types, and why the difference matters

A vented gas log set sits in a real wood-burning fireplace and burns with the damper open. All its exhaust goes up the chimney, along with a great deal of room air, so it is decorative rather than efficient. It is also the type most often found in older houses here, dropped into an existing masonry firebox at some point in the past.

A direct-vent appliance is a sealed unit behind fixed glass, taking combustion air from outside and sending exhaust outside through a coaxial pipe. It never uses room air and never puts combustion products into the room, provided the glass gasket and the vent joints are intact. This is what is in most newer construction and it is the type we would recommend to anyone.

A vent-free appliance burns gas in the room and exhausts into the room. Manufacturers design them to burn very cleanly and they include an oxygen depletion sensor. We will still tell you our honest view: we are not enthusiasts. Every cubic foot of gas burned indoors releases water vapor into the house along with the combustion products, and the margin for error when the burner is dirty is much smaller than on a sealed unit. If you have one, keep it scrupulously clean, do not run it for long unattended periods, and have working carbon monoxide alarms.

Fuel matters as much as type out here. A good many properties around Genola sit off the natural gas main and run on a propane tank, and the same appliance on propane needs different burner orifices and a different regulator setting than it does on natural gas. We confirm what is in the tank and what the unit was actually set up for before we touch the burner, because an appliance running on the wrong orifice sizing will soot itself up long before anyone thinks to call.

Dust and field air

This is farm country. Ground gets worked, fields get cut, and there is pollen and fine dust in the air through a good part of the year. A gas burner mixes air and fuel through small openings, and a partly obstructed air path gives you a rich mixture, lazy yellow flames and soot. Cleaning the burner, the venturi and the pilot assembly is the core of an annual service and it is not a formality on a house surrounded by open ground.

What we check, and what we will tell you

Glass out, gasket inspected, burner and pilot cleaned, logs cleaned and reset to the manufacturer's own diagram because a log moved into the flame path is the commonest cause of sooting, thermocouple or thermopile output measured rather than judged, safety shutoff actually tested, gas pressure checked at the appliance, blower cleaned, vent run and termination inspected, then a full test burn watched from cold.

If your unit is an old vented log set in a masonry fireplace and you want warmth rather than a flame effect, we will tell you a sealed insert is the better use of your money, and we will tell you if the fireplace can take one. If it is a sealed appliance in good order, we will say so and leave it alone. Licensed and insured.