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Heating Compliance

Why Are Boiler Fault Codes This Unhelpful?

Boiler fault codes might not sound particularly interesting but they play an important role in the maintenance of social homes and they can be better.

Jayne Elliott
Jayne Elliott

Nov 09, 2020

Boiler codes just aren’t helpful to anyone other than a heating engineer and that’s quite a problem. Before writing this piece, I decided to do a bit of research and find out how many boiler fault codes there are. Following the first link in my search offered a catalogue of 32 separate manufacturers code guides. Worse still - that’s just for gas boilers. This doesn’t even cover any of the other heating systems. You might be thinking - well each manufacturer will have different criteria for different codes - which seems logical. What about the codes themselves then? So off I go and click on one of the manufacturers. Now I’ve got to click a model of boiler - fine and finally I am presented with a list of 15 different codes. Most of the codes, I must admit, mean absolutely nothing to me. One of those codes is FU. Before you ask - no it’s not a shortened version of the word you are no doubt thinking. In this case, the code means a “Difference greater than 50c – check isolation valves are open”. So naturally, I have some questions. What is my isolation valve, where exactly do I find it and is this a job that requires a certified heating engineer?

This isn’t a one-off instance. There are far more unhelpful codes. I thought it best to make sure that my first search wasn’t a fluke so off I go back to the world’s least interesting catalogue. I choose a different manufacturer and model and the next code I find is D4 341. That’s not a hotel room number - it means “Primary flow temperature rising too fast”. That’s somehow even worse than the first one - and I’ve no idea what to do. What is the first thing I’m going to do now then? I’m going to contact my heating engineer.

a problem

Let me propose a different situation

It’s an innovative idea - but what if my heating system just displayed something that I as a resident could understand. It could be as simple as:

  1. You can fix this problem
  2. You are not able to fix this problem - please report the issue and book an engineer

This helps to ensure that If it’s something I can fix (and not make worse) that I’m not only saving the engineer time but also likely fixing the issue quickly. It would be useful to know that if I don’t try to fix it then will the problem get worse?

Here is an even bigger leap - what if the heating system took care of the whole process. This would improve the user experience for every type of customer. If the problem is something that the resident could address, then the heating system sends an email, SMS or even a notification to a device of your choice. That could be an Alexa or Google home or a smartphone app. If the problem doesn’t appear to be sorted within a specified date range then it could send them a reminder. Even better - it could automatically report the problem to the engineer or support contract responsible and give the resident a notification about when they will be coming.


This might be surprising - this is all technically possible.

Most heating system manufacturers subscribe to OpenTherm, a platform which facilitates the integration of heating systems with smart heating controls and other technology platforms. Others still have their own Web Service API-based method for integration. Some smart heating control companies can then ingest (they don’t so much eat as gather) information passed from the heating system. This can be used for a variety of things, such as optimising the temperature of the water to make heating the home more efficient. There is a secondary benefit, however, because with that data they can ingest the boiler fault codes. This means that their platforms can use Web Services (API’s) to talk to other communication tools, like Housing Repair Systems. This allows you to book an engineer’s appointment, and notify the resident through their preferred method - be it SMS, Alexa or even pigeon post.

We are already starting to see some of these technologies being blended together and sold as a single solution. Technology that, 3 years ago, was new and felt less than useful has now become a truly useful tool for helping housing providers. The Industrial Revolution 4.0 is happening here and now. What is deemed ‘smart’ today will soon be historically dumb and replaced by new capabilities with automated processing. You won’t even notice they’ve happened - routine tasks will never come to your attention like looking at your FU code.

Check out our guide on LGSR and Heating Maintenancelgsr-whitepaper-blog-teaser-min

Jayne Elliott

Jayne Elliott is a Business Manager at Switchee. Jayne has worked in the Social Housing arena for circa 30 years. She started as a Housing Assistant at a Local Authority and then moved into Housing Software, both product delivery and sales. Prior to Switchee, Jayne worked as an Account Manager at Orchard.

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