vaillant turbomax plus 828e no HW

[allenvb]

dear all,
I have been asked to look at a vaillant turbomax plus 828e, the CH is working fine, but the HW is a bit varied to say the least. When the HW is is opened, the fan starts and boiler fires up, the temp starts to rise to about 70oC then drops to about 25oC then starts all over again, the diverter has been replaced, the filter has been taken out and cleaned. I went through the diagnostic check, and with the hw open the diagnostic code shows 0 which means its off, from this I think I need to replace the dhw flow switch, whould people agree, or is there any other thoughts?

Thanks

v

 

[Agile]

Any significant work on a gas boiler should be done by a registered engineer.

You seem to be describing a blocked plate heat exchanger!

Tony

 

[allenvb]

I have my ccn1 and cen1 and am waiting for my Gas Safe reg to return

 

[ColJack]

as long as it's not messing with the gas connection or the combustion parts of it, why would he need a registered gas engineer? it's only water..