Potterton Boiler E125 Fault Code
The Potterton fault code E125 circulation fault Q & A or require an engineer for an emergency boiler repair.
The Potterton Boiler Fault Code E125 Error Common Q & A
Just below, we have a list of common questions relating to the E125 fault code on the Potterton boiler.
- My Potterton boiler is showing the E125 fault code, what does it mean?
- Why does my boiler lock out after displaying the E125 fault code?
- If I reset my boiler, it works for a few minutes then locks out again, why?
- What problems lead to the E125 fault code being displayed on my Potterton boiler?
- What could cause the bearings and shaft on the pump to become partially or fully seized?
- If the pump’s bearings or shaft have failed, what will the boiler engineer need to do?
- What is sludge and limescale build-up, and how would that affect the pump’s operation?
- What will my boiler engineer need to do to fix the limescale/sludge problem in my pump?
- How do airlocks get into the heating system, and can they be removed?
- After bleeding air from the pump, is that the system free of air locks?
- My engineer thinks there’s a major sludge build-up problem with my heating system, what can I do?
- How does the heat exchanger contribute to a circulation fault?
- Before refilling the heating system, are there any preventative measures that can be put into place to combat heating sludge?
My Potterton boiler is showing the E125 fault code, what does it mean
If your Potterton boiler is showing the E125 fault code on the display panel, it means there’s a circulation fault with your appliance.
All modern boilers have a range of fault codes that are displayed when certain faults occur. Using sensors and after receiving signals, the boiler’s printed circuit board (PCB) recognises when parts of the boiler aren’t working correctly. In this case, the circulation of water isn’t sufficient.
Why does my boiler lock out after displaying the E125 fault code
Each Potterton boiler has a lock out function, as well as a fault code system. If the boiler was likely to cause damage to components, or be dangerous due to continued operation, it will lock out.
In this case, the boiler locks out as continued operation is likely to cause problems with the pump being overworked, or the heat exchanger plate overheating.
If I reset my boiler, it works for a few minutes then locks out again, why
You shouldn’t keep resetting your boiler if it’s displaying a fault code. After a reset, it’s typical that a boiler will operate for a few minutes. But, as soon as the boiler’s PCB recognises that the fault hasn’t been fixed, it will lock out again.
Every time you reset your boiler and it operates for a few minutes, it’s likely that damage is being caused to internal boiler components. Instead of constantly resetting your boiler, you should call a Gas Safe boiler engineer, and they’ll be able to fix the problem for you. Once the fault has been fixed, the boiler is ready to be reset, and that’s going to clear the fault code.
What problems lead to the E125 fault code being displayed on my Potterton boiler
The first thing your boiler engineer is going to check is the pump. It’s the pump that circulates water around the heating system. If this fails, or has a problem, that circulation is going to be inadequate, and cause a fault.
Your boiler engineer will need to check:
- The pump’s shaft and bearings are not seized
- There are no air locks
- For sludge and limescale build-up in the pump
After discounting the pump as being the issue, they’ll want to check:
- The isolation valves below the boiler are open
- There are no airlocks in the heating system
- Sludge and limescale hasn’t built-up anywhere, causing a blockage (including in the heat exchanger)
What could cause the bearings and shaft on the pump to become partially or fully seized
If the pump hasn’t been installed exactly horizontal, that’s going to mean that the shaft and bearings wear out prematurely. As they do, the bearings will start to grind on the shaft, and it won’t move freely. But over time, the shaft’s bearings and pump are slowly going to seize. When this happens, the pump won’t be able to produce the output that it should, and this is going to lead to a circulation fault.
If the pump’s bearings or shaft have failed, what will the boiler engineer need to do
To fix the E125 fault code in this instance, the engineer has two options:
- Replace the offender (bearings/shaft) using a service kit
- Replace the pump
If the rest of the pump (besides the shaft and bearings) is in good condition, they’ll be able to recondition the unit. But, if the pump is extremely old and is likely to fail again, it makes much more sense to invest in a new pump.
Typically, a new pump from a leading brand like Grundfos, including the cost of installation, is likely to cost around £250.
What is sludge and limescale build-up, and how would that affect the pump’s operation
One of the biggest problems with all aspects of central heating, is limescale and sludge build-up. Limescale is mineral content in water, whereas sludge is iron oxide (rust) that breaks off the inside of radiators, towel rails and pipework.
As this travels around the central heating system, it settles and creates blockages. In this case, it could easily be the cause of the blockage, circulation fault, and the E125 fault code being displayed on your Potterton boiler.
What will my boiler engineer need to do to fix the limescale/sludge problem in my pump
If there’s no damage caused to the pump, limescale and sludge can simply be removed. But, if the stress of the pump being overworked means the motor is burning out, it might be that a replacement is a wise option.
How do airlocks get into the heating system, and can they be removed
Airlocks can find their way into a heating system in several ways. Typically, they find their way in via leaks. However, each time a system is refilled, it needs to be bled. So, it might be that the heating system hasn’t been bled correctly after the last time it was filled up.
The pump is the focus here, as that’s the device that helps with water circulation in a central heating system.
There’s a bleed screw on most modern pumps, and your boiler engineer will be able to allow air to escape via this bleed screw. This can be done when they’re checking it for sludge build-up, and the condition of the pump’s bearings and shaft.
After bleeding air from the pump, is that the system free of air locks
Once the air has been released from the pump, it’s time to bleed it from radiators. There are specifically designed radiator bleed keys available, designed for this very job. Your boiler engineer will carefully go through every single towel rail and radiator, making sure that they bleed any air that’s left in the system.
Between the removing the airlocks in the pump and in radiators, the circulation will improve dramatically.
My engineer thinks there’s a major sludge build-up problem with my heating system, what can I do
All heating systems fall victim to heating sludge; some worse than others. This is something that can build-up over years. But, once it settles, it can be extremely hard to shift.
If you want to remove heating sludge from your system, the most efficient way is to hot flush the system using chemicals. The combination of chemicals and heat will break down most of this sludge. Your heating engineer will then be able to drain down the system to remove this dirty water, and then refill it.
How does the heat exchanger contribute to a circulation fault
Before water is circulated around your heating system, it needs to be heated. And, it gets heated, by passing through the heat exchanger. As this water can contain debris, it’s natural that some is going to eventually settle on the heat exchanger. As it does, it creates small blockages.
These small blockages limit the flow of water through the heat exchanger and in turn, this affects the boiler pump’s ability to circulate it. So, when checking for blockages, the heat exchanger needs to be checked, as well as the pump.
Before refilling the heating system, are there any preventative measures that can be put into place to combat heating sludge
All heating engineers dose the system with heating inhibitor chemicals before refilling the system. This helps to break down heating sludge long term and protect your boiler.
But, it’s important that you have a boiler filter fitted too. Boiler filters help to catch the debris that the inhibitor breaks down. If you don’t have a filter like this, the debris will circulate in the heating system, until the next time it’s drained down.
And, during that time, it could block up important boiler components like the pump and heat exchanger, causing another circulation fault.
So, our advice would be to add inhibitor, install a filter, and if you live in a hard water area, you should also fit a limescale filter. A boiler engineer will be able to clean out both filters with an annual boiler service, reducing the chance of sludge/limescale build-up causing a problem in the future.
Other Potterton boiler issues
For more boiler issues regarding the Potterton Boiler then please visit the Potterton Boiler Problems And Cures page.