Contents


What is a central heating pump?

How does a central heating pump work?

What are the main components of a central heating pump?

Where is my central heating pump located?

Does a central heating pump use electricity?

How much power does a central heating pump use?

How long does a central heating pump last?

How do I size a central heating pump?

The four most common central heating pump problems (and fixes)

Does my central heating pump need replacing?

Which central heating pump should I buy?

Contact Anchor Pumps for Free Central Heating Advice


Introduction

Central heating pumps are a small mechanical tool installed on your central heating system, which allows you to pump hot water around your home efficiently.

But if this is the first time you have ever heard of a central heating pump or you’re replacing a boiler pump for the first time, the vast number of central heating pumps offer can be a tad overwhelming.

No doubt you’re thinking:

“What is a central heating pump? How does a central heating pump work? How do I size a central heating pump for my home?”

That’s why we’ve developed this complete guide to central heating pumps. Taking you step by step through the world central heating pumps, you will be able to buy, fix or replace your central heating pump in no time.

What is a central heating pump?

A central heating pump is a small mechanical tool installed on your central heating system which is used to speed up the process of circulating hot water from your boiler to your radiators and back to the boiler. The pump is an efficient tool that ensures water is moved around your home before it cools.

The diagram below shows you the placement of a central heating pump in a central heating system.

diagram showing the placement of a central heating pump in a central heating system

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How does a central heating pump work?

The heart of your central heating system, central heating pumps work by taking water into the pump, pressurising the water with the impellers, before then pumping the water around your heating system at a higher speed. This helps ensure that hot water is efficiently pumped around home your home.

Central heating pumps explained:

Step 1: Water Intake 

The water enters the central heating pump shortly after being heated by the central heating system.

Step 2: Impellers 

Central heating pumps are a type of centrifugal pumps. This means that they use impellers (think aeroplane engines) to pressurise water.

Step 3: Water outlet

When the water goes through the impellers of the pump, the water is then pushed out of the pump at a higher speed than it entered.

If you would like a more detailed description of how central heating pumps work, please watch the video below.

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What are the main components of a central heating pump?

Central heating pumps are not complex tools. Most pumps will be made up of six simple components that you can see in the diagram below. Please keep in mind that some pumps will not have a pressure adjust dial.

Water Flow Inlet

This is the area in which the hot, central heating water enters the pump. The diameter of the water inlet will be one factor that dictates the maximum flow rate of your pump.

Water Flow Outlet

This is the area in which the pressurised hot water exits the pump and travels around your central heating system. Again, the diameter of the water outlet will be one factor that dictates the maximum flow rate of your pump.

Pump Pressure Adjust

The pressure adjust dial is an electronic component of a central heating pump that allows you to increase the pressure of the water in your central heating system. If you are finding that specific radiators are not getting the required heat, then simply increase the pressure using the adjust dial.

Pump Pressure Adjust

The pressure adjust dial is an electronic component of a central heating pump that allows you to increase the pressure of the water in your central heating system. If you are finding that specific radiators are not getting the required heat, then increase the pressure using the adjust dial.

Pump Bleed Screw

If you find that your pump is not working correctly, then one common reason is that air bubbles are trapped inside the pump. This stops the impellers working correctly and can cause an odd, random banging noise.

Following manufacturer instructions, the pump bleed screw helps you bleed this air out of the system.

Electrical Connections

This is where you can manage the pump's electrical configuration. Again, read the manufacturer instructions before use.

Electricity Supply Cable

This is where you connect the pump to mains electricity supply.

diagram showing the different components of a central heating pump

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Where is my central heating pump located?

Each home is different, and the location of your central heating pump will be determined by the location of the boiler or the expertise of the plumber who installed it

Most of the time your central heating pump will be located:

  • Near the boiler or hot water cylinder
  • Airing cupboard
  • Under the stairs

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Does a central heating pump use electricity?

One of the great things about central heating pumps is that they only use electricity when you switch on the central heating system.

This helps save you money and stops you wasting electricity.

