What Should You Do if Your HVAC System Isn't Pumping Out Heat for Your Home?

Lady feels a cold radiator when heat is out - Thomas & Galbraith Heating, Cooling, & Plumbing

When you wake up or walk in to no heat at home, your first priority is to get your heating system back on. What do you do? Do you call your HVAC company, or is there something you should try first?

Thomas & Galbraith’s No Heat Checklist shows you exactly where to check and what to do if you have no heat at home. Try these heating system troubleshooting steps first, then if your heat does not come back on, give us a call. Our NATE-certified heating technicians are available around the clock to tend to your heating emergencies, keeping your family safe and cozy throughout the winter season.

What to Do When You Have No Heat

A wide range of problems leave Cincinnati homeowners with no heat – some are serious and require professional help, but others are relatively minor. Minor problems are often solved with a bit of troubleshooting, which we discuss below. 

Our No Heat Checklist explains the steps you should take prior to making the call for heating service. Many of these steps apply to all heating systems, including furnaces, heat pumps, and boilers, but there are a few specifics based on system type. 

1. Check Your Thermostat

The thermostat is the control that communicates with your heating equipment and tells it when your home needs heat. Often, no heat in the home is a result of thermostat issues, whether they be true malfunctions or errors in settings. Whenever you notice no heat, check your thermostat first for troubleshooting.

  • Make sure your thermostat is on – the display should be on as normal. If it’s not, there could be a power issue. Dead batteries or an interruption in a hardwired thermostat’s power source stop the stat from communicating with your heating system entirely, thus no heat. Change the batteries and/or check your electrical panel to ensure the breaker is not tripped – reset it if needed. At this point, your thermostat should come back on – if it doesn’t, call for service because there is an issue with your thermostat.
  • Once you verify thermostat power, verify its settings. It needs to be set to heat mode – if it has been accidentally set to cool, you get no heat. Also check the fan settings, as errors here often produce a situation where the heating system appears to be running but only cold air comes from vents. The fan needs to be set to auto, so it only runs when the heating system does. If it is set to on, it runs all the time and blows cold air when the heating system is not cycling.
  • If you have a programmable thermostat, make sure all settings are programmed to the correct date and time, so you get heat when you expect it. Check that the hold or vacation mode have not been turned on, which interrupt your regular schedules.
  • For a heating cycle to start, the thermostat needs to be set higher than the room temperature – this signals the thermostat to tell your heating system to start. Adjust temperatures higher than the current temperature in your home to see if a heating cycle starts. If it does not, continue troubleshooting.

2. Close Access Panels

Furnaces and air handlers are enclosed in a metal cabinet which holds its components. The cabinet has access doors so a technician is able to access the system’s interior. In some models, these access doors must be firmly shut or else the system does not run. Check your indoor heating equipment’s exterior and make sure its panels are secure and that none have fallen off or have come loose. If there are loose or removed panels, replace them and see if the system is now able to start.

3. Check Electrical and Switches

Your heating equipment needs electricity to operate or else no heat is produced. You need to verify the system has power, at both the electrical panel of the home and the systems’ on/off switches.

  • Locate the circuit that runs your HVAC equipment – there may be more than one. See if the breaker on this circuit has tripped or if the fuse has blown, if your home uses a fuse box. Reset tripped breakers and replace blown fuses as needed.
  • Locate the on/off switches on your HVAC equipment. An indoor furnace or air handler has one on its exterior or on the wall nearby. The outdoor heat pump’s on/off switch is likely located on the wall of your home where the refrigerant lines enter. Make sure these switches are set in the on position.

4. Verify Open Airflow

Central furnace and heat pump heating systems need plenty of airflow to work properly. When airflow is blocked, potential overheating is a cause of no heat, because the system’s safety controls shut it down. Two common causes of airflow blockages homeowners should troubleshoot when they have no heat are air filters and vents.

  • Find your filter compartment and remove the access door if applicable.
  • Remove the filter and inspect – if it is filled with contaminants, throw it out and use a fresh filter.
  • Insert the filter into the filter compartment following the airflow directional markings on its frame. 
  • Make sure the filter is fully inserted and fits properly into the compartment.
  • Replace any access doors that were removed.

Closed or blocked vents throughout the home also cause heating systems to overheat and turn off. Inspect vents and return air grills in each room of your home – all vent louvers need to be open and all vents and grills must be unblocked by rugs, furniture, and other items. 

Once you perform these no heat troubleshooting steps, give your heating system some time to lower its temperature and see if it comes back on. If you still have no heat, check these items that are specific to your type of heating system.

Check Fuel Supply

If you have a furnace or boiler that uses natural gas, heating oil, or liquid propane, you must have adequate fuel on hand or else you receive no heat. These steps walk you through some troubleshooting for your heating system’s fuel supply.

  • If you have a gas furnace, make sure the nearby gas valve is open. Check that your utility service has not been interrupted.
  • If your furnace uses a pilot light, make sure it produces a flame. If the pilot light is out, turn off your gas supply for 10-15 minutes, then follow the instructions in your owner’s manual to relight it. Never try to relight a furnace pilot light if you are able to smell gas in the area.
  • If you have oil or liquid propane heating equipment, make sure the fuel storage tank has an adequate supply of heating fuel – you may need a refill, which has caused no heat in your home. Check the valves on the tank to make sure they are open and sending fuel to the heating equipment in your home.

Check for Ice on a Heat Pump

A home’s exterior heat pump unit has the potential to ice over during the winter months. Heavy ice prevents heat transfer, which results in no heat. An iced-over heat pump is an issue that needs fixed right away to avoid further damage to the equipment.

It is normal for a heat pump to accumulate a bit of frost during the winter, and it has a built-in defrost cycle to handle this. Defrost runs the system in cooling mode periodically to send heat to the outdoor coils and melt frost. Unfortunately, defrost is not very helpful when ice accumulations on the unit are heavy.

Look at your outdoor unit – if there is ice on its exterior, follow these instructions to help it thaw.

  • Disconnect power.
  • Pour warm water over the equipment to melt ice.
  • Gently chip away ice if possible. Never use sharp items or a great deal of force or you could damage the system.
  • Clear debris from the unit’s exterior, including snow, lawn clippings, leaves, sticks, vegetation, and outdoor items stored nearby.
  • Inspect your gutters and make sure a gutter leak is not allowing water to drip down onto the heat pump and freeze.

If your heat pump is heavily iced over and does not thaw, call us for heating repair. We dispatch NATE-certified heat pump technicians who thaw your system and find the cause. Repairs are performed so you don’t have to suffer from no heat any longer.

Inspect Boiler Condensate Pipes

A hot water boiler’s condensate pipe is also prone to freezing in the winter. When ice forms from the condensation that exits the system, condensation backs up and the system shuts down, which leaves you with no heat. Ice must be cleared away so your boiler runs properly.

  • Find the location of ice buildup – it is usually at the condensate pipe’s end or in pipe elbows or bends.
  • Pour hot water down the pipe until ice melts. Hot, not boiling – boiling water may crack the pipe.
  • A heat blanket may also be used to melt ice buildup – wrap it around the pipe until it thaws.
  • Reset your boiler before use.

Still Have No Heat? Call Thomas & Galbraith!

If you still have no heat after you work through the No Heat Checklist, give us a call. Our NATE-certified technicians perform quick and reliable heating repairs for all types, makes, and models of heating systems. Emergency service is available so you are never left in the cold. Contact us today to schedule heating repairs in your Cincinnati home.

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