What Is a Silicon Carbide Igniter?

Silicon carbide igniters are hot surface ignition methods used to light gas furnaces and other equipment. They provide an alternative to spark ignition which may interfere with radio/TV reception as well as interfere with arc flash circuit interrupters.

Silicon nitride (SN) igniters provide an easy upgrade from old style SC igniters, far exceeding them in quality and durability.

Long Lifespan

Silicon carbide igniters are highly durable and long-term heating components designed to withstand high temperatures and sudden fluctuations. Their design also makes them an excellent choice for gas furnaces and other gas appliances, due to their superior thermal conductivity and resilience to mechanical stress; additionally, these igniters resist oxidation and corrosion, providing reliable service in demanding applications.

Hot Surface Ignitors (HSI) function similar to light bulbs; each time your thermostat calls for heat, an electric charge is sent to an HSI that heats it until it turns red-hot – thus lighting your furnace’s burners. However, due to constant cycling between red-hot and cool states of an HSI over time it can begin to wear down over time; depending on conditions in your home an HSI should last between three and five years before replacement becomes necessary.

HSIs are subjected to environmental contaminants like sheetrock dust, condensation, dirt and fiberglass which may accelerate their breakdown more than expected. Furthermore, any oil from your hands touching it could further shorten its lifespan than would occur naturally without human interference.

While earlier HSIs were constructed using silicon carbide, newer models feature silicon nitride (SiNi) igniters to offer increased strength and resilience against wear and tear. SiNi can withstand greater amounts of use.

This newer technology enables for more effective ignition of gas furnaces, thus decreasing energy waste and improving efficiency. Furthermore, this reduces carbon dioxide emissions from burning fossil fuels as well as air pollutants such as particulate matter. Furthermore, as its silicon nitride igniter does not require continuous flame, making it safer and more eco-friendly than traditional pilot lights.

The Supco IG402K silicon carbide igniter is designed for use with all kinds of heating systems, from furnaces and boilers to rooftop unit heaters, water heaters and swimming pool heaters. This kit comes complete with mounting hardware and instructions (where applicable) for easy installation; additionally it’s compatible with many OEM manufacturers so it can replace original HSIs easily in your system.

Low Maintenance

Silicon carbide igniters require far less maintenance than traditional pilot lights, especially in terms of their heating up speed and energy use. Since they use electricity to spark fuel burning furnaces and reach ignition temperatures within seconds – meaning less energy usage and thus increased efficiency and reduced costs associated with energy consumption.

Silicon carbide is resistant to corrosion, meaning that regular cleaning isn’t required for it. Field experts do advise ensuring the ignitor remains clear of contaminants such as oil from hands. Furthermore, direct handling will damage its tip over time from exposure to contaminants.

To perform a maintenance check on an ignitor, begin by identifying and removing any screws or clips securing it to its base. Next, carefully disconnect electrical wires from the ignitor while taking note of their connection points so they can be reconnected correctly later. Check insulating sleeving surrounding wires for signs of chafing, burned portions or cuts; pull on igniter to see if it has become loose from its ceramic holder.

If there are signs of trouble with your ignitor, a hot surface ignitor upgrade kit from manufacturers like White Rodgers or Supco can help replace it with an updated silicon carbide one.

These kits are designed to ensure optimal performance of your furnace system. The ignitor will have optimal velocity, which promotes efficient combustion and minimizes fuel waste, as well as being safer than constant flame pilots because its continuous burn requires less energy consumption, which reduces gas leakage risk. Plus, using less energy helps improve overall heating system efficiency while saving on energy bills! This investment in your comfort will bring years of enjoyment.


Silicon carbide igniters, also referred to as glow plugs or glow sticks, use electricity to produce heat that then ignites combustion of gas within furnace burners. This form of heating system offers more consistent, safer and cost-efficient natural gas home heating compared with traditional pilot lights.

Original igniters used by most furnace manufacturers were composed of gray and sparkly material similar to what’s used to make artificial whetstones for sharpening knives, and mounted onto nonconductive ceramic bases. While functional, their lifespan was short and brittle; often cracking or breaking after being dropped or exposed to grease and dirt. They were the leading cause of no heat calls.

These issues were overcome through the creation of modern silicon nitride ignitors which are more resistant to heat while withstanding abrasion, vibration, expansion, and other stresses found within a furnace environment. They are rated to last much longer than their older silicon carbide counterparts and can be operated using both AC and DC current between 24V and 120V voltage levels.

Although these igniters are less costly to produce than their predecessors, their installation process is more complicated. HVAC construction technicians are still getting used to the different sizes and positions of these new ignitors; any misinstallation could lead to misfires or delayed ignitions.

Robertshaw 41-402 Carbide Series Hot Surface Ignitors feature recrystallized silicon carbide bases that combine physical and thermal strength, stability, and flexibility with lead wires crafted of 18 gauge copper coated with high temperature fiberglass coating for protection and conductivity. They can reach ignition temperatures within 17 seconds when used as replacement or upgrades on rooftop heaters, water heaters or unit heaters and also come complete with protective sleeves to ensure safe handling and secure fit; all Robertshaw igniters come backed by their 1-year warranty from Robertshaw!

Energy Efficiency

Silicon carbide igniters can be utilized in multiple heating systems. Renowned for their durability and resilience, silicon carbide igniters make an excellent choice for gas furnaces as well as other appliances. In addition to being cost-effective with minimal maintenance needs and wide temperature and environmental conditions tolerance. Their use makes for a fantastic alternative to more fragile traditional pilot lights which are susceptible to being easily damaged from dirt accumulation.

The igniter contains an internal combustion chamber that can be adjusted to accommodate different fuels, providing improved energy efficiency and combustion performance resulting in lower emissions. Furthermore, its insulating properties protect it against corrosion and extend its lifespan.

Igniters can be combined with sensors to monitor and control heating systems. Sensors provide real-time information and notify technicians immediately if issues arise, ensuring optimal system performance. They may also help optimize ignition processes reducing fuel consumption while improving combustion.

Silicon carbide (SiC) is an adaptable material used in many different fields from abrasives to refractories. SiC’s versatility has found many uses from gas heating equipment due to its superior thermal conductivity and corrosion and oxidation resistance, as well as being an excellent electrical insulator – saving energy when sparking.

To assess the differences in performance between CSI and RMPI, several experiments were performed in the component combustion chamber of a high-altitude environment simulation testing system. As a result, these experiments revealed that RMPI has higher discharge cycle energy than CSI, as well as 26% greater electric power conversion efficiency.

Discharge energy of a spark depends on its duration and voltage intensity; the longer its duration is, the greater its discharge energy will be. Furthermore, more c-shaped electrodes with larger spacing between them result in larger discharge channels while in contrast, CSI has smaller electrode gaps and shorter channel lengths.

Hot surface igniters currently used in gas heating equipment have been around for many decades. Constructed of silicon carbide or silicon nitride with ceramic bases to encase their wires, when powered with 240V electricity they create an ignition surface capable of lighting biomass fuels more effectively than previous methods and are therefore much more energy-efficient than prior technologies in most furnaces. Furthermore, this type of igniter is easily compatible with most brands as well.

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