We have a (just out of warranty) Tubomax 828e combi (LCD display) and the (electric) diverter valve is acting up. Sometimes it doesn't switch between DHW and CH, even though the diagnostics say it has. What seems to happen is that the boiler attempts to move the valve, but doesn't move it far enough. If it was seized or stiff I'd simply change it out, but if the boiler is turned off, then back on, which exercises the valve, then the valve works quite happily for the rest of the day.
Now, the valve is in stock, which suggests it is unreliable, but I also notice that the board has been updated - anyone know what was changed?
I'm probably just going to swap the valve out, but I don't want to do that and find out it was the board. Neither are cheap... :(
Lee