Hot water tank only getting to 46deg even with boiler on constant at 75deg??

[Johntheo5]

Can you check the motorized valve on the cylinder coil when the cylinder temperature next reaches 49C, there is a lever on the side or end of the actuator on this valve, if the valve has closed then you will feel a immediate fairly stiff resistance when you pull on the lever, if the valve is still open then there will no resistance when you start pulling on the lever.

Are you sure that the HW heating isn't being programmed on/off and that the boiler is then continuing to fire on (central) heating demand only?.

 

[-FRED-]

Will check the valve when I get home. Can confirm though that the hot water is programmed to be on 24/7, has been that way for years. If it's ever on a program it just goes cold before you know it.

 

[gas112]

as above check the motorised valve is still energised