Ravenheat condensing CSI Primary boiler has been cycling .I think the problem might be the controle thermostat.I checked the flow temperature at the boiler ,it seemed to be cutting out at 61deg (if the guage was right)I then removed the thermostat probe from its housing and the boiler worked fine ,temp went up to 85deg,no cycling,(it used to cut out at varaing times between5&90 seconds)I switched the boiler off before the overheat thermostat came into play.Ive been quoted £40 for the part at a plumbers merchants.I would appreciate any helpful comments on this problem.Thanks.