What’s a Furnace Capacitor and Why Do They Fail?

Furnace capacitors are small elements that not often come up except there’s a difficulty.

If you happen to’re trying to find info on a furnace capacitor, it’s seemingly your HVAC service associate just lately identified your furnace with a nasty or defective capacitor. 

Like different industries, HVAC comes with its personal jargon. If you happen to’re not conversant in the technical phrases, it may be difficult to grasp your service technician’s skilled prognosis.

At Hearth & Ice, we now have virtually twenty years of expertise with HVAC. Over these a long time, we’ve acknowledged that offering high-quality HVAC service and restore goes past even the technical expertise of our technicians. 

Throughout service calls, we take the time to assist our clients perceive any points with their HVAC system. We’ve created this text to reply questions on furnace capacitors. 

On this article, we’ll cowl what a furnace capacitor is and the way it works, indicators and explanation why furnace capacitors fail, and the best way to get probably the most out of your furnace capacitor. We’ll additionally weigh DIY {and professional} capacitor alternative.

What Is a Furnace Capacitor?

A furnace capacitor helps regulate energy enter to the motors positioned in your furnace. These motors can embrace blower motors and, in some circumstances, inducer motors.

Visually, a furnace capacitor is a small element that you could be see mounted on the blower fan compartment in some furnaces.

A furnace usually has a number of capacitors that regulate energy for various elements. We will break capacitors down into two sorts: begin capacitors and run capacitors. 

Since your HVAC service technician might also talk about capacitors when it comes to “begin” and “run,” let’s take a second to interrupt these down as effectively.

Furnace capacitors fall into the class of run capacitors. Run capacitors handle energy to a element whereas it’s actively working.

Begin capacitors are answerable for regulating energy to a element that requires substantial electrical energy to activate. Begin capacitors are mostly present in air conditioners or warmth pumps. In furnaces, run capacitors additionally double as begin capacitors.

The quantity and kind of capacitors in a furnace can fluctuate relying on the producer and mannequin.

What Does a Furnace Capacitor Do?

We’ve already mentioned a furnace capacitor’s primary operate: to manage the circulate of electrical energy to elements just like the blower and inducer motors. However why is regulating energy enter mandatory?

Your furnace homes your system’s blower motor, which powers the fan that helps transfer conditioned air all through your own home year-round. Each time your system heats or cools your own home, your furnace’s blower motor kicks on.

You could even select to run the fan even when your HVAC system isn’t actively heating or cooling your own home. This might help enhance circulation and air high quality.

No matter its gas supply, HVAC tools requires high-voltage electrical energy to warmth or cool your own home. This electrical energy powers elements like your blower motor.

Furnace capacitors regulate energy to your blower motor throughout startup and because it continues to run.

And not using a capacitor, energy enter can fluctuate. With a capacitor, the enter is regular. This helps keep constant efficiency and helps maintain the motor from straining itself. 

2 Frequent Indicators a Furnace Capacitor Isn’t Functioning Correctly

On the subject of furnace capacitors, you might not at all times discover that there’s a difficulty immediately. 

A furnace capacitor itself usually doesn’t present indicators of failure. As an alternative, you might discover a number of oblique indicators {that a} capacitor isn’t functioning correctly.

Two of the commonest indicators that your furnace capacitor isn’t functioning correctly or has failed:

• Your blower motor is noisier than normal – If the blower motor is noisier than normal when the fan kicks on, the capacitor could possibly be weakening. The commonest noise is a whirring or buzzing noise that sounds just like the fan is ramping up.

• Your blower motor that doesn’t activate in any respect – If you happen to discover that your fan isn’t working in any respect, this could be a signal of a nasty capacitor.

These indicators are commonest in permanent-split capacitor blower motors, a kind of blower motor that was phased out throughout the trade in 2019. 

Nonetheless, in case your system has a variable-speed blower motor, the probabilities of it failing are comparatively low.

Why Do Furnace Capacitors Fail?

