Cylinder coil

[Bahco]

Can anyone clarify that when a split cylinder coil (Y plan heating) is leaking into the DHW would it not be the f&e tank that would keep refilling.

I pointed out on another forum that the best way to prove the coil had gone would be to tie up ball valve in f&e and if the water level dropped this would prove that the ch water was leaking into the DHW.
Other poster said it would show up in the cistern feeding the cylinder.
I realise that the extra water would travel back up the feed pipe from cylinder but surely both ways would prove split coil

 

[htgeng]

It depends on the relative height of the two header tanks.

Case 1: The f/e is lower than the DHW tank.
Result: Water leaks INTO coil from cylinder and is pushed up into f/e. water will spill out the f/e overflow. Radiators will corrode.

Case 2: The f/e is higher than the DHW tank.
Result: Water leaks FROM coil into cylinder and is pushed up into DHW. water will spill out the DHW overflow. Mrs Jones will get black water out of her hot tap - or a lovely fishy smell if you are using DS-40

Both situations should be affected by pump running although I can't be @rsed to work out what will happen.

Perhaps a good homework question for NVQ-ers!

 

[Bahco]

Perhaps a good homework question for NVQ-ers!

I'll take it to college with me on Thursday then