No Heat?  No Problem: Troubleshooting Your Circulator Pump

When the winter season comes, homeowners want to ensure that their heating systems are in top condition. One common issue that homeowners encounter is a circulator pump running but with no heat. The circulator pump plays an important role in circulating hot water throughout the heating system, so when it is not working properly, the system may not produce heat. In this article, we will explore the possible causes of a circulator pump running but with no heat and the steps to troubleshoot and fix the issue.

Causes of a circulator pump running but no heat

There are several potential causes for a circulator pump running but no heat, including:

  • Airlock in the system
  • A broken or malfunctioning pump
  • Issues with the thermostat
  • clogged or dirty filters

Airlocks in the system: One of the most common causes is an airlock in the system. When the air gets trapped in the pipes or radiators, it can prevent hot water from circulating and cause the circulator pump to run but not produce heat.

Broken or malfunctioning pump: Another possible cause is a broken or malfunctioning pump. A pump that is not working properly may not be able to circulate water effectively, even if it is running.

Issues with the thermostat: Issues with the thermostat can also cause the circulator pump to run but not generate heat. A malfunctioning thermostat may not signal the heating system to turn on when it is supposed to.

Clogged or dirty filters: Lastly, clogged or dirty filters can prevent hot water from circulating through the heating system, which can cause the circulator pump to run but not produce heat.

How to troubleshoot the issue of a circulator pump running but no heat

Finding the source of the issue is the first thing to do if your circulator pump is working but there is no heat.

  1. Check for airlocks: Start by bleeding the air out of your heating system. This will involve locating the bleed valve on your radiators or boiler and opening it to allow air to escape. If airlocks were the problem, this should resolve the issue.
  2. Inspect the circulator pump: If airlocks are not the issue, the next step is to check the circulator pump. Start by ensuring that the pump is receiving power and is turned on. Next, listen for any unusual noises, as these could indicate a malfunctioning pump. Check for any leaks or damage to the pump as well.
  3. Test the thermostat: If the circulator pump seems to be working properly, the issue may lie with the thermostat. Begin by ensuring that the thermostat is set to the correct temperature and that the batteries (if applicable) are working properly. You can also try adjusting the temperature to see if this triggers the system to produce heat.
  4. Check the filters: clogged or dirty filters can prevent water from flowing properly through the heating system. Check any filters in your system and replace them if they are dirty or clogged.
  5. Look for other issues: If none of the above steps solves the issue, there may be other problems with your heating system that are causing a circulator pump to run but no heat. Consider calling a professional to help identify and fix any more complex issues.

Tools and equipment needed for troubleshooting

While addressing the problem of a circulator pump running but no heat, the following tools and equipment may be useful:

Screwdrivers: You may require a set of screwdrivers to access and inspect various heating systems components, such as the circulator pump and thermostat.

Pliers: Pliers can be used for removing and replacing components of a heating system, such as filters or hoses.

Bleed key: If airlocks are suspected as the source of the problem, a bleed key may be required to remove the air from your heating system.

A multimeter is a tool for measuring electrical current, voltage, and resistance. It can be used to check the electrical connections to the circulator pump or thermostat.

Pipe wrench: Use a pipe wrench to tighten or loosen pipe fittings and connectors in your heating system.

A boiler pressure gauge can help you monitor the pressure levels in your system, which can affect the working of the circulator pump if you have a boiler-based heating system.

Replacement parts: Depending on what you discover during your troubleshooting, you may need to replace various heating systems components, such as the circulator pump, thermostat, or filters.

How to fix a running circulator pump without heat

There are numerous fixes for the issue of a circulator pump running but no heat if you have located the source of the issue. Bleeding the radiators and pipes should let any trapped air out and allow hot water to flow through the system if the issue is brought on by an airlock in the system. A specialist may need to fix or replace the pump if it is faulty or not performing properly. The thermostat may need to be replaced or recalibrated if the issue is with it. To guarantee appropriate water flow through the heating system, filters that are clogged or unclean should be cleaned or replaced.

Preventative advice for a circulator pump that is running but not producing heat

The key to avoiding expensive repairs and guaranteeing the longevity of the heating system is to prevent the circulator pump from running if there is no heat issue. Maintaining and testing the heating system regularly is one of the best strategies to avoid this problem. This entails inspecting the filters and, if necessary, cleaning or replacing them. Also, it’s crucial to check that the heating system is being used properly and to adhere to the manufacturer’s suggested maintenance schedule. Also, by regularly bleeding radiators and pipes to remove airlocks from the system, you can stop the circulator pump from running but not generating heat.

When Should I Call a Professional?

While some circulator pump issues can be fixed with basic troubleshooting, there are times when it is best to call a professional. Warning signs that indicate it may be time to call a professional include leak, strange noises, and a system that fails to respond to basic troubleshooting. Additionally, if you lack experience with heating systems or are unsure about performing the necessary repairs, it is best to hire a professional. When choosing a professional, be sure to look for someone qualified and experienced.


A common problem that homeowners may have throughout the winter is a circulator pump that is functioning but not producing heat. Airlocks in the system, damaged or malfunctioning pumps, problems with the thermostat, and clogged or unclean filters are just a few of the potential causes. Homeowners may make sure their heating system is operating smoothly and efficiently, providing warmth and comfort throughout the winter, by diagnosing and repairing the root of the issue and adopting preventative actions to maintain and inspect the heating system.

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