Most central heating pump will run off your main electricity supply, but you can also purchase cheaper, battery-powered models although we wouldn’t advise it.

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How much power does a central heating pump use?

Most domestic central heating pumps run on about 240 volts, which is about the same amount of power needed to operate a kettle.

Saying that, your central heating pump is unlikely to be on full power. We think you’ll be using about half of that power for the modern, well insulated home.

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How long does a central heating pump last?

All central heating pumps sold here at Anchor Pumps come with a warranty.

These are usually longer than the manufacturer warranty and are based on our experience with each pump.

These are not how long we think the pumps will last, but a minimum time frame for when the pump will be in peak condition.

Most pumps will last for well over 10 years without any hiccups.

Our warranties for central heating pumps are as follows:

Grundos Central Heating Pumps - 5 years
Lowara Central Heating Pumps - 2 years
Anchor Pumps Central Heating Pumps - 2 years
Dab Central Heating Pumps - 3 years

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How do I size a central heating pump?

One of the most common questions we get here at Anchor Pump is: How do I choose the correct central heating pump size for my home.

A few times we’ve even had customers sending us pipe layout diagrams, boiler metrics and insulation ratings.

We say, enough.

Choosing a central heating pump for the average home is not that complicated.

Unless your home suffers from particularly poor insulation, follow these rules:

Grundfos 15/50  for 2 to 3 bedroom houses (smaller house)

Grundfos 15/60 for 3 to 5 bedroom house (larger house)

Choose the larger option if you suffer from particularly poor insulation.

If you have a much larger home (lucky you) then it does get a tad more complicated. In most cases, you will need a visual inspection of the pipe sizes, type of radiators, boiler size etc.

If you’re struggling for advice, ring our dedicated pump experts for free advice on: 0800 112 3134 or 0333 577 3134.

We’re open Monday to Friday 07:00 - 17:30 and Saturday 08:30 - 12:30.

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The four most common central heating pump problems (and fixes)

As with most things in your home, issues will no doubt crop up with your central heating pump. If you’re having problems with your central heating, the pump may be to blame if you’re experiencing any of the issues below.

As usual, we’ve listed our best advice for fixing the problem. If you are not confident in dealing with the issue then please contact a central heating technician to assess your system.

1. My Pump is Rattling or Producing a Humming Noise

A pump that has been installed incorrectly will have an impact on your central heating system. Not only can the rattling have long-term wear and tear consequences on your pump, but it can also stop your pump from working efficiently.

Fix: Check the pump fittings. If you find any loose screws or bolts then tighten them.

2. My Central Heating is Making Noises

Not to be confused with noises coming from your pump, alternatively, you could be hearing a general humming or knocking noises coming from your wider central heating system. This could be a sign that air has entered into your pump.

Fix: If you suspect air has entered the pump then follow the pump’s manual to bleed the system.

3. My Pump is Making NO noise

As with all machinery, you should expect a small amount of vibration and noise. If your pump is making no noise and the central heating is failing to distribute heat evenly around your home, then you may have a jammed Impeller.

Fix: You’ll need to open the pump and thoroughly clean it. Foreign bodies can sometimes enter the water supply that can affect the running of the pump.

4. My Pump is Not Starting

If the central heating system is not activating the pump or a fuse has gone then your pump will not start.

Fix: Call a qualified professional to check the wiring.

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Does my central heating pump need replacing?

In some circumstances, the fixes listed above may fail to resolve your problem. Internal corrosion is common in central heating pumps, and in this instance, you will need to replace your pump.

While we advise calling a qualified central heating technician before replacing any equipment yourself, there are some circumstances where you can be confident your pump needs replacing.

My Pump is Too Hot to Handle

Generally, a hardworking pump will a be a tad warm, but if your pump is getting too hot to touch, then it may be a sign of severe damage. In this case, you may need to check the warranty of your pump provider, but generally, you will need to replace the pump.

My Pump is Making a Grating or Knocking Noise

If your pump is making a grating or knocking noise, then this could be a sign of severe damage inside the pump. Again, check your warranty with the pump provider. Most will replace the pump if the original was faulty.

