19/05/2026
Call out for no hot water… Boiler fires but water is cold.
This was on a .uk ecoTEC+ 831 (2011)
The boiler S codes said it was in hot water mode but the water was cold and the heating flow pipe was getting red hot.
I done a few voltage and resistance checks, but ultimately the plastic on the diverter valve motor had broken which meant that it wasn’t moving in and out, it was spinning instead and staying in the heating position…
Experience tells us how to fix many things but it’s always good to do the electrical tests too to make sure they won’t be any call backs and helps build more knowledge, which is never a bad thing.
In this post you can see I used the test cards from to help hold and identify the X2 block, very handy, he also makes these for other boilers too, him him up in the comments below if you want to know more.
I’ve also used a reference document from V2 folder which is always handy to have, he has lots of useful information in the 4 folders.
And obviously the boiler MIs hold a lot of info, and it’s always worth booking onto a manufacturers training course if you want to learn more about breakdowns/testing/repairs etc.
Anyway, I always keep spare *WORKING* motors when I change a leaking diverter valve so I have a few 😅 and yep, you guessed it, Van Stock!
So I got this boiler back up and running on a single visit, and I even gave it a service after the repair. Happy days.
