Furnace repairs are common this time of year. One of the most common problems is a bad igniter.
There are several types of igniters:
- Hot Surface Igniters
- Direct Spark Igniters
- Standing Pilot Igniters
Hot Surface Igniters:
In this video we replace a hot surface igniter. The old igniter had a carbon build-up and was no longer getting hot enough to light the gas during the brief interval the gas valve opened and the system checked for a flame. Since the hot surface igniter is made out of silicon material, it is very fragile and can break very easily. Uneven heating from the carbon build-up can also break the igniter. Once damaged or with too much carbon buildup, the igniter no longer ignites the gas prior to the unit checking for a flame and then shutting the gas valve off after detecting that there is no flame.
Direct Spark Igniters:
Typical repairs for direct spark igniters are carbon buildup on the igniter rods or a damaged transformer on the circuit board. These igniters generate 10,000V at the circuit board and then spark agross the rods to create the ignition source for the gas. If the rods are rusted or covered in carbon buildup, then the spark has a hard time jumping the gap. Also the circuit boards have a transformer needed to create the 10,000 volts and sometimes those transformers go bad and the circuit board must be replaced.
Standing Pilot Igniters:
Standing pilot igniters have a different set of typical problems. Here sometimes the pilot is blown out. Other times the thermocouple goes bad and no longer sends the signal to the gas valve. If the thermocouple is bad, it typically just needs replacing.
