How To Clean A Furnace Ignition Sensor

A muddy flame sensor is 1 of the virtually mutual issues that homeowners encounter with their furnace systems.

If you lot notice that your furnace fires up, just shuts down before long after, the chances are you've got a dirty sensor, too.

Fortunately, it's a super simple fix, and one that nigh people, even those without mechanical inclination, tin can tackle themselves, without the demand for a costly HVAC repair service.

In this proHVACinfo guide, we'll be learning about:

What Y'all Demand To Know About Furnace Flame Sensors (why they are causing problems)
Tools And Supplies You'll Need For Cleaning A Furnace Flame Sensor (don't go started without these 3 things!)
How To Clean A Furnace Flame Sensor (five footstep guide)

And much more!

What You Need To Know About Furnace Flame Sensors

Gas powered furnaces are extremely rubber and efficient heating systems, only absent safety features like flame detectors, they can get ticking time bombs, literally.

The flame sensor is a slim metal rod mounted in porcelain , placed in front of the flame jet inside the organisation.

They conduct electric current, which detects the presence of a flame due to an increment in temperature.

The flame sensor's job is to detect the presence of a flame in the furnace if the gas valve is in the open position and the gas is flowing.

If the flame has been somehow extinguished, and there is no automation telling the gas valve to close, this can cause an extremely unsafe explosion take a chance.

To prevent an accumulation of gas in the organisation, or worse, from leaking out into your dwelling house, the flame sensor has to human activity most immediately upon ignition of the burners.

Every bit a safe measure, if no flame is detected, the organisation will automatically close off the gas flow.

Nigh residential systems have a lockout period if multiple attempts are made to first the furnace with a faulty flame sensor.

This safety automation volition end the system from operating birthday for a predetermined period if the maximum number of starting attempts are exceeded in a certain window. The number of attempts and period of the lockout window vary between systems and manufacturers.

This is why a faulty flame sensor can cause your furnace to start upward and shut down shortly thereafter.

Because furnace flame sensors are such simple parts, all out component failure is pretty rare. In virtually cases, exposure to open flames leads to a buildup of carbon on the sensor itself.

As the sensor works past indicating a change in temperature, even a microscopic buildup of carbon can alter the temperature at which the sensor detects a ascent in heat.

The greater the carbon buildup, the more dramatic this will exist, and in plough, the longer it will take to acknowledge the presence of a flame.

If the period of time the sensor takes to detect the estrus increment exceeds the born tolerances, the system will shut down considering it believes that no flame is present.

In addition to carbon build-up, flame sensors can also collect dirt and grit quite hands. Most people tend to go on their furnaces in their basements, which are typically a fiddling more damp than the rest of their homes which will cause clay and debris to stick to, and build upwards on components similar your flame sensor.

Supplies You'll Need For Cleaning A Furnace Flame Sensor

Considering this is a task almost all homeowners will be able to achieve on their own, the tools required are quite limited. To admission, remove, and reinstall a furnace flame sensor in near residential systems, you will need:

A hex driver or socket prepare – The bulk of furnace systems will only demand a ¼ inch hex commuter or socket, but equally this varies betwixt manufacturers, having an array is helpful. Nosotros always find it useful to accept a ratchet set, as it speeds up the console removal and reinstallation.

Wire wool and low-cal grit sandpaper – Wire wool and light dust sandpaper are both essential abrasives for getting the carbon build-upward off the sensor.

Microfiber rags – Microfiber rags are a better choice than paper towel or non-microfiber rags because they don't get out strands or fibers behind when you're cleaning. If you wipe downwards the sensor with paper towel, and you get out paper fibers backside, they volition burn down off when the sensor goes back in the system, which will get the rebuild of carbon off to a caput beginning – non something you want!

How To Make clean A Furnace Flame Sensor (v Steps)

Step 1: Shut Downwards the Power

Whenever you dismantle a organization like a furnace, there is a chance of electric shock, and not only that, if the furnace is not shut downward, and it starts by a thermostat or timer while you're working, you could go seriously burned.

Out of an abundance of caution, yous should always remove the power supply to the unit.

Remember, simply stopping the automatic temperature control at the thermostat does not count as shutting off the organisation! Y'all need to physically close off the power.

Most systems take a difficult on/off switch somewhere on the unit. If y'all can't find one, identify the right circuit at your breaker box and switch it off. We like to suggest using the on/off switch and the circuit breaker if possible.

The method of operation for every manufacturer and system model is unlike. For that reason, the instructions here are only a crude guide to the overall process. Always read your manual, and if you lot're not confident that you can take on this task safely, stop and call a professional.

Step 2: Remove The Flame Sensor

Using your hex commuter or socket gear up, open the outer panel and store the screws somewhere safely nearby.

Your flame sensor should exist like shooting fish in a barrel to access, and is likely somewhere well-nigh the opening of the console.

It should be mounted with the same hex screws as the outer panel screws, so you lot shouldn't even need to change tools.

Fifty-fifty when unmounted, the flame sensor should still be attached by an electrical wire. If it'southward attached by a quick connectedness, it'southward probably worth removing it birthday in society to get the best admission to all areas of the sensor. If not, y'all should probably take enough slack in the wire in gild to clean the exposed metallic part of the sensor.

Step 3: Start Cleaning The Sensor

Remember, the base of operations is well-nigh probable made of porcelain, and is therefore quite delicate, then be conscious of this when treatment your flame sensor.

It's at present fourth dimension to outset scrubbing! Information technology'southward but necessary to clean the metallic rod, so avoid contacting the porcelain or other components with your cleaning tools.

Start gently rubbing the rod with the sandpaper in club to remove the bulk of the buildup. Once you lot see bare metal again, it's time to wearisome down.

Y'all don't want to remove any material other than carbon buildup. Once the bulk of the carbon and other dirt is off, become in with the wire wool, especially around whatever curves on the rod.

When yous're happy with the state of the sensor, take your microfiber rag and wipe off whatsoever carbon grit left on the sensor and the sensor mount.

Step 4: Reassemble

Now that your flame sensor is as proficient as new, it'south time to put information technology all back together again. The process for reassembly is the exact reverse of the disassembly.

If you physically disconnected the sensor, now is the time to reattach before setting information technology back in its mountain and screwing it tight.

Put the comprehend panel dorsum in identify and tighten the securing screws support.

Don't over tighten these, they should be a little squeeze past finger tight but not much more, or you take a chance stripping them.

Turn on the gas and power supplies, and you're ready for the next footstep.

Stride five: Exam The System

Modern furnaces are fabricated with a number of built in safety controls, some of which may kick in automatically subsequently the arrangement has detected a restart after a menstruation of no power.

These are normal, so don't worry if your furnace doesn't roar into life the second you turn it back on. Subsequently the system cycles through its checks, information technology should either be in standby, or start running, depending on the thermostat settings.

If information technology'southward in standby, go to your thermostat and suit the temperature then that the furnace should turn on 1 degree before the ambience temperature. This will check that the thermostat link is still working after your reassembly, and it should also exam the flame sensor, too.