5 Common Problems with Potterton Boilers and How to Fix them - CompariHome (2024)

Potterton is one of the best boiler manufacturers in the UK, but even their boilers can go wrong from time-to-time. In this guide, we will explain the five most common problems you are likely to encounter with a Potterton boiler and show you how to fix them. Some are DIY fixes you can do yourself, but others will require the help of a professional engineer.

If you have a problem with your Potterton boiler, you need to read this guide before you do anything else.

We will explain the five most common problems that most Potterton owners experience, what is the cause, and how the issues can be fixed. Some of the fixes are really simple and could save you a ton of money.

Lastly, we will also suggest the perfect place to look if your boiler repair is going to be too expensive and you might want to consider investing in a brand new one.

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The Five Most Common Problems with Potterton Boilers

#1 –Boiler Pressure Is Too Low

Low boiler pressure is a common problem with all boilers and Potterton boilers are as susceptible to this as any others.

If your boiler pressure drops too low, the boiler’s default failsafe mechanism will kick in and the boiler will lockout. When this happens, your boiler will stop working and you will have no central heating or hot water.

Low pressure in a boiler can be caused by a number of things including:

  • A leaking pressure release valve
  • A faulty boiler pump seal
  • A cracked heat exchanger
  • Leaking radiator valves
  • Minor holes or leaks in radiators and towel rails
  • Weak or failed soldering on piping joints.

How to Fix it:

It is usually recommended to fix an issue with low pressure in a boiler by topping up the system pressure. This is quite simple to do using the internal filling loop. But if the problem is being caused by a leak, it is only a matter of time before it reoccurs.

The only way to fix a leak is to find where it is and close it up. This is sometimes a minor job that you can do yourself by tightening a joint or using a DIY sealant. If the issue is with a soldered joint, it is usually a relatively minor issue to fix it.

Once you have identified and fixed the leak, you will then be able to repressurise the system and it should now work as normal.

If the problem is being caused by a more serious issue with an internal component in the boiler such as the heat exchanger, you will need to get an engineer to take a look and suggest the best course of action

#2 –Boiler Switches Off Before Radiators Are Up To Temperature

One issue which is a bit more unique to Potterton boilers is the boiler beginning to heat up the radiators but then cutting off before they have got up to full temperature.

With most boilers, this fault will generate either code E20 or E28 on your display panel.

The cause of this issue is usually the sensors inside the boiler that monitor the temperature of the water it is heating up.

If there is a problem with these sensors, they can begin to send messages telling the boiler the water is up to temperature when it isn’t. This causes the boiler to cut off and stop heating the water further.

Problems with these sensors are most commonly caused by one of two things:

  • NTC Thermistor – This is the proper name of the temperature sensors. Sometimes this component can go wrong but sometimes the problem can be with the printed circuit board (PCB) that isn’t receiving messages from this sensor properly.
  • Limescale – If there is a build-up of limescale on the NTC Thermistor, this can affect the sensors ability to measure temperature. If it measures the temperature incorrectly, this means it is likely your boiler will be unable to get hot water up to temperature.

How to Fix it:

This is a problem that you will need an engineer to help you fix. If the problem is being caused by limescale, the engineer will be able to clean things up using specialist chemicals. He will probably do this by carrying out a hot flush.

If the NTC thermistor itself is damaged, the engineer should be able to replace it. This component is not terribly expensive.

If, however, the issue is with the PCB, this is a more serious problem. PCBs are expensive to replace and you could be looking at a bill of £500 or more.

If you have an older boiler, you might, therefore, want to consider replacing the whole boiler with an energy-efficient new boiler that could end up saving you money in the long run.

#3 –Cold Return Pipe

This is an issue that can occur with all boilers and Potterton’s are no exception. When you switch on your central heating, it will push hot water around your central heating system and eventually, that water will return slightly cooler to the return pipe.

But if the water in the return pipe continues to be cold, this suggests that there is a problem with the water circulating in your system.

This can be caused by one of two things:

  • An issue with the central heating pump – the pump is struggling to push water around the system. This could be caused by a problem with the settings or even a blown seal.
  • Blockage – A blockage somewhere in your central heating is preventing water from circulating properly. This is usually caused by a sludge build-up.

