Flue outside property is discharging dirty water/sludge. Is this a blocked filter ? if so how much would it be to replace it and how long?

Bill, July 2012

Flues discharge water in the form of condensation-therefore this water should be clean.
Dirty condensation water is a symptom of incomplete combustion in the boiler producing soot.
Get the burner serviced by an accredited person who can take and analyse the the flue gas output.
An efficient burner is a clean burner

Geoff, August 2012

Boiler is a Vokera Linea 28

Bill, July 2012