Heatrae sadia megaflow

[Morti]

Recently the megaflow cylinder has began to make a noise when not calling on stats for hot water and heating. On reaching temp the pump and boiler sometimes continue to run and fire with both Mv closed.Seems to come from the flow and return on the tank.I have changed the H W Valve.Any ideas?

 

[ianmcd]

Do you mean that you have changed the 2 port motorized valve on the feed to your unvented cylinder ?

 

[Morti]

Yes just changed the head as the spindle on the body is finger loose

 

[oldbuffer]

The motorised valve on an unvented cylinder is part of the three level safety regime. It can only legally be worked on by someone with the G3 qualification. If you don't have it, don't touch the cylinder or its controls and call in someone who has the necessary training and competence.