I also had problems with the heating turning itself on and off. The boiler was still under warranty so called out the installer, he was baffled so he called out the Halstead rep. The Halstead rep found that the electrical voltage coming into the house was too high and told me to inform the local electricity board. They came and tested the supply and agreed so they turned it down at the sub station and it's been fine ever since(much to my amazement).
colin, September 2009