X400 is pretty mild and does not dissolve the debris.
I would use citric acid if the rads will take it.
Probably just use the boiler on DHW mode at first and then later through the rads if they will take it. Increasing concentration of acid as it becomes spent.
That has the benefit of dealing with the primary and secondary HEs together.
Tony Glazier
I would use citric acid if the rads will take it.
Probably just use the boiler on DHW mode at first and then later through the rads if they will take it. Increasing concentration of acid as it becomes spent.
That has the benefit of dealing with the primary and secondary HEs together.
Tony Glazier