Why Is My Furnace Blowing Cold Air When The Heat Is On?

Your furnace may be blowing cold air because the filter is too dirty. A dirty air filter blocks airflow over the furnace’s heat exchanger, causing it to overheat. When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack.

Why is cold air coming out of my vents when the heat is on?

Your Air Filter Is Dirty
Clogged air filters could be causing cold air to blow out of your vents. A dirty air filter can block airflow over your furnace’s heat exchanger, which can cause it to overheat.

Why is my furnace running but no heat?

Dirty filters are the most common cause of furnace problems. Dust and dirt restrict airflow—and if the filter gets too clogged, the heat exchanger will overheat and shut off too quickly, and your house won’t warm up. If the blower is running but no heat is coming out, replace the filter.

What would cause a furnace not to kick on?

The Pilot Light (Faulty Ignition Sensor) The pilot light or ignition sensor is usually the most common issue when your furnace will not ignite.Put the front panel back on, turn on the gas, and then turn the furnace back on. Turn up the temperature on your thermostat to see if your furnace will now fire up.

Where is the reset button on a furnace?

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.

How do I get my heat to kick on?

Inspect Your Thermostat – First off, make sure your thermostat is set to the “Heat” or “Auto” setting. If that doesn’t start warm airflow, raise the temperature to the highest possible setting. Wait a few minutes to see if that sets the furnace in motion.

How long should it take for a furnace to kick on?

Your furnace should start up within five minutes of you turning on your thermostat.

How do you know a thermostat is bad?

7 Signs You Need to Replace Your Thermostat

1. Your HVAC Keeps Turning On or Off.
2. Faulty Thermostat Readings.
3. Suspiciously High Energy Bills.
4. Constant Temperature Shifts.
5. Thermostat Is Too Old.
6. Thermostat Fails to Respond to Changed Settings.
7. Your HVAC System Short Cycles.

How do you reset furnace blower?

How to Find and Reset your Furnace Motor Blower

1. Step 1: Turn off the power to the furnace.
2. Step 2: Remove the blower compartment cover.
3. Step 3: Make sure the blower is completely cooled off.
4. Step 4: Locate the reset button.
5. Step 5: Press the button in (assuming that this is your issue and that the button has popped).

Why does my furnace turn on and off every few minutes?

Dirty or faulty flame sensor
If your furnace turns off after a few minutes, there is a good chance it is caused by a faulty or dirty flame sensor. This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again.

How many times can I hit the reset button on my furnace?

Don’t hit “reset” more than twice. The process pumps oil into the burner chamber, where it can accumulate if you have no ignition. Then when the furnace finally does start, it can do so explosively. So if the button won’t reset, or quickly pops up again, it’s time to call a professional repair service.

Can you vacuum your furnace filter?

Vacuuming your furnace filter will remove the build up of dirt and dust that impedes airflow through your system and increases your cooling systems run time. Vacuuming your furnace filter will not likely extend the life of your filter though.

Can you clean home air filters?

Some air filters — permanent and semipermanent models — can be cleaned as part of regular HVAC system maintenance and replaced for continuous use.At regular intervals, you must remove it from the HVAC cabinet, throw it away, and install a fresh filter. Disposable air filters shouldn’t be vacuumed or moistened.

Will a bad thermostat cause the furnace not to work?

Malfunctioning thermostat: A faulty thermostat can lead to problems with the fan or comfort levels. The furnace doesn’t heat at all: A furnace that doesn’t perform its main task may have problems with the thermostat setting, power, gas or the pilot light.

Where is furnace filter located?

blower compartment
The furnace filter is usually located inside of the blower compartment, where the return air enters the blower compartment. Most units have built-in furnace racks. The large metal furnace compartment contains a filter and blower.

How long should a furnace run daily?

Energy Savings
Most systems should run about 2-3 cycles per hour. How long should the furnace or AC run in a given cycle? Typically 10-15 minutes in mild weather. The closer you get to the max design temperature in heating (0 Degrees) or cooling (90 Degrees) the longer the run cycle will be.

How many hours should furnace run in winter?

Running 10 to 15 minutes per cycle seems acceptable. So is running as long as 20 minutes. Even running every seven or eight minutes may not be a problem, as other factors could lead to more frequent cycling. Outside temperature, for example, could contribute to how fast or slow the furnace cycles.

How many times should furnace cycle per hour?

On average, furnaces should kick on and turn off anywhere from three to eight times per hour. However, if your furnace turns on and off more frequently, don’t assume the furnace is short cycling just yet.

How do you tell if you need a new thermostat in your house?

Signs You Need a New Thermostat

1. Heating or cooling system will not turn off or on.
2. The temperature reading is incorrect.
3. Recent spike in your energy bill.
4. Frequent temperature fluctuations.
5. Thermostat is 10 years old or older.

How do you test a furnace thermostat?

How to Test Your Furnace Thermostat

1. Step 1: Reset the thermostat lower or higher.
2. Step 2: Make sure the thermostat is ON.
3. Step 3: Check the wiring.
4. Step 4: Turn breaker back on.
5. Step 5: Reexamine wires.
6. Step 6: Wrap wires together.

How do I test my home thermostat?

How to Test an Old Thermostat

1. Step 1: Turn off HVAC power. This can be done by switching the furnace to the off position if your system has an on/off switch.
2. Step 2: Remove thermostat cover.
3. Step 3: Remove wires from terminals.
4. Step 4: Turn the HVAC power back on.
5. Step 5: Test other wires.