5 Things to Check If Your Furnace Fan Blows Cold Air

Is your furnace blowing cold air? Or is it blowing warm air at short intervals? Perhaps it’s not blowing any air at all? Before you call for repairs, check your furnace. Checking your HVAC system for the following can save you the cost and effort:

  1. Air Filters – Clogged filters can block airflow, and should, therefore, be regularly cleaned. During months of heavy use, such as in the middle of winter, air filters should be cleaned as often as once a month. Certain types of filters may have too fine a mesh that could impede airflow even when clean. If you’re unsure of what type of filter to purchase, consult your trusted HVAC technician.
  2. Air Ducts – Go through all the rooms in the house and check whether some of the rooms are getting warm air. If this is the case, check the air ducts that lead to the other rooms. Look for long uninsulated runs, damaged insulation or leaks in the ductwork. Insulation can be repaired or replaced at relatively low cost.
  3. Dampers – Dampers control the amount of warm or cool air that gets into the room. Its moving parts may accumulate dust and dirt that could hamper its operation to the point where it might not open when needed. Dirty dampers may require professional cleaning due to its location within the ducts.
  4. Air Conditioner – While most of today’s heating and air conditioning systems are controlled in a single system, more than a few homes still have independently controlled heating and cooling. If your air conditioner is part of such a system, make sure it’s not turned on by accident. Likewise, check the thermostat if it’s set to cool.
  5. Fan Limit Switch – Most furnaces have a fan limit switch, which allows user-configured minimum and maximum temperatures. Depending on the type of furnace, you may need to remove a panel to access this component. Move the upper limit of the fan limit switch to a few degrees higher, and ask someone to check if the rooms are getting warm air. If they are, wait a few minutes before setting the upper limit back. It should continue blowing warm air as normal. If not, then the fan limit switch may be faulty and will require replacement.

Is Your Furnace Fan Still Blowing Cold Air?

If your furnace needs repair, call McMaster today at (949) 481-7995. You can also fill out our contact form to schedule a free estimate. We serve Orange County and the surrounding areas.