The gas furnace blower motor is usually controlled by
the same board
, which controls the burners and ignition. … These variable-speed blower motors can run at different speeds as determined by the control board and the engineering which went into the control board.
What are the three main controls on a gas furnace?
The furnace gas valve operates by electromagnets. The primary valve — also known as the safety valve — supplies gas to the pilot light. The second
valve —
also known as the main valve — allows gas to flow to the burner trays. The thermocouple (or thermopile) generates the power holds the safety valve open.
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.
What device turns on a blower motor during the heating mode?
The high limit switch
is also an extremely important safety device inside your furnace. When the furnace begins running, the switch's role is to turn on the blower fan when the supply air gets hot enough.
Locate the reset button on the furnace and press it to reset the furnace. It is usually located
inside the blower compartment on the side of the blower motor
. Be cautious as the housing may be hot. If the button is popped up, press it down.
What happens when blower motor relay goes bad?
If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may
cause the blower motor fuse to blow
. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.
Is there a fuse for blower motor?
The blower motor is powered by a fuse-like device called
a relay
. If your heater or air conditioner does not blow air through the vents, this could indicate that the blower motor fuse has probably blown. While replacement is easy, the exact location of your blower motor fuse may vary from vehicle to vehicle.
Why do gas furnace efficiencies jump from 80% to 90 %?
Why do gas furnace efficiencies jump from 80% to 90%? Efficiencies
over 80% cause condensation
but the flue gas is still too hot for PVC vent pipe until the efficiency reaches 90%.
How long do furnaces usually last?
How Long Does a Furnace Typically Last? The average lifespan of a gas furnace is
approximately 15-20 years
.
What is the third component in the furnace called?
Forced draft
. The third category of furnace is the forced draft, mid-efficiency furnace with a steel heat exchanger and multi-speed blower.
How do I adjust the fan control on my furnace?
For a general guide, set the
two lowest ones (from the furthest left) to 100 and 130 degrees
to control when the fan comes on and goes off. The third marker should be set around 200 degrees as a safety shut-off for the burner.
Is the fan supposed to turn when the heat is on?
The fan on your unit should
spin when you want air in your house
and shouldn't spin when the temperature has reached the desired temperature set on your thermostat.
Why does my furnace fan not shut off?
If your furnace fan won't turn off, you most likely have one of these 3 problems: Your
furnace fan limit switch is set to “manual override
” The fan limit switch is faulty and needs to be replaced. There's a problem in your thermostat wiring.
How do I know if my furnace blower motor is bad?
- Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem. …
- No Airflow At All From Vents. …
- Skyrocketing Energy Bills. …
- Strange Noises When You Turn on the Heat. …
- Overheating Blower / Weird Smells.
What can cause a blower motor to stop working?
In a situation where the motor doesn't work on any speed, the most likely causes are:
a blown power supply fuse
, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely.
The Reset button is usually located
on the back of your device
but can be found on the bottom in some cases.
