Halstead Gold - isolating water from within the boiler

[vickybirch]

We have a Halstead Gold and have a plumber at home now wanting to fit a new heat exchanger (due to a problem with water temperature fluctuating).

This engineers doesn't know how to isolate the water supply from within the boiler. Apparently turning off the house's water mains isn't enough.

Can anyone urgently help?

thanks

 

[plumbnuts]

My strongest advice is to get the plumber out of your house ASAP and get somebody that knows what they are doing