I have the same problemn. Hope somebody posts a fix. I reckon it is something to do with air in the system reducing pressure at the boiler but I may be wrong there.
Roddy, September 2008
got the same problem with my Vaillant boiler, could anybody help?
Kevin, May 2008
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I can answer this question...
my shower runs hot then cold ect.its run from a combi boiler?