The central heating pump is the beating heart of your central heating system, efficiently circulating hot water around your system to heat your radiators and keep your home warm.

But what happens if you have a problem and the central heating pump fails? If you're a competent DIYer, this is a job you can tackle yourself if you follow a few relatively simple steps. Otherwise, it’s time to call a plumber and a qualified electrician.

Today, you’re going to learn how to replace a central heating pump. Taking you step by step through the replacement process, your pump will be back in full working order in no time.

This guide will cover the following:

Why did my central heating pump fail?

Central heating pumps fail for a variety of reasons. The most common reasons for failure are corrosion to pump components and a failure to flush through the system on a regular basis.

If your pump isn’t circulating water around the system and the body of the pump feels quite hot, then you will probably need to fit a replacement.

If your existing pump has lasted for 30 years, then you may wish to replace it with an energy-efficient model.

If you would like to try fixing your central heating pump first, why not read our complete guide to central heating pump problems and how to fix them? Taking you through a variety of central heating pump problems, the guide can help you find a solution to your problem.

Finding your new central heating pump (before you start)

Before you start removing the old pump, it’s important you find the ideal replacement for your system. Start by noting down all the details and measurements of the old type of pump.

Specifically, start by measuring your old pump and make a note of the brand name, pump name and settings. It may be easier to take a photo for future reference.

If you’re replacing an older pump, check if it's a standard size. If not, you may need special adapters. Measure the pump valves.

Next, you can start searching for a replacement heating pump. If you have the name of your pump, try searching on our website. Our website will find the ideal replacement for your plumbing system based on your previous requirements.

Tools needed to replace a central heating pump

You’ll need to equip yourself with the following tools and equipment:

  • A new central heating pump
  • A plumber's tool (pipe wrench, adjustable spanner)
  • An electrician’s screwdriver
  • A bowl or an old paint tray and some towels
  • Paper and pen/your phone

How to replace a central heating pump (step by step)

Step 1: Shut off the electrical connection and water valve

step installing a central heating pump


Before you start removing the old pump, you will want to switch off the electric power source to the pump. You can do this at the fuse box. The next step is to shut off the main water valve. This is the main water valve supply to the house and should be turned off before any attempt of removing the pump. You can do this by simply turning the shut-off valve clockwise.

Important: Make sure you notify everyone in the home or building that you are working on the plumbing system.

Step 2 - Protect against water and electrical damage

step 2 installing a central heating pump

Your pump will either be located near the boiler or in an airing cupboard. Before you start working on the pump, make sure you take of a photo on your phone of the wiring schematic. You could even wrap different colours of electrical tape around the live, neutral and earth wires for ease of reference.

You can now disconnect the electrical wiring. Once you have completed the job, make sure you have completed this quick checklist:

  • Has the electricity been turned off and isolated? Check by using the electrical tester.
  • Have you turned off the main water supply at the shut-off valve? Double check before starting work.

If you are not confident about switching off the electrical connections or you are not knowledgeable about the power points, call a qualified electrician to do the job.

If all is fine, use the pliers to shut off the water to your pump at the gate valves (also known as isolating valves or pump valves). These will be located on either side of your pump. Simply turn clockwise until touch tight.

Step 3: Drain the pump

step 3 installing a central heating pump

The next step is to drain the pump. Start by removing the bleed screw in the centre of the pump. This should drain the system. Then, place a small bucket underneath the pump and start unscrewing the nuts connecting the pump to the pipework.

When one side is loose, check the state of the water flow by wiggling the pump end. Use the pump and allow the water to leak out.

Step 4: Remove the old pump

step 4 installing a central heating pump

Once the above tasks are complete, you will be able to unwind all of the nuts connecting the pump to the pipework and remove the pump from its location - making sure all the time that any old seals are also removed from valves.

