If you were asked when the worst time for your furnace to break down would be, you would probably say it would be in the middle of a cold snap, and that is unfortunately a prediction that can come true for plenty of us.

Just as your car seems to always break down when you are miles from home and its pouring with rain, losing your heating and cooling system when you need it most is not a pleasant experience.

Don’t panic

The first reaction when your furnace won’t respond the way you want it to, is to reach for the phone and call for an engineer to fix the problem.

It might be that you need some professional assistance to put things right again but it is often best to not panic in the first instance and try a few simple fixes yourself before calling for assistance.

Work your way through a quick troubleshooting checklist, so that you can eliminate some more obvious faults.

Check your thermostat

First thing to try is often to check the thermostat and make sure it is set to the heating function and that the temperature set point is higher than the ambient temperature, which would normally click it into action when it is working properly.

You might also want to ensure that the fan is turned round to the on position or mode, just in case.

Power to the system

Gas systems still rely on electricity and your problem could be as simple as a lack of power to the heating system.

Check the circuit breaker to see if the circuit breaker has tripped and look for any signs of damage to the power cord or a poor connection, but don’t attempt to take apart any electrical components, especially if you are unsure what you are looking for.

Is the blower motor working?

You should find that the blower compartment on your furnace has an inspection window with a visible green flashing inside it.

If there is no light or the light is red, this could be an indication of an issue with the blower motor or it could indicate a problem with the control board, run capacitor or transformer.

Pilot light working?

Check to see if the pilot light is lit and if not, attempt to re-ignite it so that you have a flame that is lit and stays on as well as reaching the bottom of the thermocouple switch.

If the pilot light keeps going out each time you light it, the sensor could be dirty.

Is the condensate pan full?

Check to see if the reservoir in the condensate pan is full and needs draining.

If the pan is full, this will prevent the heating system from turning on. Arrange to drain the reservoir and also check the condensate pipe to see if you notice any blockages or problems which could be causing the loss of power to the pump.

Check your filters

Dirty filters are one of the most common causes of furnace problems and it is definitely worth checking your filters before calling someone out.

To work safely, always turn off the shutoff switch and turn the thermostat dial down as low as it will go, before you attempt to inspect or work on any part of your furnace.

Once you have ensured that your furnace is powered down, refer to your owner’s manual for specific instructions relevant to your model on how to inspect, remove and replace your filters.

If the filter is clogged, it will cause dirt and dust to restrict airflow. This will cause the heat exchanger to overheat and shut off quicker than it should do.

If you find the blower is still running but there is no heat coming out if it before you turned it off, replace the filter to see if this fixes the problem. If you aim to replace the flat filters regularly, such as every 4-6 weeks, this won’t be very expensive to do but it will help keep things running smoothly and should prolong the life of your system too.

Other fault-finding fixes to try include making sure that the chimney exhaust flue is clear of any debris and if your furnace comes on but a few of your rooms are cold, check to see if all the room registers are on and whether you have any blocked or leaky ducts.

Try some of these pointers before calling the repairman, as there is often a simple explanation why your system is not working properly. If you are not sure what the issue is, it is always best to call in a professional to sort it out.

Jayden Fraser is the DIY guy all his friends call when something breaks in their home, whether it be a broken washing machine, leaky air con unit or TV troubles. His handyman articles appear on DIY, home decor and lifestyle blogs.