Common Gas Furnace Parts and Problems

Old gas furnaces were pretty simple; just a burner and a fan to circulate air. Every furnace must have a few components to work properly. The first component between the gas intake and the furnace is the gas valve. Propane and natural gas valves are different because the gases have different densities. However many gas valves can be converted between the types without having to order a whole new part. Call your Denver heating company to see if this is possible. In some jurisdictions, switching or installing new components requires inspection for following the fuel-gas code. Before performing any work on a gas valve, make sure you turn off the gas lines going in and out.

The gas manifold maintains proper pressure for the burner. It is on the gas line between the gas valve and the burner. The pressure is sensitive to the type of gas and the specific furnace, so make sure you get a qualified Denver furnace repair man to set the pressure. Manifolds usually do not require much maintenance unless insects or other foreign material gets inside the gas panel.

For everyone other than HVAC specialists, the burner is the exciting part of the furnace. All burners shoot a flame into a combustion chamber that has a draft sucking air in. At high altitudes like in Denver, the size of the burner hole needs to be smaller because there is less oxygen in the fuel-air mixture at lower atmospheric pressure. If you bought your furnace somewhere else and moved to high altitude, you may have to call a Denver furnace service company to modify the burner outlets.

To keep the burners fed with air, you need some sort of ventilation system. HVAC includes not only the ducts that bring treated air around your home, but a ventilation system for the burner. The furnace needs a way to bring in oxygenated air and safely vent the burnt exhaust.

The combustion chamber is not directly connected to your heating ducts to keep you safe from dangerous exhaust. The heat from the furnace is passed onto the air through a heat exchanger. These heat exchangers are made from thick metal that can withstand the constant high heat from the burner. Heat exchangers should be regularly checked because any crack in the material can release exhaust directly into your house.

Furnace Flame Efficiency

Modern furnaces are a lot more complicated than just burning gas and air. To work properly, your furnace regulates the air-fuel mixture. Natural gas and propane used to be cheap forms of heating, but as they become more popular those days are ending. As the prices for fuel increases, the efficiency of the burn becomes more important. Natural gas is a light fuel that should burn blue. A yellow flame in a natural gas furnace probably means that it is not getting enough air. A Denver furnace repairman should be able to adjust the airflow to fix a yellow flame rather easily.

Other common problems with furnace flames are flames that flicker or roll out. An adjustment to your furnace will be necessary in most cases. The HVAC tech may have to test the actual composition of the flame with an expensive instrument called a a combustion analyzer. The analysis tells your Denver HVAC technician the temperature as well as the levels of carbon dioxide, monoxide, and oxygen given off by the flame.

Having the furnace fumes completely exhausted outside the home is very important. Carbon monoxide can lead to headaches, nausea and even death. A dirty burning furnace can have other toxic byproducts as well. Your Denver furnace repair company should do a furnace draft test to make sure your furnace is not leaking exhaust into your home.

I recommend all homes have a carbon monoxide detector installed to protect the occupants from this invisible, smell-less gas. Carbon monoxide poisoning is no joke and long term exposure can cause brain damage. Carbon monoxide basically replaces oxygen in your blood and starves your brain of oxygen. During my work in my Denver HVAC company, we usually find 4-5 homes a year that have a carbon monoxide leak, so there must be many more that are completely unaware.

If the problem with your furnace flame is the gas level and not the air mixture, your HVAC guy should do a gas pressure test. Depending on the type of fuel (natural gas, propane, or heating oil) the required pressures are different. The optimal level will lead to complete combustion of the fuel.

How to light a pilot

In my business, the pilot light is the thing that has the biggest earnings/cost ratio. Poor consumers often pay over $100 for a HVAC technician to come light their pilot. The actual time of work is usually less than one minute. Lighting a pilot light does have a small degree of risk, but the average consumer needs to know how to do it themselves so they do not have to call their Denver heating company every time the light blows out.

The pilot is a very simple device that keeps a small flame for igniting your gas furnace blowers. Sometimes the hardest part of lighting a pilot is finding it. Many people know where their thermostat is and that is the extent of their HVAC knowledge. Sometimes the pilot is deep inside of the furnace unit and you will need a long match or BBQ lighter to get the flame close enough. If the pilot does not light, then you will need to call your Denver furnace repair services company because the problem may be much larger than you expected.

If your furnace is not heating, first check where you always would: check that the thermostat is on. Then check the filter, because a clogged or nonexistent filter will damage your HVAC equipment quickly. The power to your furnace or thermostat may also be off at the circuit breaker. Then check that you have gas flowing. If you have natural gas, check the meter to make sure your gas is turned on. For propane heating, obviously check the tank pressure and valves to see if they are open. The valve at the furnace is called a gas-cock and should be parallel to the inlet or turned to "pilot" or "on" for it to work. These simple checks are the most common reason for failed furnaces, and will save you money calling the Denver HVAC company to your house to flip a switch.

Some furnaces have an intermittent pilot that works with electronic ignition. The pilot is only lit when the HVAC system needs it, and it is lit with an electronic spark. This means the pilot does not need to be lit all the time. If it does not ignite automatically, call a Denver furnace repair company and do not attempt to light it yourself.

If the pilot is manual an unlit, first turn the knob to pilot before lighting. The flow of gas for the pilot should be so low that you will not smell any gas. Natural gas rises, while propane sinks and collects along the ground. If the pilot goes out, the valve that supplies it gas will automatically close and your furnace will not work. You will need to turn or hold the knob in the pilot position to get the gas flowing again.