furnace blower not working on auto

However it doesnt mean that you should limit your troubleshooting to the two areas. It can do this with a simple delay or by temperature set by the limit switch in the plenum.

How To Replace A Furnace Blower Motor And Capacitor

In AUTO mode the furnace will heat up but the fan wont run the heater then reaches the HI LIMIT and the system shuts down - the fan never runs.

. I replaced the limit switch L170-40 and still have the same problem. If your furnace blower fan is not working the fan motor is likely defective. The furnace ends up shutting down because it overheats.

You can take the cover off watch it work probe the voltages. If your blower isnt turning you most likely have a faulty thermostat. To ensure the capacitor is the issue you will need to test the capacitor itself before you replace it.

If there is no problem with the incoming power we can move on. Check to see if the thermostat is set appropriately. The furnace controls the fan because oil and gas heat is not instantaneous.

For heating applications a lower blower speed is used and the furnace selects it. The one for the ON position is a different speed. Everything goes as it should except when time for blower fan to come on.

Every furnace blower motor has a capacitor installed beside it to jump-start the motor. Alternatively you may have a wiring issue. If it has reset and allow time for a normal heating cycle.

The fan will run and blow warm air but only in FAN or FAN ON mode - delivering heat - but NOT in AUTO mode. Pressure switch is damaged. If it does then the motor is bad.

When the thermostat is set to auto and the furnace turns on automatically the burner ignites and the combustion air blower turns on. However after it heats up the supply air blower the main blower never comes on automatically. Our customer care team is available to help by phone or live chat seven days a week.

Check to see if the furnace circuit breaker has tripped. This is a bad temperature sensor in the unit. Up to 6 cash back RepairClinic has millions of replacement parts for appliances lawn equipment power tools and heating cooling equipment including washers dryers dishwashers refrigerators lawn mowers snowblowers furnaces and air conditioners.

Might not even be a relay. I checked this one with ohm tester. Take these three steps as soon as you realize that your furnace isnt working.

Sometimes that capacitor goes bad and it can cause your blower motor to not work properly. If set too low you may be cold but your furnace. See How to diagnose your blower problem.

However most people set the fan to AUTO for convenience. This video provides information on how to troubleshoot a furnace blower that wont run and the most likely defective parts associ. Make sure the furnaces onoff switch is in the on position and check to see if the circuit breaker controlling the voltage to the furnace has tripped or a circuit box fuse has blown.

This can be done quickly by yourself or by hiring a professional. It doesnt come on if in auto mode but if I put it in the on mode the blower comes on and I have heat. Sometimes the blower may run even with heating off.

Malfunctioning blower motor As mentioned earlier the circulation blower fan motor. Purpose of the Fan Center Relay. It could be the fanlimit switch as seen in the first picture.

Replace blower motorVerify the blower is operating and there is air being forced from the vent connector at the If the blower motor does not operate check for 120VAC at the on then the control module is receiving 120VAC and must work. The purpose of the fan center relay is to provide a low voltage control 24 Volts to control a relay that can be used to control two-speed blower motors and auxiliary circuits in heating or cooling equipmentMany of the newer furnaces do not have fan center relays but many of the older furnaces and some new furnaces still do. If not then the board is bad and not getting power to the heat winding of the blower.

In order to avoid a blast of cold air the furnace controls the fan. If your furnace blower motor hums but does not start this is most likely due to a faulty capacitor. You could look in the furnace and locate the blower wire that is on the heat terminal of the board and then find one that is on park and switch the two and see if the blower runs.

You see even after you turn on the furnace it will not produce heat until the thermostat calls for heating. Remember capacitors are not long-lasting components they do die with time and you need to replace them with new ones. Furnace blower not running.

Replace the fan limit controller. There is another limit switch in the blower area L140-40. The problem is still the same however.

These two are the most common reasons why the furnace blower may refuse to turn. Fan leads are 120V thermostat wires for limit are usually 24V.

Furnace Blower Not Working How To Check It Youtube