A client in Pasadena, CA, called us for furnace repair. Even though they set the thermostat to heat and the temperature high enough, their furnace was still not blowing hot air. When we looked at the air handler, we found a damaged part that caused the igniter to fail. The hot surface igniter at the back of the combustion chamber had cracked, most likely due to overheating. The electrical resistance test proved the igniter’s silicon carbide had gone bad. That caused the current to flow outside the ignition coil, rendering the system inoperable. We replaced it with this silicon nitride hot surface igniter, which lasts longer than its silicone carbide counterpart. With this easy fix and the extra cleaning service, we restored the furnace to its best running condition. Now, the client can heat their home and stay warm all day! And lastly, they could get their daily activities back on track without being cold or uncomfortable.
As the cold weather comes, replacing any components in your heating system over a year old is essential. Many furnaces will not light up when they are first turned on this winter — even though it may have worked fine for all of last season. One of a furnace’s most often replaced components is the hot surface igniter. These generally do not last more than a couple of years before they need to be replaced — and some can falter as early as six months. Stay with us as Pioneers Heating and Air discuss this integral sequence component to bring heat into your home.
A hot surface igniter (HSI) ignites the gas inside appliances such as stoves, water heaters, furnaces, and boilers. HSI systems are commonly used in appliances that burn natural gas or liquid propane but can also be found on propane vaporizers, wood stoves, and oil burners. These “glowing” devices are often made from ceramic materials and release infrared energy that ignites when close to a pilot flame.
Igniters are typically made from silicon nitride or silicon carbide. Most nitride igniters are long cylinders or flat sticks. The igniter is typically mounted on top of a gas valve. It passes through each section as the flame from the burner moves up the burner tube. That prevents black-lighting when directly lighting the burner without a pilot, which could lead to an explosion or fire. When the valve opens, the flame “ignites” and begins heating your home.
Hot surface igniters are designed to last for several years with normal use. However, they may be used much more frequently during the heating season and may not last as long. Different types of hot surface igniters have different lifespans. In recent years, igniters made from durable materials like silicon nitride have become more popular because they are less likely to break down over time.
HSIs are made of very brittle materials that will readily break. In fact, if you bring your index finger and thumb together quickly enough, the force would be enough to shatter the carbide tip of a hot surface igniter. And if the ignitor stays on for an extended period, this will make the ignitor more brittle.
It is important to have an HSI that is the right size for your home. We often say that an improperly sized unit will cause all sorts of problems, such as cycling on and off excessively. In addition, overworked HSIs will break down faster and cost you more money in the long run.
HSIs are designed to operate within a specific voltage range, and exposure to voltages outside of this range can cause damage or early failure. For example, an HSI rated for 80 volts should not be exposed to 120 volts, as this will likely cause the HSI to break.
Is your furnace not blowing hot air? Pioneers Heating and Air is your local HVAC contractor serving the Altadena and Pasadena, CA, area. We are your one-stop shop for all your heating and air needs. Our services include furnace repair, hot surface igniter replacement, and seasonal maintenance. We have expert technicians who are committed to providing the best possible customer experience and are ready to solve your heating or cooling problem. Contact us today to schedule a consultation!