When removing the pump, make sure you hold the pump over the bucket to catch any left of water trapped inside the pump

Step 5: Fit the new pump

step 5 installing a central heating pump

Now you can start to install the new pump in place of the old one. It’s important to ensure that the new pump’s seals are located correctly and connected tightly to the valves so there is no possibility of water leakage.

Step 6: Test for leaks

step 6 installing a central heating pump

Before turning on the main water supply, test for leaks by slowly turning one of the gate valves anti-clockwise. This should show up any leaks. If the pump starts to leak water, you will need to either tighten the nuts on either side of the pump or adjust the rubber O ring.

Examine all valves and connection points and tighten any valve or connections that show signs of leakage.

Step 7: Reconnect the main water supply and check for leaks

step seven installing a central heating pump

Reconnect the main water supply, open up the valves and re-fill the heating system. This should show up any leaks. Examine all valves and connection points and tighten any valve or connections that show signs of leakage.

Do not reattach any electrical connections before you are completely satisfied that the pump is not leaking.

Step 8: Reattach the electrical connections and switch on the main electricity supply

step 8 installing a central heating pump

If you are happy that there are zero leaks, reattach the electrical connections. Make sure that you are installing earth, live and neutral to the correct points – and if you are unsure on this aspect of the re-fit, contact a qualified electrician.

Once satisfied, switch on the main electricity supply to the pump, and if you have followed the steps correctly, the pump should be operating correctly without loud noises or rattling.

How to maintain your new central heating pump and system

A well cared for central heating pump will help keep your home cosy and warm for the next 30 years. But to keep the pump in good condition, it’s important to look after your whole central heating system. Otherwise you may have to buy a new central heating pump sooner than you think. Here are a few tips to help you maintain your new pump and central heating system.

Flush the system

It’s a good idea to flush your system through occasionally and to add a descaler and a rust inhibitor to it. Some descalers need neutralizing before an inhibitor is added, and you should always add the same inhibitor as is already in the system. Check the manufacturer’s instructions.

Install pipe lagging

As the winters get colder, the temperature drops can cause pipes to freeze. This can mean replacing burst or damaged pipes. To stop this happening, install pipe lagging. It only takes a few minutes to install and will give you years of protection.

Service the system annually

Make sure your central heating system is serviced by a qualified professional on a yearly basis to keep it running efficiently. Replacing a central heating pump can cost you thousands, a service will cost you pennies in comparison.

Check your radiators

Remember to check your radiators for trapped air. This often happens during the summer when radiators go unused for long periods.

Central heating pump installation costs

Central heating pumps are very technical, and they have to be installed by professionals, this is because it can be a very expensive job to fix if you choose to install it yourself.

So how much should central heating installation cost?

This depends on a variety of factors, some of the factors are:

  • How many hours it takes to install a central heating system
  • The hourly rate per region (on average)
  • Age of the house
  • If it’s the buildings first central heating pump (or its a replacement)
  • If there is no isolation valves
  • If it’s an emergency call out

All these factors will affect the price of the installation. 

We did our own research and came to these conclusions:

If you live in London or the South East

You’re looking at higher installation costs than the rest of the UK, with an average quote of around £350. That’s because the average hourly rate is much higher than in other areas of the country. 

If you live in the North East or North West

You’re looking at cheaper installation costs, with quotes of the cost to install a heat pump averaging between £150 to £180.

On average across the UK

The cost to install a central heating system is somewhere between £164 and £334 depending on where you live in the UK.

Every home is different

There is no standard price for central heating pump installation, there will always be a range of factors that may increase the price or the time a plumber needs to spend on the installation.

By following these guidelines, homeowners can not only address central heating pump issues effectively but also contribute to the long-term functionality of their heating systems. Whether opting for a DIY approach or seeking professional assistance, the key takeaway is the significance of proactive maintenance in ensuring a warm and comfortable home for years to come.

Ask the Professionals

If you do run into problems with your central heating pump, Anchor Pumps have a comprehensive range of replacement pumps, including highly rated energy-efficient Grundfos pumps.

Contact us for more details 0800 112 3134.