If your gas furnace is making clicking noises, you should call in a professional furnace repair service as soon as possible to find and repair the source of the noise. Here are three common problems that cause gas furnaces to click, along with ways these problems can be rectified.

Ignition Failure

If your gas furnace is not creating any heat but creates a clicking noise when you try to activate it, the furnace's ignition system may be the source of the irritating noise. All gas furnaces rely on ignition systems, which ignite the gas that enters their combustion chambers. Older furnaces may rely on a standing pilot light, a small flame that burns continuously. Newer models are more likely to be fitted with electronic ignition systems, which ignite the furnace's gas supply by creating electrical sparks inside the combustion chamber.

Both types of ignition system can create clicking noises when they activate, but if they are malfunctioning, they may click continuously as the system repeatedly tries and fails to ignite the furnace's gas supply. This may be caused by the pilot light or electronic igniter itself. In other cases, the igniter may be functioning properly but fails to ignite because insufficient gas is reaching the combustion chamber.

If your non-functioning furnace is clicking continuously, deactivate the system, and call in a professional furnace repair service as soon as possible. If your furnace's ignition system is faulty, repairing or replacing the system will usually fix the problem. If gas supply problems are the cause, the valves and pipes that funnel gas into the combustion chamber may need to be replaced.

Heat Exchanger Damage

The heat exchanger is one of the most important parts of any gas furnace, but years of continuous use can take their toll on these vital components. If your gas furnace appears to be functioning normally but you hear an intermittent clicking noise while it heats up, this may signify cracks in the heat exchanger. The clicking noises are caused by the cracks themselves, which expand as the heat exchanger heats up.

Damaged heat exchangers are a leading cause of dangerous carbon monoxide leaks. If you notice your gas furnace is making periodic clicking noises after activation, shut the system down immediately, and call for an emergency repair service. Once a heat exchanger starts to crack, it must be replaced before the gas furnace can be used safely.

Blower Fan Bearings

If your furnace is providing adequate heat but is making rapid clicking noises while it functions, one or more of the furnace's blower fans may have worn or faulty bearings. These bearings allow the blower fans to rotate smoothly. If they become worn or damaged, the fan(s) may make loud clicking noises as they rotate.

Fortunately, this problem can be rectified by a furnace repair service. Once your chosen service has replaced any worn or damaged bearings, the clicking noises should cease.