what type of terminal should i have on the flue for a worcester heatslave 2?

Is it a Balanced flue ? if so it should have the manufacturers Flue terminal kit fitted

If it is a Conventional Chimney it should be lined and have a "Chinamans Hat" type Cowl to stop rainwater.

You don't say how old the boiler is but i'm guessing that it is not new, if it has worked OK for a year or so it probably needs a good Service by an OFTEC Engineer who will be able to clean and then set the burner to give clean & efficient combustion

www.oftec.org will assist in finding a r3egistered technician near to you

www.elanar.co.uk
May 2009