Boiler electrode replacement

I wanted to take a shower, but unfortunately the water didn’t warm up after a few seconds, or even a minute. When I inspected my boiler, it showed me error E4. In this scenario, you press “Reset”, knowing it won’t make a difference, but you still have hope. My hope was all gone after playing with it for almost 30 minutes.

I’ve been in a similar scenario before — and the technician that eventually came to inspect it told me a trick about cleaning the electrodes, to make it work again for a very short while. All openings of the combustion chamber are closed with a gasket. Removing the electrode to clean the contacts will badly damage the gasket, so you need to replace it very shortly after doing this, but it will still allow you to shower. So I took my screwdriver, removed the electrode and used the back of a sponge to clean the erosion from the contacts.

This unfortunately did not help. In the end I used my stove to heat some water. The next day I bought a new electrode and gasket (these sadly only come in packs of 10?). I figured that it was worth a sacrifice of 100 euros. I would learn something regardless and at worst it wouldn’t work — which it didn’t anyways. The boiler is 15 years old, so it is probably due for a replacement in a few years anyways.

Opening up the boiler is very straight forward, and I just followed the picture/instruction inside of the unit. The collection of photos below shows the action

As a warning, boilers like this can be quite dangerous! They can leak gas, or even produce toxic carbon mono-oxide. That is why I have installed a detector for both, and I will only keep the boiler running while I am present and awake for the next few days.

The new electrode was much cleaner than the old one, and after installing it, everything worked flawlessly. It achieved ignition at the first attempt.