Boiler acting strange during DHW

[Ifti]

Hi

we have a vaillant 242 combi boiler

the problem is that the boiler is acting weird as when we turn on the DHW, the boiler fires for a while, then cuts off and then fires again it keeps doing this as long as the DHW is on

any idea what we can tell the plumber to look at ? rather than him changing 5 parts we can tell him to start off by changing the one we suspect and take it from there

thanks in advance

 

[kidgreen61]

Our advice would be to engage a decent heating engineer, rather than a plumber.

It sounds as though your plate heat exchanger may be blocked.

 

[Agile]

The other thing is to pay him to diagnose the fault.

Never agree to pay for new parts which are not required to fix faults.

A good boiler engineer will be able to diagnose the faulty part and not just give you a list of new parts for YOU to buy for HIM to try!

Tony