My Pump is Only Heating Some of the Radiators

If your radiators are working downstairs but not working upstairs, then this may be a sign that the pump is starting to fail. If your pump has a pressure dial, then you can try to turn up the pump pressure, but if this fails to work, then you may need to invest in a new, more powerful central heating pump.

My Pump is Leaking

If the pump is leaking, then it may need to be replaced. This is almost certainly as a result of corrosion which can’t be fixed. If a brown liquid is leaking from the start capacitor, or it looks burnt out, you can replace this part only.

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Which central heating pump should I buy?

If you are in the market for a central heating pump then have a look at our recommended options below. They have all been tested by our in-house engineers and are the highest quality pumps available on the market.

1. Grundfos UPS2 15-50/60

Regarded for its high quality, the Grundfos UPS2 15-50/60 is a universal replacement pump. Directly replacing the old UPS 15-50 and UPS 15-60, it is ideal for tight-fit installations and can be fitted without disturbing the pipework. There is an option of the UPS2 15-50/60 to be fitted as a pump head only, meaning that it can be fitted onto any existing UPS pump types. So, what other benefits does the Grundfos UPS2 15-50/60 offer?

The Grundfos UPS2 15-50/60 is highly energy efficient, offering three different settings. The settings refer to the speed in which hot water is circulated around the system and distributed to radiators and faucets. The best speed setting to use is the lowest speed at which the system works without any problems. The lower the setting, the more energy efficient the pump will be. This pump is designed for a 4m, 5m or 6m performance.

The plug-in control box can be mounted on the top, left or right of the pump offering versatility and accommodating a range of installation options.

Find the Grundfos UPS2 15-50/60 here.

2. DAB Evosta 40-70/130

As the DAB Evosta is powered by a permanent magnet synchronous motor, it can generate torque at zero speed which in turn, creates constant oscillation through water membranes. This increases efficiency, enabling hot water to be pumped at high speed to radiators and faucets as and when required. An ideal replacement for older three-speed circulators, the Evosta 40-70/130 covers 4.5m and 6m head models with a single pump.

A big benefit of this particular circulatory pump is the frequency converter, which is highly energy efficient. A fitted electronic device detects any changes of demand within the system and adapts to one of the six variable speed settings available.

Find the DAB Evosta 40-70/130 here. 

3. Lowara Ecocirc 25-4 (180)

Perfect for single family houses or apartment buildings, the Lowara Ecocira 25-4 (180) uses a variable-speed electronically communicated motor type. The motor is powered by a spherical rotor, which is shaftless, reducing the amount of noise as the motor turns.

A ceramic bearing ball is encapsulated within the impeller unit as part of new anti-blockage technology. The ceramic bearing separates water flow from the parts of the system that are magnetic, which reduces the amount of magnetite and sludge build-up.

The Lowara model is fitted with a built-in sensor that monitors temperature. By ensuring that the pump ceases to continue working when the temperature of the water reaches 125 degrees, it prevents itself from overheating.

Find the Lowara Ecocirc 25-4 (180) here. 

4. CPL CP50 (130)

The CPL CP60 (130) is a high-efficiency, glandless circulating pump, which is perfect for domestic households and is simple to connect. A glandless pump operates with no shaft or seal, meaning that there is nowhere for the water to leak.

Offering versatility, this pump type can be used for all heating and air conditioning applications with temperatures ranging from -10 degrees to +95 degrees.

The CPL CP50 (130) is easy to operate and comes with a three-stage speed control system, which applies variable differential pressure. The varying pressure dials can be selected to suit radiator and underfloor heating applications.

Ensure that your house gives you a warm welcome this winter and take a look at our selection of domestic circulating pumps. By choosing to install a domestic pump, you can save yourself money on your energy bill by ensuring that your heating system is operating at maximum efficiency.

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Contact Anchor Pumps


If you’re struggling for advice, call our dedicated pump experts for free advice on: 0800 112 3134 or 0333 577 3134.

We’re open Monday to Friday 07:00 - 17:30 and Saturday 08:30 - 12:30.

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