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.

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.

Find the Complete Guide to Central Heating Pump Problems and How You Can Fix Them here.

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.

Alternatively, why not speak to our trained pump professionals on 0800 112 3134? Offering you free guidance and advice, our pump experts can find you the ideal replacement pump in seconds.

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

First, close down the central heating system by switching off the electricity supply. Do this at the fuse box and notify everyone in the home or building. Make sure the power cannot be accidentally reconnected when you are working on the pump.

Never undertake a pump replacement while the current is running.

Step 2: Locate the central heating pump

It’s seems like the obvious step, but if you’re struggling to find the central heating pump, check in an airing cupboard or under the stairs.

Step 3: Take a photo of the electrical wiring

Now take a photo on your phone of the wiring schematic so you’ll know how to connect the new pump. You could even wrap different colours of electrical tape around the live, neutral and earth wires for ease of reference and so you’re absolutely clear on what goes where.

Step 4: Shut off the service valves (isolating valves)

First, close the service valves, which you'll find on the body of the pump, either by hand or with your spanner. This will shut off the water supply to the pump body.

Please note: If no valves are present, you will need to completely drain your heating system. Do not loosen the union nuts until you have drained the system.

Step 5: Waterproof the area

Lay down towels and avoid any potential spillages by placing a bucket or large bowl under the pump.

Step 6: Loosen the union nut

Now locate the union nuts which hold the pump in place. Gently turn the nuts anticlockwise (remember: leftie loosie, rightie tighty), and then remove the failed pump.

Step 7: Replace the pump

Ease the new pump into position, ensuring it fits snugly. Don't be tempted to re-use washers, as they can contract over time. Make sure you fit new ones in the union nuts for a watertight seal. Tighten the nuts finger-tight before finishing the job with your adjustable spanner. Now you can check for leaks by turning on the service valves or refilling the system.

Step 8: Dry the pump

Next, you’ll need to make sure the unit is bone-dry before reconnecting the wiring according to the wiring diagram you made earlier.

Step 9: Testing your new pump

Now to get your new pump up and running. Switch the electricity back on and kick-start the heating system by turning up the thermostat.

When the central heating system is up and running, check for any leaks or significant discharge of water. If you can hear the pump making any weird or banging noises, you may want to call a plumber to make a quick check over your new installation.

Step 10: Bleed the pump and complete the installation

Finally, it's a good idea to bleed the system to make sure there's no trapped air. Your pump will have a bleed screw that you turn anticlockwise until you hear a hiss. You’ll probably need to bleed the radiators as well to ensure the whole system is balanced.

You can read our complete guide to bleeding a central heating pump here.

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. 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 bursty 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.

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.

Need more information on buying a central heating pump? Read our complete guide here.