HVAC Troubleshooting Practice Test 2026 - Free HVAC Practice Questions and Troubleshooting Study Guide

A reading of 0 ohms or infinity ohms on older gas valves indicates a potential fault in the valve. A reading of 0 ohms suggests a short circuit, meaning there is an unintended pathway that allows current to flow freely through the component, which can prevent the gas valve from functioning correctly. Conversely, a reading of infinity ohms indicates an open circuit, meaning there is no continuity through the valve. This condition prevents electrical current from passing, which would also render the valve inoperative. Therefore, both readings signify issues with the gas valve that would lead to its failure to operate properly, confirming that the valve is faulty.

In the context of the other readings, while 50, 10,000, and 100 ohms might suggest varying conditions of resistance, they do not directly indicate a clear failure of the gas valve as definitively as the readings of 0 or infinity ohms do.