For the best hot water results turn you're Ideal iCOS boiler thermostat to max and always leave it set to maximum. Do not worry about the heating you can control this with you're wall room thermostat and timer. On the boilermate set the rocker switch for the central heating to timed, and the hot water rocker switch to constant and leave them at that. After about 20 mins you should now have a full store of piping hot water. If you are still not getting the results you want after setting the controls as described above then open the bath hot water tap at approximately 6 litres/minute. After about 2 � 3 seconds, check that the plate heat exchanger pump has kicked in. This is indicated on the A.C.B. by display segment H2.1. and the pump is the one on the middle right hand side, above the heat exchanger in the boilermate. if it is not showing on the A.C.B. display or you can not hear or feel it working then you check there is power to it if there is then you need a new domestic hot water pump. But these are the four wired pumps not the standard three so make sure you get like for like. If the pump is running then you need to check for correct opperation and if nesessary replace the Middle store sensor, the Bottom store sensor, the Domestic Hot Water OUT sensor, the Cold Water IN sensor and both of the Store overheat sensors. If they check out fine then test the mixer valve and finaly test the P.C.B and replace that if nessessary.