My Heil Blower Motor Is Stuck on the Heater

Limit Switch

• The fan limit control switch, which is located on the furnace itself, may also have an automatic or "auto" setting and a manual setting that controls whether the fan motor runs continuously or cycles on and off. The manual setting will force the blower motor to run constantly. Consult your Heil furnace's owner’s manual for the exact location of this switch on your furnace.

Pressure Switch

• A pressure switch is designed to shut down a furnace if it’s not receiving good air flow required for combustion. Symptoms of a bad pressure switch can be the same as those for a bad blower motor. A pressure switch is a safety device that helps protect the heat exchanger so it doesn’t overheat. Never try to bypass it. Use a voltmeter to test the pressure switch. If you don’t get a reading of at least 24 volts, your pressure switch may need to be replaced.

Rollout Switch

• A rollout switch is another safety device designed to stop a Heil furnace from running if it senses temperatures of 350 degrees or higher. If the rollout switch is bad, the control board thinks the furnace is overheating and forces the blower motor to remain on. Use a voltmeter to test the rollout switch. You should get a reading of about 25.85 volts if the switch is good.

Problems

• If you don’t get a voltage reading when you test the rollout switch, you might have a leaking or stopped-up heat exchanger; call your service technician. A dirty evaporator coil, dirty filters or a slow blower motor can cause the limit control switch . If the blower motor is the problem, you should check the capacitor. A stopped up vent, a plugged tube between the pressure switch and the draft inducer, or a plugged hole on the draft inducer can cause pressure switch problems. If you have a Heil high-efficiency condensing furnace, the water drain line could also be stopped up.

Oiling

• Blower motors can become stuck if they need oiling. Many new furnaces have sealed motors that don’t require lubrication. However, if your Heil furnace blower motor has oil ports, it will need two or three drops of nondetergent oil specifically made for furnace blower motors. Lubricate your motor once a year. Never use an all-purpose or flammable oil since the blower motor operates under very hot conditions.