Disclaimer: Due to the dangerous nature of working with electricity, we highly recommend hiring a qualified expert with the training and tools to help troubleshoot and install replacement parts safely. This information is not intended as a comprehensive guide. If you choose to perform any troubleshooting or replacement yourself, you do so at your own risk. Remember to ALWAYS disconnect the appliance from its power source before disconnecting any wires or attempting service tasks.
What is Continuity?
Continuity indicates whether a circuit continuously conducts electricity, indicating a closed circuit, or if the flow is interrupted, indicating an open circuit. A continuity test is a quick and simple method to confirm whether the circuit allows the electric current to flow.
Most multimeters will have a dedicated setting to test continuity. On this setting, you will hear a “beep” tone if the circuit is complete. The absence of any tone indicates an open or interrupted circuit. The icon on your multimeter for continuity will look like the ripples of a sound wave.
Continuity in stoves and fireplaces:
Performing a continuity test helps to identify whether a part in your stove or fireplace is conducting the electricity it needs to do its job. This test works on any electronic part; however, it is especially useful on fuses and snap switches.
How to measure continuity:
Warning! Remember to unplug the system from its power source before checking for continuity.
- Set the multimeter to ‘Continuity’ mode.
- Touch the probes of the meter together. The multimeter should make a tone.
- Now touch the probes of the meter to the electrical connection, leads, or terminals of the part. If a conductive path is formed, you will hear the tone again. If the path is broken, you will hear no sound.
Tools you may need:
- The owner’s manual for the stove
- Wiring diagram
- A screwdriver set
- An ohmmeter or multimeter
- Needle nose pliers
- Lighter or hair dryer
Example #1: Fuses
A blown fuse may not always change in visual appearance. Performing a continuity test becomes necessary to verify whether the fuse is intact. Turn off the stove or fireplace and remove the fuse. Touch the probes of the meter to each end of the fuse. A complete circuit will create a “beep” tone, but no tone indicates that the fuse does not conduct electricity and is broken.
Example #2: Igniter Wires
If your pellet stove igniter is receiving power from the control board but does not heat up, you can start by verifying that the wires are not damaged. Be sure to unplug the stove from the wall before disconnecting any wires. Remove the igniter from the stove and touch the meter probes to the ends of the igniter wire. No tone from the multimeter indicates the conductive path through the igniter wires is broken, and the igniter should be replaced.
Example #3 Snap Switches
Snap switches sense temperature from the stove or fireplace and should snap open or closed when the appliance reaches the appropriate temperature range. As these switches age, they may weaken and become stuck open or closed. You will need to know whether the switch in question is usually open or closed. Remove the switch from the stove, and brace it with a pair of needle nose pliers. Touch the probes of the meter to the posts of the switch.
Normally Closed – the circuit should be complete; there should be a tone.
Normally Open – the circuit is not complete; there should be no sound.
If your switch(es) passed the first test, remove it from the stove and heat the front (metal disc) with a heat gun, a lighter, or a hair dryer while holding the probes on the posts. As the switch heats, there should be a "snap" sound, and the multimeter should display the opposite reading from when the switch was cool.
Normally Closed: Once heated, the switch will open and there should now be no connectivity.
Normally Opened: Once heated, the switch will close and there should now be connectivity.
If the switch does not function as described above, the switch is faulty and should be replaced.