Hot Water Issue

[SIRandyraven]

Gas boiler - Tick works ok
Heating - Tick works ok
Hot Water - Issue

Run tap (any tap) and water after a while runs Hot ...very hot ...
then after 20 seconds goes mild warm.
Did this yesterday ...
Then later when I tried it again was ok
Same has happened today and now doing it as I type grrrrr.

Pump works ok and whirs ok ...and tested heating and rads got hot.
With Hot water only , it whirs ok ...but make a tinkling noise also.


Could it be the little metal box thing ....it has Auto and manual written on it ....

Either way have a call with BG for engineer to visit.

Also to top it all ...the main tank overflow is depositing water into back garden.
Spooky it has only started doing it this morning ???
Flushed loos (3 of them in house) and now not doing it anymore.

[tamborine]

Maybe an air lock - try key to release air

[The Builder]

Your little metal box sounds like it's the valve that diverts the hot water to either CH or HW. Simple replacement I guess.

The ballvalve in the roof tank may simply have got out of adjustment. Pressure rises overnight, and the float level may well have got too high. There shouldn't be any connection between that and the loos flushing.............. unless it's an older system where the loos used to be fed from the roof tank. In which case, drawing from the tank will have lowered the level.