On your Potterton boiler, this is most likely to be indicated by error code E125 or E193 showing up on your display.

So, there will be a differential in temperature, but not a huge one. A boiler will display a fault code such as the E125 and E193 and then lockout.

How to Fix it:

Regardless of which of the causes is the issue, you will need to get a qualified gas engineer out to look at your boiler.

An engineer will be able to examine the pump and check if any of the seals have deteriorated or split. If they have, they should be replaceable although if there are any other issues with the pump, it may need replacing which is an altogether bigger and more expensive job.

If the cause of the problem is a blockage, your engineer will be able to flush your system to clean out the debris that is causing the problem. If your heating system or boiler is older, try to avoid a pressure flush as these can cause more harm than good.

#4 –Fan Switching On And Off

The fan is a crucial component in any boiler as it helps to remove the harmful gases your boiler creates from your boiler. When you switch on your Potterton boiler, you might well notice a small whirring sound as it fires up.

This is the fan and your boiler needs to know that the fan is operating before it can switch other components on. If the fan isn’t recognised, the boiler will not start and if the signal is intermittent, the fan may end up switching itself off and on repeatedly.

There are a number of different things that can cause this problem including:

  • Wiring issues – if your boilers wiring has come loose or got damaged, this can affect the signal reached the printed circuit board (PCB).
  • Faulty Air Pressure Switch – If this switch is sending the wrong signals to the PCB, this can lead to this problem as well as others.
  • A damaged PCB – The problem could also be caused by an issue with the PCB itself.

There are also various different fault codes that your Potterton boiler could generate. These include E131, E133, E151, E152, E160 and E161.

How to Fix it:

This is another job for a qualified engineer as it involves testing components underneath your boiler’s casing.

An engineer will need to look at all of the possible causes of this problem to ascertain which issue your Potterton boiler has.

If it is a minor issue, such as the wiring, the fix should be relatively simple and affordable. If there is a problem with a major component such as the PCB, this is an altogether bigger and more expensive.

As we noted before, if you have an older boiler, you might reach the conclusion that your money is better spent on a brand new boiler rather than patching up an old one.

#5 –No Hot Water / No Central Heating

A relatively common issue with older Potterton boiler models such as the Potterton Promax, Suprima and Profile models is an issue where the heating works but there is no hot water.

A similar, but slightly less common problem is the other way round with hot water working but no central heating.

Both of these problems usually come down to an issue with the diverter valve. The diverter valve is the component in your combi boiler which directs hot water to either the taps and showers or towards your radiators.

If this valve gets blocked or stuck in any way, it can result in hot water making its way to one system but not the other.

How to Fix it:

This is another internal component issue, so you will again need the help of a qualified engineer.

They will be able to assess the diverter valve and if there is anything blocking it up or stopping it from moving, they will be able to clean it up. If it needs replacing, they should be able to do that too, although this is another fiddly job and could end up costing you a few hundred pounds.

Where to buy a new boiler

If your boiler is fairly old, our of warranty, and has a fault with a major component such as the PCB, it is usually wiser to replace the whole boiler rather than fix one component and then wait for the next one to fail.

If this is the decision you take, be sure to get a quote from Heatable. Heatable is an online installation firm that offers some of the best prices on a wide range of high-quality boilers from Potterton and all other major boiler manufacturers.

They have some great deals including extended warranties and are able to get your brand-new boiler installed fast and for less.


Potterton boilers are generally very good, but all boilers can develop issues, especially as they get older, and Potterton is no exception to this.

In this guide, we have outlined the five most common problems you are likely to encounter with your Potterton boiler. We have explained what the cause of the problem is likely to be and also what is needed to fix it.

Where the problem is a major one, you might end up deciding to buy a whole new boiler. If you do, we have recommended Heatable as the place to look for the best priced new boilers around.

Have you had problems with your Potterton boiler? Did our guide help you identify and fix the issue? Do you have questions about any issues we haven’t covered in this guide? Any tips for other readers that we haven’t mentioned?

It is always helpful to hear about readers views and experiences, so please do use the comment box below to share your thoughts with us today.

5 Common Problems with Potterton Boilers and How to Fix them - CompariHome (2024)
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