Draining combi boiler system?

[ben100]

I am currently draining down & refilling my combi boiler system after adding sentinel x400. I've done it about 5 times now & the water is not dirty but just a sort of yellow colour. How many times do I have to keep doing this as it is taking quite a while draining down each time?

 

[oldbuffer]

Think you've done enough. X400 won't cause any damage anyway. Final drain down and add X100.

 

[kidgreen61]

Run cold water from the filling loop into the system, turning every rad off one at a time to force water through it whilst keeping the drain cock open?

 

[ianmcd]

X400 wont do any damage if some left in

 

[ben100]

Think you've done enough. X400 won't cause any damage anyway. Final drain down and add X100.

I think I've got all the X400 out it's more the fact of how clear I have to get it as some say it's ok with the little colour to it others that it needs to be completely clear water draining out?

 

[muggles]

You'll never get it completely clear