Ideal Boiler L1 Fault Code
The Ideal fault code L1 lack of water or overheat Q & A or require an engineer for an emergency boiler repair.
The Ideal Boiler Fault Code L1 Error Common Q & A
Just below, we have a list of common questions relating to the L1 fault code on the Ideal boiler.
- What does the L1 fault code mean on my Ideal boiler?
- What is the flow on my boiler?
- Is a boiler showing the L1 fault code dangerous to use?
- How do I reset my boiler to clear the L1 fault code?
- What could be the possible cause of the L1 fault code being displayed?
- What happens if the flow thermistor is faulty?
- Why would the thermistor be faulty on my boiler?
- How much does it cost to fix a broken flow thermistor on an Ideal boiler?
- What is limescale?
- What happens when limescale settles on the flow pipe on my boiler?
- Is there anything I can do to fix my limescale problem?
- How would my heating pump be causing the L1 fault code to be displayed?
- My pump was full of debris, how can I prevent this from happening again?
- What has the PCB got to do with the L1 fault code?
- How can my boiler engineer check to see if the PCB is at fault?
What does the L1 fault code mean on my Ideal boiler
According to Ideal, the L1 boiler fault code relates to a lack of water flow, or an overheat on the flow temperature.
What is the flow on my boiler
The flow pipe on your boiler is the one where hot water leaves after it’s been heated. This will be hotter than other pipes such as the return.
On the flow and return pipe, there are thermistors. These are sensors that take resistance readings based on the temperature of the water. This resistance reading is sent to the printed circuit board (PCB).
If the temperature reading is within the boiler’s operating range, it will continue to work. When the temperature is too low, or in this case, to high, the boiler will lock out and display a fault code.
Is a boiler showing the L1 fault code dangerous to use
Your Ideal boiler should show a boiler fault code and then lock out. The lock out means the boiler will cease to work, and this usually makes the boiler safe.
However, if your boiler displays any kind of fault code and doesn’t lock out, it’s wise to turn off the appliance and call a Gas Safe engineer.
The lock out is designed to protect the boiler’s components, in case continued operation would damage them. It’s also designed as a safety feature.
How do I reset my boiler to clear the L1 fault code
As we’ve mentioned, the lock out function is designed as a safety precaution. Therefore, you shouldn’t be resetting your boiler until the problem has been fixed.
Work on boilers should only be completed by a Gas Safe engineer.
What could be the possible cause of the L1 fault code being displayed
There are a few obvious things that your boiler engineer will need to check if the L1 fault code is being displayed.
The problem could stem from:
- Faulty flow thermistor
- Limescale build-up on the flow pipe
- Broken heating pump
- Malfunctioning PCB
What happens if the flow thermistor is faulty
If the flow thermistor on your Ideal boiler is faulty, the readings it’s passing on to your PCB could be incorrect. In this case, the temperature reading might be much higher than it actually is.
The boiler’s PCB recognises this as being unsafe and locks the boiler out, displaying the L1 fault code.
Why would the thermistor be faulty on my boiler
Typically, this is just an old-age issue. The vibrations from the boiler could have worked loose or damaged the connections to the thermistor, causing it to pass on intermittent readings to the PCB.
How much does it cost to fix a broken flow thermistor on an Ideal boiler
Luckily, this is one of the cheaper repairs on boilers. The thermistor itself will cost around £40-50. You should expect to then pay a Gas Safe engineer £80-100 to diagnose and fix the problem.
So, all in the cost of the fix will be in the region of £120-150 and is likely to take a boiler engineer a couple of hours.
What is limescale
Central heating systems hold their pressure thanks to the water that they contain. This water isn’t purified, as it comes straight from the mains supply.
Unfortunately, mains water contains lots of minerals (some areas more than others). These minerals can settle on parts in the central heating system.
On boilers, we find they settle most prominently on the heat exchanger, but also the flow pipe.
What happens when limescale settles on the flow pipe on my boiler
Where limescale settles, the water tends to burn a little hotter than it does in the rest of the heating system.
This isn’t necessarily dangerous, but it does pose a slight problem. The flow thermistor is trying to accurately monitor the temperature of the flow water. If limescale has settled near where the thermistor is monitoring temperature, it’s going to be receiving a temperature reading that’s higher than it should.
So, whilst the temperature reading at the thermistor might be too high due to limescale, the rest of the heating water might be at the perfect temperature.
The problem is the PCB only recognises the reading from the thermistor, not the overall water temperature – it will lock out and display the L1 fault code.
Is there anything I can do to fix my limescale problem
Manufacturers such as Fernox and Sentinel produce limescale remover. They’re sometimes labelled as “heating silencers”. This is fluid that you add you your heating system. As the chemical passes over limescale, it starts to break it up.
This can be caught in a limescale reducer (a small filter), but preferably the system will be flushed to remove all limescale, and a magnetic boiler filter will be fitted.
If this doesn’t fix the problem, the section of pipework causing the problem and the thermistor may need to be replaced.
How would my heating pump be causing the L1 fault code to be displayed
Your heating pump is what circulates water around the heating system. So, if there’s a water circulation fault, this component needs to be checked.
It can also be linked to an overheat. If the water isn’t being circulated quick enough (or at all), the water coming out of the boiler is going to be above the temperature that it should be.
The first thing a Gas Safe engineer will need to check is that the pump is on the right setting. Newer pumps such as the Grundfos UPS2 have 3 speed settings. If you live in a large property with lots of radiators, it’s likely you need to be on the fastest flow setting.
The engineer will also need to check that the pump isn’t blocked in any way. First, they’ll bleed the pump using the bleed screw. An air lock in the pump can hinder its circulation potential.
Whilst they have the boiler casing off, they’ll take the pump apart and make sure it’s free from debris. This debris comes from heating sludge that builds up in the heating system.
If the pump’s shaft and bearings are in good condition, the pump can be refitted to clear the L1 fault code on your Ideal boiler.
My pump was full of debris, how can I prevent this from happening again
It’s likely this debris has come from rust. That breaks off the inside of radiators, towel rails and copper pipe.
The quickest and easiest way to prevent this is to:
- Load the system with heating inhibitor and run a hot flush to get rid of existing heating sludge
- Top up the heating system and add more inhibitor
- Fit a magnetic boiler filter to catch debris
What has the PCB got to do with the L1 fault code
If the boiler engineer still can’t find the problem, there’s a good chance it’s related to the PCB.
The PCB is at the core of your boiler. If it doesn’t work correctly, neither will your boiler.
For instance, it needs to take readings from the thermistor. But if it’s not translating those readings correctly, it may lock out the boiler even when everything is operating as normal.
How can my boiler engineer check to see if the PCB is at fault
The first thing they can do is do a visual inspection. They’ll be looking for loose wiring and any burnt out connections. If they find any, these need to be rectified.
If nothing comes of a visual inspection, they’ll need to look at testing the unit with a multi-meter. This will determine whether the PCB is faulty.
If the PCB on your boiler is faulty, you’ll need a replacement. Generally, we’d expect a new PCB to cost in the region of £400-500 depending on the model of boiler that you have.
Other Ideal boiler issues
For more boiler issues regarding the Idea Boiler then please visit the Ideal Boiler Problems And Cures page.