Vokera Maxin 24e combi boiler - no hot water

[waveneygnome]

My sister has just moved into a house with a Vokera Maxin 24e combi boiler. The CH seems to work fine - boiler ignites and rads warm up.

But when she turns on any of the hot taps, the boiler doesn't fire up.
I have tried turning the switch on the boiler to hot water only, and the same problem occurs.

Can anyone suggest what I should check/try to help her?

 

[picasso]

Could be the DHW diaphragm has gone, does the boiler do anything when you turn a tap on? any noises or lights ?

 

[waveneygnome]

Thanks for your help.

Just spoke to my sister and asked her to do as you suggested, but:

No noise from boiler
No lights came on

What does this point to?

 

[picasso]

I would think its the diaphragm that has gone.

 

[biscuit77]

Before you replace the diaphragm, check the 2 small impulse pipes going to the dhw manifold, these are prone to blocking.