Things You'll Need
Ruud household furnaces have both ignitors and flame sensors that produce the heat for the furnace. If there is a problem with the ignitor, the flame sensor will stop working and close down the supply of gas. If this is the case, the ignitor needs to be replaced. The ignitor is attached to a metal mounting bracket with two screws, and has two wires coming out of its end that are attached via a plastic plug-in connector to the oven.
Turn the electricity off to the furnace. Lift up the access door, and pull it out to remove it. The flame sensor and ignitor can be seen inside.
Pull out the plug-in connector from the socket by hand, and then remove the screws holding the ignitor to the metal bracket. Remove the ignitor.
Attach the screws of the new ignitor to the metal bracket, and push in the plastic plug-in connector into the socket. Replace the burner door, and turn the electricity back on.