Oil and Gas Furnaces

Gas furnaces burn fuel which can be hazardous just like any fossil fuel. Furnaces using gas or oil fuel need carbon monoxide detectors and failsafe shutoff valves to keep you safe from poisoning or fire. Modern furnaces are very well engineered and all professional HVAC technicians should install detectors as part of the heating installation.

The overall rate of failure for vents and flues is very low, but you still need to be cautious around any combustible equipment. Eventually a machine will fail, especially at the heat exchanger. Propane and natural gas are the two ways gas is used to heat your home. Some Denver heating experts prefer propane because it provides around 2.5 times as many BTUs of heating per cubic foot. Interestingly the two heating gases are delivered in different ways. Natural gas needs a pipeline to be delivered while propane is commonly bottled and trucked in. Naturally odorless and clear, they have a strong smell added to alert people of leaks.

Be careful of gas leaks as the gas will behave differently. Natural gas rises, while propane sinks and can collect on the ground. The air handler heater furnace contains a valve manifold and burners which heat up to thousands of degrees. A heat exchanger is a special device designed to withstand this heat and convert it into warm air to heat your home. The safety systems disengage the gas and keeps the fan on when the temperature has risen to a dangerous level.

Some high efficiency burners for commercial Denver HVAC have two stage furnaces which force air into the second stage like a supercharger. As the air is forced out the ventilation shaft, the fuel is burned at a very efficient rate. However two stage burners like these are only economical in large commercial applications.

Oil provides even more BTU's per volume, but as a liquid, it has a fixed volume that cannot be compressed like propane. Denver furnace repair techs like oil furnaces because they are simple and the technology has been around a while. The oil tank should be a considerable distance from the burners when doing HVAC design. The oil line and tank should be inspected for leaks, and oil furnaces need filter replacements as well. The operation of oil heaters is actually very similar to gas, except that the flue on an oil furnace needs a barometric damper to detect oil levels.

Air Handlers and Heating

Usually the air handler is the unit that provides heat, but some more advanced commercial and residential heating systems use zoning with remote heating. In this case the handler just provides air while the heaters provide zoned heat. Even inside air handlers there are multiple forms of heat energy.

You can have electric heat strips which are like super hot ribbons to heat air with. For chemical heat, gas and oil furnaces are popular with Denver furnace services companies. Some units heat a liquid which then warms the air through a heat exchanger. Hot water coil and heat pumps are examples of this type of technology. Hot water coils usually use a fossil fuel to heat the water, while geothermal heat pumps use the energy from the ground.

Electrical energy is the most common in commercial Denver HVAC applications. Electrical energy does not waste as much energy as the combustion of fossil fuels in furnaces, however electrical is still more expensive per unit of energy than any other alternative. Electrical heaters generate heat by passing high voltage electricity though a metal resistance strip. They use a lot of energy, so you need to make sure both the electrician and Denver HVAC engineer are on the same page putting in all proper wiring and and circuit protection.

All wiring needs to be well insulated for this type of high energy electric work. You need circuit protection and fail safe breakers that will shut off in the event of a short or overheat.

Remote heating in air handlers use a switch to energize the heater when air flow is detected. This is important to have air flow to keep from wasting energy and reduce the chance of fire. This is an added risk with heaters all over the house. On the other hand, for buildings that will only need heating in certain locations, zone controls can result in significant savings. Remote heaters can even be gas duct furnaces. Zoning can be installed by a Denver furnace repair company, and they not only save money but also result in more even heating. They provide heat by burning gas in the ducts, but they also need air flow when operating.

Air Handler Fan and Heat Relays

The relay between the air handler control unit and the blower motor is called a fan or heat relay. If the thermostat fan setting is "on" then the relays do nothing but keep the fan running. Otherwise, when the air handler controller asks for heating or cooling the relay switches the fan on.

The relay allows the fan a short delay to spool up before it starts heating or cooling. This increases efficiency by allowing th blower to push already conditioned air in the ducts through before additional heating or cooling takes place. Instead of that air being wasted in the handler it is used for cooling your house.

Cool evaporator coils work best, so when the cooling cycle starts you will be operating at maximum efficiency. The cool coils can absorb more heat, according to Denver air conditioning services. Some controls use a fan limit switch to set when the unit turns on or off. The fan limit switch is used on furnaces where the fan control circuit is mounted on the heat exchanger.

The fan limit switch on these gas and oil furnaces energizes the fan when the heat exchanger reaches a certain temperature. For most thermostats, the white wire runs to the fan limit switch. It acts as a safety device, because if the burner gets too hot, the white wire will shut it off and keep the fan running to dissipate heat.

The heating relay is separate from the fan relay. The control board has several safety switches before it goes to the furnace to keep it from overheating. Electrical heaters should have a thermal safety fuse installed by a Denver furnace repair company that will physically melt and break the electrical connection if the furnace gets too hot.

Because furnaces are so dangerous, they have numerous fail safe controls, some of which may be manual reset. This means it will stop your house from burning down, but you may have to call a Denver HVAC technician to come reset the fuses. If the switch was tripped for no apparent reason, ask the technician which switch was tripped so that you will know where the problem is if it happens again. Most fuse and breaker switches can be replaced at a minimum cost.