Is there a fan limit switch on a furnace?
In many models it also has a built-in safety control for the burner to shut off at higher temperatures if the burner’s inner control malfunctions. The switch is one of the easier devices and attachments on a furnace. The average consumer can both locate and set the fan limit control switch with ease.
Why does my AC fan not work at high speeds?
On the low speeds, the fan relay routes the voltage thru the resistor block. When you switch to high fan speed, the relay switches over to supply full voltage from the battery to the fan motor. Tester is right.
Where is the control switch on a Hunker furnace?
It should be located near the top of the furnace within the panel. Slide the cover off the control switch or lift it up. Inside you’ll see the switch itself sticking out along with a dial with temperature settings. Set the markers to the appropriate settings for your furnace. Check with your owner’s manual for suggested temperatures.
How are relays used to switch fan speeds?
Relays are not used to switch fan speeds, a resistor block is. Plus there are NO electronic commuted motors in a automotive application. This vehicle uses a resistor block to switch fan speeds. No relays involved in the lower speed circuit.
How does a high limit fan switch work?
A high limit setting, which turns off the heat source or burner if the furnace overheats to dangerous temperatures. A blower fan Manual ON switch is also included on many fan limit controls. This allows the blower fan to be set to run continuously.
What is the fan setting on a HVAC system?
The fan setting on your thermostat controls your HVAC’s system blower. The blower helps circulate hot or cold air throughout your home until the temperature on the thermostat is reached. There are two settings on your thermostat to control the fan – auto or on.
Where is the fan limit switch on a gas furnace?
The fan limit switch senses the temperature increase in the furnace. The fan limit control includes a sensor (not visible in the photographs) that projects into the supply air plenum – on gas furnaces this is typically an area above the furnace heat exchanger.
How does the fan on and off switch work?
On the switch shown, pushing the switch IN puts the fan in MAN or always ON while pulling the white switch OUT restores the fan to AUTO operation. – it will turn on or off according to the supply air temperature and the FAN OFF, FAN ON settings on the control.