Preparing system after new pipe installation

[svouts]

I am thinking to clean a heating system which has some 40 years old steel pipes, cast iron radiators and some newly installed steel pipes.

I am thinking to use Sentinel X400 first to clean the system before using normal inhibitor.

Is there any risk that by cleaning the system will create leaks in the old pipes connections?

 

[dilalio]

Is there any risk that by cleaning the system will create leaks in the old pipes connections?

Always an element of risk I guess.
What is the pipe size? Steel barrel?
If you just do a mains flush, what's the colour of the water like? Is it full of rusty orange gunk? This indicates the inside of the system corroding and the sludge "could" be keeping any pinholes covered up and preventing leaks.