Electric System Boiler

I am currently in the process of building my own electric system boiler. This comprises of using electric shower parts such as the heater can as the boiler heat exchanger, a pump from an old boiler, flow, pressure and temperature sensors, 15mm pipe, a custom made ATMega powered PCB, LCD display, relays, water flow valves and a steel outer enclosure. I was inspired into this project after our house gas boiler stopped working one day, knowing nothing really much about boilers at the time I quickly learned how they worked, which in this case was fairly easy due to it being a system boiler and fairly modern one. I also learnt how they are wired including S and Y plans, and if I could build my own as an alternative say to a heat pump, and plus I wasn’t going to build my own gas boiler given how unsafe and explosive gas can be, and I’ve got no experience with working in appliances using it.

I then thought one day while the boiler was being repaired, I could build my own, initially I thought quite small ie kettle level as a way of heating the water. However I soon realised as you can imagine that this was nowhere enough power to heat a house and or a cylinder at the same time so more power was needed. It was at this point electric showers crossed my mind. I started looking online to see how these worked, which again turned out is even simpler than a conventional gas boiler. I looked on popular online shopping sites and could find heater can parts along with other boiler spares mainly for the boiler we had that broke. At this point I knew it was possible to start building one.

I got to work designing the boiler using MS paint. I designed the exterior and internals of the boiler, including the enclosure, as part of this process I spent a good while researching parts to make sure they were compatible, this mainly was plumbing components such as compression adapters, valves, piping etc. I also looked into electrical components such as how to switch the heater can elements on safely given the amount of power being drawn, a water temperature controller, the wiring, the main PCB that will be the brain of the boiler and control the LCD. For the PCB I initially looked into Raspberry Pi but soon found this wasn’t suitable for the project, so went with Arduino. I then set on writing code on my Arduino and testing this using LEDs and buttons to replicate some functions, which went well.

Aa part of the design process I needed an enclosure suitable to house all of components, before I found a suitable enclosure I checked dimensions and material used for the gas boiler we had. I then looked on electrical hardware supplier’s websites to find a suitable wall mountable steel enclosure, I found one that was a little bit short in height by 10cm but other than that was nearly the same dimensions as the gas boiler we have. Knowing the components inside were smaller and not needing as much space I knew this would ok despite the shorter height.

After playing around with design, I decided to take a look further at the Arduino side, and decided I fancy this being on one PCB and all integrated rather than sticking an Arduino inside. I set about a design for the PCB again in MS Paint, and then later built the schematic and PCB design online. As part of the PCB design and electrical stage, I decided that safety sensors were necessary to ensure safe operation, this included thermocouples, water pressure and flow, temperature, voltage and current sensors, these all had to be factored into the code and the design of the internals of the boiler and PCB including connections etc. I have also factored in a pressure relief valve, auto bypass, and auto air vent to ensure safe operation such pressure get to high or radiator TRV valves all being closed.

Currently at this stage the boiler has been fully designed, and the code at a stage where I need the actual physical parts to be able to test and code further. I will be in the next few months be constructing this boiler, and I will update this project as I move along in the project. I also aim to show you it in operation.