Warmflow Boiler Error Codes, Causes, Fixes & Troubleshooting

James Elston
Written by James Elston
Updated on 5th December 2023
Posted on 4th December 2023
Warmflow Boiler Error Codes, Causes, Fixes & Troubleshooting

Warmflow boilers error codes and faults – What they mean and how to fix them

warmflow boiler error codes & trouble shooting

From time to time, things are going to go wrong with your oil boiler. While it may seem like a nightmare to work out what’s gone wrong, error codes can give you an idea of what the issue is.

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Then, you’ll know whether it’s a quick fix that you can do yourself or whether you’ll need the help of an engineer or even worse, need a new boiler.

Even the best combi boiler will break down at some point and you will have to consider fixing or getting a new one.

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If you have boiler cover, then an engineer’s visit is quick and easy to arrange. If you don’t have cover, then we’d suggest getting in touch with Warmflow.

This will ensure that a suitably qualified professional comes to your aid. Also, some boiler cover policies can pay for you a replacement boiler.

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Common Warmflow Boiler Fault Codes and Problems

Some oil boiler problems are more common than others. To help you with your Warmflow boiler troubleshooting, we’re going to look at the ones you’re most likely to see on your boiler’s control panel and many of these issues can be prevented with an oil boiler service.

Warmflow boiler error code E01

Error code E01 means that no flame has been detected during the start-up process.  You should now see the reset button lit up in red. If you’re not sure where the reset button is, your boiler manual will provide guidance. Can’t find your manual? No problem, another copy can be downloaded at Warmflow here.

When the flame isn’t lighting, it can mean a lack of fuel getting to the burner. So, do make sure that your supply is okay before going any further. If there is fuel, then try resetting the boiler twice. If there is still no flame, then that’s when you will need to call out an engineer.


Warmflow Boiler Error Code E02

warmflow oil boiler

This Warmflow error code indicates that the safety thermostat has tripped. This happens when the temperature reaches 95°C.

Now, it might genuinely be a temperature issue, or it may also be a fault with the thermostat. Either way, it will need an engineer to carry out an inspection to establish what the problem is.

Warmflow Boiler Error Code E03

Error code E03 means that the flue thermofuse has tripped. The thermal fuse is designed to prevent your boiler from operating when there might be damage to the heat exchanger.  Again, it might be that there is a fault with the thermofuse rather than it indicating another problem.

An engineer will need to visit and carry out checks to see what’s causing the issue with your oil boiler..

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Warmflow boiler error code H20

The H20 code means that your boiler system has low pressure. Now, this is one that you’ll be able to fix yourself without needing additional help.

That’s because it can be resolved by simply topping it up with water. This is done by attaching the filling loop and then turning the valve to the open position.

As you fill the system, make sure that you keep an eye on the pressure gauge which you’ll find on the front of your boiler.

High pressure can cause as many problems as low pressure, so you want to avoid that situation. Once you’ve topped up the system, the pressure gauge should be showing 1 bar when the boiler is cold.  

warmflow boiler error codes & trouble shooting

Once you’ve finished topping up the system, make sure that the valve is fully closed, and then you can remove the flexible filling loop. It’s not usual for a small amount of water to come out of the pipe once the fillip loop is removed, but the flow should quickly stop.

For more information on everything to do with boiler pressure, take a look at our complete guide, which can be found here.

How Often Will I Need to Adjust the Pressure On my Warmflow Boiler?

If you’re wondering how often you will need to adjust the pressure, well, it is normal to see a drop in system pressure in the first week of operation. This then means that it’s important to check the pressure daily and refill as necessary. This is common with most types of boilers.

After the first week and assuming everything is running okay, make a note to check the pressure each month. The minimum pressure, which is shown by the black needle on the pressure gauge, should be 0.5 bar when the boiler is cold.

When the boiler is operating, then the pressure will go up to 2.5 bar. If you find that the pressure is too low or is outside of these figures, you will need a Gas Safe engineer to check the system.  

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All Warmflow Error Codes

Warmflow Boiler Error CodeProblem
E01No flame detected during the start-up process
E02The safety thermostat has been tripped at the 95°C point
E03The flue thermofuse has tripped
H20The system has low pressure
E05A fault with the heating sensor
E22A fault with the fan
E16Parameter programming request
E35A fault with the ionisation electrode
E42A fault with the fan printed circuit board (PCB)

Warmflow error codes and faults summary

When the boiler’s not working, a quick fix is needed. Error codes can then be really helpful in quickly working out what’s gone wrong and knowing whether an engineer’s visit will be required.

See our other budget boiler error codes sections for Biasi boiler problems, intergas boiler problems & Ferroli boiler issues.

You may find that your Warmflow boiler problems are just not financially viable to be fixed so getting a new boiler will probably be the best solution.

Here at Boiler central, we’ve made boiler replacement as easy and stress-free as possible with our fixed quote process.

Simply provide details on your hot water and heating needs, and we’ll provide recommendations and great boiler offers for the perfect fit boiler, all with a fixed price boiler quote.

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 4th December 2023

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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