Isolating boiler to test if hex is causing pressure loss

[Matt0029]

If Isolating a boiler to determine if the leak is on the pipework or the boiler. If pressurising to 1.5bar then isolating the flow and return for an overnight test. Is it still acceptable to use the combi boiler for hot water? Expansion vessel located in the boiler.

 

[ShaunCorbs]

Yes fine to use hot water but it may invalidate your test if the expansion isn’t good enough eg over 3 bar etc