Describe Your Heating & Cooling Problem:
leaking pipe to heat exchanger on my valliant ecotec pro24 boiler only happens when boiler when heating is off for a few days then switched back on

steven, June 2009

There are 2 black pipes on the flow and return pipes to the heat exchanger these have a tendancy to leak where they connect to the copper. If your boiler is within guarantee period (2 years) get Vaillant to sort it.
If not drain boiler and either try tightening clips or replacing them.
But I'd recommend you get Vaillant to do it.

M, June 2009