There is nothing worse than your furnace conking out in the middle of winter.  Diagnostic repairs, or worse replacement, can cost far more than just simple maintenance.

Below are 5 of the most common furnace issues that you may run across with your HVAC system.

1.    Cracked Heat Exchanger

A cracked heat exchanger causes the air from the furnace blower to interfere with the flame, which causes it to flutter or go out, this then trips a safety switch and shuts down the furnace.  This means there is no heat blowing at all.

Solution:         Call for service.

Prevention:     Routine, annual maintenance.

2.    Slipped/Frayed Blower Belt

Improper belt tension can cause a slip.  An older or uncared for belt can become frayed.  Both issues cause the belt to become loose and will make squeaking/squealing noises.  This also causes the fan to stop working properly, thus not heating your home properly.

Solution:  Call for service, the repair can be as easy as tightening the loose belt, replacing the belt, or a more serious repair or replacement if it has been an ongoing issue.

Prevention:  Routine, annual maintenance.

3.    Malfunctioning Thermostat

Older thermostats can have issues with aging wiring or dust accumulation.  Additionally, extreme temperature changes, batteries, or other issues can cause a thermostat to stop communicating with the HVAC system and causing heating issues in your home.

Solution:         Replace an old thermostat with an updated, programmable thermostat.  This can be a DIY project, or if you are not too handy a professional tech should be called in to make the switch.

Prevention:     Make sure batteries (if required) are changed each season, upgrade an old unit.

4.    Frequent System Cycling

If your furnace is running in short, frequent cycles you may have an issue.  The most common cause of frequent furnace cycling is a dirty air filter.  The heat exchanger needs air blowing over it to prevent overheating, if the filter is dirty this is limiting the air needed to keep the exchanger from overheating and the furnace from shutting down  I addition to harming the furnace, the frequent cycling will also result in higher utility bills.

Solution:         Change the air filter.

Prevention:     Change the air filter every couple of months, monitor your filter to see how often you should change it based on your needs and schedule routine, annual maintenance to keep the HVAC system clean.

5.    Limit Switch Problem

The limit switch is located under the furnace’s supply plenum (the air distribution box attached to the supply outlet of the HVAC unit that heats or cools the air to be distributed throughout the house).  When the plenum reaches the desired temperature the limit switch sends a signal to begin running and delivering the warm air throughout your home.  If the limit switch’s sensor becomes dirty it can stop working properly and can either trip the switch prematurely or not at all and warm air will not be delivered to your home.

Solution:  Call for service to clean the sensor or replace the switch.

Prevention:  Keep the furnace filter clean and schedule routine, annual maintenance.



If you need help with a furnace issue, the professionals at TR Miller Heating & Cooling are here for you!  We service any make and model unit, we have 24 hours a day, 7 days a week service. Grab our special savings for furnace repairs on our Coupon page and schedule your service appointment.


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