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.
What controls the blower motor on the furnace?
A fan limit switch is a component of a furnace system that determines when the furnace blower assembly for hot air turns on and off. Essentially, this means that it determines when the hot air should be blown through your ventilation system. The fan limit switch also has two other functions.
Can bad thermostat cause blower not work?
An unlikely, but possible, cause is a bad thermostat. Try turning the Fan switch to the "On" position to see if the blower comes on. Watch the video. If the blower operates in the "On" position and does not operate when the air conditioner is running, you may have a bad thermostat.
What thermostat wire controls the blower?
Thermostat Green Wire (“G” Wire) Green wire is for the fan. Mini-splits have an indoor air handler with a fan; the power input that goes into the fan is regulated by the green or “G” wire.
Does thermostat control fan in car?
The fans are controlled either with a thermostatic switch or by the engine computer, and they turn on when the temperature of the coolant goes above a set point. They turn back off when the temperature drops below that point. Rear-wheel drive cars with longitudinal engines usually have engine-driven cooling fans.
What controls the blower motor speed?
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
Do all furnace blower motors have a reset button?
All furnaces are equipped with a reset button. They are generally red or yellow and are located inside the blower compartment. The reset button is a safety feature that will shut down the furnace when a problem is detected, often a hot or overheating furnace, before it trips the circuit breaker.
What can cause a blower motor to stop working?
In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.
Why is my blower fan not working?
If you see or hear the fan turn on, your blower motor is not the culprit. If the fan does not start, you have a wiring issue (circuit breaker trips) or motor problem (circuit breaker does not trip). While your thermostat may be at fault, only an HVAC technician can diagnose and remedy the issue correctly.
How does thermostat control fan?
Once the thermostat reaches your setpoint temperature, your central air system powers down and the fan shuts off with it. Setting the fan to on: The fan will run independently of heating or cooling. In other words, the fan is still operating even if the AC isn't cooling your home.
What happens if you wire a thermostat wrong?
Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.
What does black wire connect to thermostat?
This the Common Terminal, and usually, a blue or black wire is run to the transformer from this terminal to complete the circuit, and in some cases, provide power to the Thermostat. This terminal is found on thermostats designed to work with Heating Pumps and is used to power the defrost cycle on the heat pumps.
What controls the fan on a car?
On most modern cars, the cooling fan is controlled by the Engine Control Unit (ECU) which gets a signal from the coolant temperature sensor. If it's not working, the fan won't turn on when it needs to, which means the engine might overheat.
Does thermostat control radiator fan?
The thermostat opens and closes when there is a need to. How it works is simple. When the temperatures outside are cold the thermostat stays closed and the coolant stays in the engine. When the coolant reaches the working temperature the thermostat opens and the coolant circulates through the cooling system.
Should the thermostat fan be on auto or on for heat?
Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.
Where is the blower motor control module?
It's located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
Which are the three most common types of blower controls?
The three types of fans most commonly found in HVAC systems are the following: Axial fan. Forward-curved centrifugal fan. Backward-inclined fan.
What is blower motor relay?
In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay's reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.
Is there a fuse for the heater blower?
Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
What does blower motor reset button look like?
These blowers can be VERY hot. Step 4: Locate the reset button. This is usually on the side or the back of the blower motor. Often times, this button is red.
Why is my furnace running but not blowing air?
Blower Issues The most common reason for a furnace running but not blowing air is likely due to issues with the blower or blower motor. The blower is responsible for pushing air out of the registers and when it fails no air will come out.
How do you reset a blower motor switch?
Examine the exposed components in the furnace cabinet to locate the blower motor; look for a small silver box positioned toward the top of the cabinet. Mounted just above this box you should see a small round component with a raised red or white button at the center; this is the blower reset switch.
Where is the blower resistor located?
The blower motor resistor is usually extremely easy to access, but the hard part can be positioning your body inside the car to remove the part. The resistor is at the bottom of the HVAC housing or just behind the glove compartment.
Should you replace blower motor and resistor at the same time?
We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.
How do I test a blower motor resistor?
Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.
What does a thermostat control?
A thermostat is a device in the home that is connected to the central heating system and is used to control the overall temperature of the system by monitoring the ambient temperature in the home.
How do thermostats work with furnace blowers?
Thermostats have the ability to be wired to the furnace blower. This allows the homeowner to run the blower without the heat or air conditioning on. This is like having an air circulation system in the home. The air is taken back to the blower through the return air ducts to the furnace and is then returned to the home through the supply air ducts.
What is an HVAC blower motor?
Simply put, an HVAC blower motor is the component that turns on your system’s fan that pushes the hot or cold air out of the unit and into your home. Air heating systems such as electric and gas furnaces, air conditioners, heat pumps, and mini splits all utilize a blower motor to transfer this air.
What does the fan setting on a thermostat do?
So, what does the fan setting on a thermostat do? The fan setting on your thermostat turn’s the blower in your HVAC system on and off. You can set a blower fan to AUTO so that the blower turns on when the AC or furnace is running. An HVAC blower will continually run if you set it to ON through your thermostat.
What is a blower motor resistor?
The motor that runs the fan in the heating and air conditioning system in a car is called a blower motor. It's located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
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