Why does the blower on my furnace keep running?

If your fan limit switch is set to AUTO but the fan continues to run without ever stopping, you’ll need to call a professional. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced. Bad thermostat wiring.

Why is my furnace turning on but not igniting?

If your gas furnace initiates the start cycle but does not fire up, it’s likely because of a faulty, damaged, or dirty ignitor/sensor. This is a very common furnace problem—you can try to clean the sensor and replace the ignitor.

Why won’t my furnace blower shut off?

Quote from the video:
Quote from Youtube video: This is craig migliaccio from aec cyberstack. And today what we're going over is why a furnace blower motor continues to run and blow cold air all through the building. So even when the thermostat is

Can hear your furnace click on but it does not fire up?

The Pilot Light (Faulty Ignition Sensor) The pilot light or ignition sensor is usually the most common issue when your furnace will not ignite. This is typically the problem if you can hear your furnace click on but it does not fire up.

Why will a blower run on the on position and not on auto?

Other Blower Fan Won’t Run Problems

The fan will run and blow warm air but only in FAN or FAN ON mode – delivering heat – but NOT in AUTO mode. This is a bad temperature sensor in the unit; replace the fan limit controller.

How do you reset a furnace blower?

How to Reset an Electric Furnace

  1. First, turn off the power supply to the furnace by turning off the breaker in the circuit box.
  2. Locate the reset button on the furnace and press it to reset the furnace. …
  3. If the button is popped up, press it down.
  4. Return the cover to the blower compartment and turn the power on.

How do you know if your furnace ignitor is bad?

Your furnace won’t run: The most obvious sign that your ignitor is bad is that it won’t ignite, and this generally manifests itself in your furnace failing to run when you activate it. One word of caution, though: this can also be caused by other issues, some of which are electrical.

How do I know if my furnace spark ignitor is bad?

4 Signs of a Faulty Furnace Ignitor

  1. The Furnace Stops Running. When a furnace won’t run at all, check for a bad ignitor. …
  2. Your Furnace Blows Chilly Air. Unless you’ve set your thermostat to COOL, your furnace should not blow cold air. …
  3. Does Your Furnace Short Cycle? …
  4. A No Glow Ignitor. …
  5. We Can Replace Your Furnace Ignitor.

Where is furnace flame sensor?

A furnace flame sensor is a very basic part of your furnace. It’s located on the burner assembly and is just a thin metallic rod. It’s usually bent, and it sits just in front of the pilot flame inside the furnace.

Why does my furnace keep trying to start?

What causes the furnace to start then stop? Common causes of furnace short cycling include: Restricted airflow. Airflow can be limited through the system when an air filter is dirty, is not installed correctly, or a filter that is too restrictive is in place.

How do I clean my furnace flame sensor?

Quote from the video:
Quote from Youtube video: So if you have a situation like this what you have 90% of the time is just a dirty flame sensor. So we'll go through the steps on how to clean it. So the right side of the furnace.

How do you test a flame sensor?

Quote from the video:
Quote from Youtube video: And connect one of the probes. Coming off the meter to the wire that you just disconnected. You're going to stick the probe between the insulation. And the back of the clip.

How much should it cost to replace a flame sensor?

Flame Sensor

It stops your furnace from letting off large amounts of natural gas if it’s not working properly. If the sensor is bad, it won’t be able to sense heat and will turn the furnace off. The average cost to repair or replace a flame sensor is between $75–$200.

What symptoms would a furnace with a dirty flame sensor exhibit?

Signs of a bad furnace flame sensor are:

  • The furnace lights but then shuts down after a few seconds (short cycles)
  • The porcelain on the flame sensor is cracked.
  • The flame sensor is sooty or corroded.

How much is a typical current flame sensor current?

The current is very small usually less than 10ua (microamps) 10 millionths of an amp. If the flame sensor gets dirty clean it with steel wool not sandpaper. Any sand residue left behind when heated turns to glass and blocks the current flow.

Can a flame sensor be intermittent?

The flame sensor is a safety component that detects whether or not there is a flame in the combustion chamber. If this sensor is dirty, the dirt can cause the sensor to operate intermittently. When this happens, your furnace will most likely light, but because the sensor can’t properly detect if a flame is present.

How do you bypass a flame sensor?

We have a different solution:

  1. Remove the access cover on the furnace.
  2. Locate the flame sensor.
  3. Cut the power to the furnace.
  4. Shut off the gas control valve.
  5. Take out the flame sensor by removing the mounting screw.
  6. Examine the part to see if it’s compromised, either by damage or dirtiness.

What does furnace flame sensor do?

A furnace flame sensor works by detecting the presence of a flame within the furnace. The sensor is a short length of thin metallic rod that creates a small current of electricity in order to confirm there is fire burning within the furnace.

Can you clean a flame sensor?

Quote from the video:
Quote from Youtube video: Now there's the flame sensor. And all we have to do to clean this is just to take a little piece of Emery paper. And sand it slightly. So if you don't have any of the sand.

What is flame sensor made of?

A flame sensor is nothing more than a stainless steel rod partially encased in porcelain. By itself, it does nothing. There are no moving parts, no switches. When attached to a control module, the module sends out an A/C voltage to the sensor.