Thanks Tony, Indeed it is an 824.
I had already replaced the diverter valve but still had the same problem.
You think it should be ok to just let it run now?
Just thinking about performance or safety issues.
Thanks
Paul
Hi, I have an Vaillant ecoTec plus 624 boiler, 3 years old. I have today replaced the main PCB as the diverter valve was not switching- this looks like it has fixed the problem. The question I have is regarding the replacement procedure for this PCB. The instructions that shipped with the PCB...