Gas Heat ESCO Practice Exam

A furnace with a hot surface igniter will not light. Before changing the igniter the technician should:

1. check for gas leaks.

2. check thermostat settings.

3. check voltage to igniter

4. clean the burner assembly.

The correct answer is: check voltage to igniter

In the context of troubleshooting a furnace equipped with a hot surface igniter, checking the voltage to the igniter is a critical step before proceeding to replace it. The hot surface igniter relies on electrical current to heat up and ignite the gas in the combustion chamber. If there is insufficient voltage or no voltage reaching the igniter, it will fail to glow and ignite the gas. By measuring the voltage, the technician can determine if power is being supplied properly. If the voltage is present and within the appropriate range, yet the igniter does not light, this may indicate that the igniter itself is faulty and may need replacing. Conversely, if there is no voltage, the issue could lie elsewhere in the furnace electrical or control systems, such as a malfunctioning control board, wiring issues, or problems with the thermostat. This approach is systematic as it helps narrow down the root cause of the failure, ensuring that parts are only replaced when necessary, thereby saving time and resources.