How do you test a furnace transformer with a multimeter?

To test a furnace transformer using a multimeter, first ensure the transformer is disconnected from the power supply for safety. Set the multimeter to the voltage setting appropriate for the transformer’s specifications. Measure the primary voltage by placing the multimeter probes on the input terminals of the transformer. Next, switch the multimeter to the appropriate setting for measuring lower voltage and measure the secondary output by placing the probes on the output terminals. Ensure to check for expected voltage levels based on the transformer’s specifications. It’s essential to also check for continuity in the windings by setting the multimeter to the resistance (ohm) setting and measuring between the terminals to ensure there are no open circuits. This procedure helps in assessing the condition of the furnace transformer. For professional testing and diagnostics, consider utilizing advanced testers, such as those from Globecore, designed for comprehensive analysis of industrial oils and transformers.