Turn off the furnace at the wall control.
Test furnace gas valve.
Locate the gas valve.
Pull the wires off.
This one shows how to do a voltmeter check of the gas valve.
Take out the bolts in the service panel on the side of the furnace using a nut driver.
This video is part of the heating and cooling series.
How to check the furnace gas valve with a multimeter step 1.
Some gas valves cannot be checked with an ohmm.
Have the assistant set the dryer for high heat and turn the dryer on.
Sweep out any hair lint and foreign debris with a feather duster.
I will be checking various gas valves to see if you can check the continuity of the solenoid with an ohmmeter.
This one covers a simple way to find out if the gas valve is being energized on the newer gas furnaces.
Wait for the unit to cool if it has been in use.