Why would the heating come on even when the thermostate is down to zero and the control panel is set for water only? Also, when using the taps, the hot water goes cold, then hot, then cold etc all the time. Finally the boiler pressure climbs - nightmare. Any suggestions?

Bunny, June 2009

OK there are 3 reasons 1 the boiler fires dose the boiler have a pre heat hot water mode ? if yes then this right
2 the water gos hot then cold, you have a blocked heat exchanger or it scaled up clean of replace, 3 presser gos up it could be your filling loop is open or letting bye check or you need to put air in the expansion tank good luck

capitalboilers.co.uk, June 2009