Can anyone help with a major problem I'm having? Bought a house last year. For 6 months heating and hot water worked perfectly. Then 1 day no hot water but heating still worked. Was told I needed a new diverter valve. Paid a gas engineer to come and fit this. After he did. Still no hot water. Was advised to get a new boiler. Bought a new boiler had it installed. Hot water worked for 1 day then again no hot water but heating still worked. Called out vokera who changed the heat exchanger. Hot water for 2 days and now no hot water again but heating still working fine. All in I've had 6 plumbers and gas engineers out over the past 6 months and none of them can work it out.