Drain it using several hand grenades obviously from a distance and refill it with unleaded after the dust has settled and light it up using yet another hand grenade.
should also eliminate any sludge problems
iain
November 2008
Just to add, its a combi boiler, the F30
Nazir Letap
November 2008
I can answer this question...
How to drain a Saunier DUVAL boiler and CH system?