Can a blower fan work only when the thermostat is set to fan on?

Fan will work only when thermostat set to fan on. Thank you for the question, Anon, as it’s a common A/C, or heating fan operating problem that needs to be understood: I put it as “The blower fan runs only in the MAN-ON switch but won’t run on AUTO”.

How to troubleshoot a furnace blower that runs no heat?

You can avoid expensive repairs by troubleshooting furnace problems before calling a professional. The blower motor itself does not create the heat; rather it blows the heated air created by the furnace through the system’s ductwork. Start with the simple causes before moving to the more complex ones.

Why does my electric heater fan not come on?

If the electric heater fan comes on when you turn on the heater, but no heat seems to be coming out, you could have a blown circuit or there may be a break in the actual heater coil. Most parts can be ordered directly from the manufacturer and installed quickly and easily.

Why does my blower fan run only on auto?

I put it as “The blower fan runs only in the MAN-ON switch but won’t run on AUTO”. This problem can happen in both heating and cooling mode. Rule out bad fan motor or no power to fan.

Why is my air blower not running on a / C?

Usually if its that, the air does blow from the vents. FAN BLOWER NOT RUNNING ON A/C BUT RUN ON HEATER, and ALSO couldn’t turn on the FAN from the thermostat, Need help, Please My ac air blower went bad in my trailer but for the last 6 months it couldn’t keep up with temp l had it set on, will new one be able to keep up ?

What should I do if my electric heater fan is not working?

Replacing a circuit can be easy, whereas replacing or repairing the coil can be much more complicated. If the electric heater fan comes on, and you are not getting heat, it could be a blown circuit or resistor or a broken heater coil. You will want to open the case and start testing the circuits with the voltage regulator.

Why does my Furnace Fan only come on when the furnace is on?

It only has a 2 wires connected to it – a black wire and a white wire. The heating system is working fine, except that when the heater is not engaged and I turn the fan switch to ON the fan does not come on. It will only come on when the furnace is on. This must because a G wire is not hooked up.

What happens when the fan is not turned on?

More details are below. If the limit control is not working to turn the fan on when the plenum is warm, the plenum will continue to get hotter; as the burner remains on the plenum temperature will reach the HI LIMIT and a safety circuit in the limit control will turn the burner OFF.

Do you need to disconnect the fan and furnace wires?

If you have only two wires available, yes. Otherwise, you will need to disconnect the fan+furnace wire bonding, and use them manually each time. Verify that the cable ran to the box does not have any additional wires in the sheath… If not, you’ll need to pull new wires through. Not the best news :/ – Robert Lerner Oct 13 ’16 at 21:09

Where is the fan limit switch on a thermostat?

Your system probably has a manual FAN ON switch on the thermostat, or if not, there may be a FAN ON push pull switch right on the fan limit switch in the air handler. If you can make the blower run then we know the problem is not with the blower motor or drive belt or assembly and we’d go to step two.

Why does my Furnace Fan not come on?

1. Make sure that your furnace switch is “ON” the furnace blower compartment door is on and secure. Move the lever on the thermostat to the “ON” position. The fan blower should come on. If it doesn’t then you probably have loose or burnt wires in behind the relay or you may need a new fan relay or circuit board. 2.