Vaillant 242e boiler?

Hi there can anyone help me with this problem on the turbomax vuw gb 242E boiler there is a heat temperture cut out sensor which has a small reset switch in th middle of the sensor, Well this keeps tripping on a daily basis i have checked the pressure on the gauge and this reads 1.5bar i have also blead and checked all radiators Which seem to be getting very hot as well as the hot water . When i first press the reset switch and call for hot water only the temperture gauge goes up to 90 degrees + i have tryed turning back the on board stat to 5 and this seems to have an effect for a while but the over temperture switch still keeps tripping out!! . Also i am having real trouble getting hold of an instuction manual if any one could help me with this i would be most gratefull as winter is comming and i have 2 small kids in the house many thanks Paul.