A furnace capacitor usually solely fails for a number of causes:

1. The capacitor reaches the tip of its lifespan

2. The blower motor is below pressure

As with every mechanical element, furnace capacitors have a mean lifespan. Capacitors usually final 10-15 years. In some circumstances, a capacitor simply reaches the tip of its lifespan.

However typically, the capacitor is only a symptom of a much bigger problem. For instance, in case your blower motor is below pressure, it’ll make the capacitor work tougher as effectively. 

So what occurs when a furnace capacitor fails? In lots of circumstances, you may get your furnace again up and working by simply changing the capacitor. Different instances, you might want to interchange your blower motor to deal with bigger points together with your system.

Your HVAC service technician ought to conduct a full inspection of your furnace. It will assist decide whether or not the difficulty goes past the capacitor.

Can You DIY Furnace Capacitor Alternative?

The quick reply: For security causes, we might by no means suggest {that a} home-owner change any capacitor themselves.

As we’ve mentioned, capacitors regulate high-voltage electrical energy. Working with high-voltage elements with out the correct expertise or instruments can have painful and even deadly penalties.

DIY furnace capacitor alternative additionally dangers damaging your furnace if the capacitor is put in incorrectly. In some circumstances, DIY work can void your furnace’s guarantee, which implies that you’d be caught with any restore or alternative prices if one thing goes flawed.

Though there are numerous on-line guides on DIY repairs for furnace capacitors, we extremely suggest leaving this to an HVAC skilled.

Skilled Furnace Capacitor Alternative

Your HVAC service technician ought to be capable of change the defective furnace capacitor shortly and safely. 

As soon as the brand new capacitor is put in, your technician ought to verify that the capacitor is functioning appropriately. This entails taking a studying and observing the blower motor because it begins up and runs.

Blower motor and fan alternative might be extra expensive and labor-intensive. Though it’s not at all times potential, stopping pressure on the blower motor might help keep away from a few of these prices. 

Your service technician ought to take the time to stroll you thru your choices. Whatever the scenario, your technician ought to by no means stress you.

How you can Preserve a Furnace Capacitor

The easiest way to maintain your furnace capacitor and, by extension, blower motor working correctly is to often keep your furnace. 

Common upkeep helps maintain your furnace on the high of its sport. And your HVAC service supplier might help observe any modifications in your furnace’s efficiency over time.

We usually suggest two tune-ups every year to your HVAC system: one to your furnace and one to your air conditioner or warmth pump.

Throughout a furnace tune-up, your service technician ought to verify the situation of your blower motor. This additionally consists of taking a studying of the furnace capacitor.

Nonetheless, a significant a part of capacitor and blower motor upkeep is often altering your furnace’s filter. 

As we talked about, blower motors assist flow into conditioned air all through your own home. However because the filter collects mud and particles, the blower motor has to work tougher to flow into the air. 

Soiled filters can have an effect on your consolation and your pockets. Lack of airflow brought on by soiled filters additionally means your whole HVAC system has to work tougher to warmth or cool your own home. And the tougher your system works, the extra you’ll seemingly spend on vitality prices.

Your filter’s producer ought to present extra info on how regularly to alter your filter. However in some circumstances, you might want to alter your filter extra typically.

For extra info, try our article on how, when and why to alter your furnace filter.

Get the Most Out of Your Furnace

A furnace capacitor could also be one small a part of your furnace. However in relation to machines, even small elements can have an effect on the broader system’s efficiency.

It’s essential to take the time to grasp how elements affect your system’s efficiency—and also you’re doing simply that! As you proceed to keep up your HVAC system, it’s essential to have an HVAC associate you’ll be able to belief.

At Hearth & Ice, we consider in serving to our clients study extra about their HVAC system. As a result of once you perceive your system, you acquire higher management over your personal consolation.

If you happen to stay within the larger Columbus, Ohio, space, we’d love to assist keep your furnace! Use the zip code lookup under to verify should you’re in our service space.