Furnace Problems Troubleshooting Guide

Presidential Heating & Air Conditioning

Gaithersburg HVAC Contractors


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Should You Try to Fix Your Furnace Problem Yourself?

Man fixing FurnaceKnowing how to troubleshoot your furnace when something goes wrong can get the heat back on fast in the middle of winter. There are several things you can do before you call the HVAC technician for help. If you are able to fix it yourself, you don’t have to wait in the cold for the HVAC repairman. Doing it yourself can also save you time and money.

On the other hand, if you take the simple steps set out below, and the furnace is still not operating correctly, you are better off calling a professional to do the job. Attempting to handle the repair yourself and doing it wrong can cause a lot of damage to your heating system. You could end up spending even more money to repair it than you would have initially.

Ideally, you know how to troubleshoot the most common furnace problems. Knowing how to make those minor repairs will save you time and money. It will also help you recognize when you need to call in the professionals.

Below are eight simple things you can do to troubleshoot some of the most common furnace problems:

Check Your Breakers and Shut Off Switches

Circuit BreakerIt’s not that unusual for the problem to be a tripped circuit breaker or a shut-off button that has been switched off. Make sure all power switches are “on.” The furnace power switch is typically located on the furnace itself or on a nearby wall. Flip the switch and see if power returns to the furnace.

Also, check the front panel covering the blower. In some models, you need to make sure the panel is shut tightly. A switch under the panel needs to be depressed before the furnace will turn on.

If you have a gas furnace, look for a gas valve on the gas line. It may have been turned off by someone who neglected to turn it back on. If you find a handle that’s perpendicular to the gas pipe, turn it parallel to the “on” position.

If you have an older model furnace, check that the pilot light is still lit. If you have a newer model, it probably has a system with flashing lights that indicates the furnace’s operational status. A sequence of flashing lights or the numerical code can tell you if the system is getting power or has a mechanical or technical problem that is interfering with its proper operation. Refer to the furnace’s operation manual or access panel for the key that explains the code’s meaning and recommended solutions.

Check the Thermostat

ThermostatRoughly one-quarter of furnace repair calls turn out to be problems with the thermostat, not the furnace. Make sure the thermostat is operating and the settings are properly set. When more than one person resides in the house, it’s not unusual for someone to change the settings. Make sure the “heat” switch is in the “on” position. If your blower won’t stop running, make sure the fan setting is not stuck in the “on” position. Switch it to “auto.”

Make sure the temperature setting is set at the temperature setting you prefer. If you have a programmable thermostat, check the other settings to make sure the thermostat is communicating properly with the furnace.

You can also bypass all of the program features by setting it to “manual” and “heat.” Then adjust the temperature to at least 5 degrees higher than the current room temperature and listen for the furnace to come on. If it does, your thermostat is probably faulty and may need to be replaced.

You can also open the thermostat and gently blow out any dust or dirt that has accumulated over time. Finally, if the thermostat has a battery, replace it.

Change the Air Filters

Air FiltersOverly dirty and clogged air filters can cause your furnace to malfunction. Dirty filters block airflow, which causes the heat exchanger to overheat and shut off before your house has a chance to warm up. A dirty filter can cause soot to build up on the heat exchanger, which causes two problems. The soot impairs the operating efficiency of the furnace, and, over time, it can shorten the heat exchanger’s life. Change the air filters monthly.

Clear the Drain Lines

It’s not unusual for drain lines to become clogged. If your furnace is a newer model, be aware that high-efficiency furnaces can drain off several gallons of water a day in the wintertime. When drain lines become clogged, the furnace will shut down.

Flushing the drain lines is easy. Simply remove the hose, fill it with a mixture of 25% bleach and 75% water. Let it sit for a few minutes, and then rinse it well.

Clear Debris from External Components and Vents Outside Your Home

Dirty VentCheck any components and vents located outside your house. Make sure there is no debris or object interfering with operating components or blocking vents, intake openings, or exhaust vents. Clean or replace any mesh covering the pipe openings. If you see ice clogging one of the pipes, your problem could be somewhere inside the system. You will need to call your HVAC professional to diagnose this problem.

If you have a heat pump, make sure nothing is building up on the fins of the outdoor compressor unit. It is a good idea to hose it down carefully before the cold weather arrives. Clean off the dirt and debris.

Contact Presidential Heating and Air for More Information

Before the cold months arrive, you should have an HVAC expert inspect your heating system. The HVAC expert will inspect your furnace and clean the components. If new parts are needed, it is a good time to replace them. An inspection by a professional HVAC technician can often detect lurking furnace problems and repair them before they become major repairs. Contact Presidential Heating and Air to schedule an inspection of your furnace before winter sets in.

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