Why Is My Heater Blowing Cold Air?

I awake in the middle of the night freezing!  My nose feels like an ice cube, goosebumps are popping out on top of each other, and my toes feel like Antarctica icebergs attempting to break off my feet.  I might never see them again!  Something is definitely wrong. You very may well have a problem with your heating system, according to a top provider of HVAC in Houston, Superior HVAC.

I explode out of bed, land in my slippers, shake the frost off my once warm and comfy housecoat, and rush to the thermostat.  It reads 47 degrees inside, 18 degrees outside, and it is dropping!  No wonder I’m an icicle.

I hear the furnace running and it sounds perfectly normal.  I run to the closest heat register and to my horror, I am blasted with air so frigid my teeth nearly crack!  What should I do?  Teeth chattering like castanets, I fire up the computer to find out.

 

Possible problems to consider

Most HVAC businesses suggest checking several items yourself to determine if you need to call a professional heating, ventilation, and air conditioning (HVAC) service.  Here are six easily accomplished things to check.

1. First and foremost, check your thermostat. It should be set to “Auto”, not “On”.  The On setting means the fan in your unit will run continuously.

2. Next, check the air filter. When clogged and dirty, it can cause your furnace to overheat and switch off the      ability to create hot air.  After changing the filter, you may need a professional to help restart the heating unit.

3. Check whether the pilot light has blown out. Try to re-light the pilot.  Be sure to follow the instructions            that came with your unit, or follow instructions you find on the Internet.  If the pilot light will not ignite,            the problem may be a faulty ignition switch.

4. If your furnace is relativity new and high efficiency, it will have a drainage line because creating heat also        creates water. If the drainage line is clogged, your heater will shut off its heat making ability.

5. Keep the area around your heater or furnace clean and clear. Dirt and debris negatively affect your                  heater’s ability to function well.  The unit needs clean air and a cleared space.  Vacuuming regularly will                do wonders for the condition and wear of the air filter, as well as the operation of your heating unit.

6. Try resetting your circuit breaker and as a last resort, make sure you paid your gas bill!

 

What problems require a professional HVAC service?

If none of the above issues applies to you, what else can the problem be?

The unit’s flame sensor might be dirty.  If you cannot relight the pilot, this may be the reason.  You cannot fix this problem yourself because the gas burner must be taken apart to access the flame sensor.

While you cannot clean the flame sensor, you can assess the flame if you have one.  Check to see if the flame is blue and even.  It is the indicator of a clean flame sensor.

Another problem might be your ductwork.  If it is damaged, clogged, or has leaks, it can be invaded by cold air.  If this is the case, you may need a specialized air duct cleaner to fix these issues, although some HVAC businesses may offer air duct repair along with the repair of heating issues.

While your air ducts are being repaired, you might want to consider having them cleaned at the same time, particularly if they have been emitting rattling, squeaking, or grinding sounds.

These are all signs something could be amiss.  Be sure to ascertain whether your HVAC servicer cleans air ducts as well.  Cleaning air ducts requires specialized training, machinery, and environmental practices.

The furnace blower motor should be oiled once per year. This can be an easy DIY project.  It is not one I would care to address because the blower motor assembly needs to be accessed, then removed from the unit.

There are several steps to the process.  If you are handy with mechanical things, you can find the directions in this e-book listed as “Problem 7”.

Furnaces and heaters are required to have high limit switches.  If this switch does not work, the furnace will not ignite and light up to create heat.

A bad ignition switch could also cause the furnace fan to blow continuously and could quickly burn out the fan motor.  Only a professional can install a new switch.

If your furnace is blowing cold air and cycling rapidly off and on, the problem’s first indicator could be a dirty air filter.  If this is not the case, the problem might be exhausted or broken fan belts or a problem with the unit’s motor.

I am happy and comfortably warm once again.  After checking the initial six items, I discovered my thermostat was accidentally set to “On”.

I moved the setting to “Auto” and the heater is doing its job once again.  I think my toddler may have toggled the switch while I was talking on the phone and holding him on my shoulder at the same time.

Perhaps this is an indicator he will grow up to be an HVAC man!