Boiler advice please on cold water filling loop

[tally100]

Hi All,
I had a new sealed system fitted a couple of years ago and need to top up the cold water to the tank every couple of months and when i went to do it today i opened the levers on both on/off taps on the filling loop and found that the second on/off lever started leaking water quite badly so i need to replace the joint, it has a lever to turn it on/off and a screw to turn off the water completely, i can do the job by turning the earlier one to off but the question is do i have to drain the tank whats to stop the water in the tank running back out, advice will be appreciated

Thanks

Tally

 

[gassafeengineer]

is the leaking tap on the heating or cold main

 

[tally100]

is the leaking tap on the heating or cold main

Hi
It's leaking in the cold main into the bottom of the tank. it's coming out thr the lever which turns the water on/off

 

[gassafeengineer]

sealed system with a filling loop OK but i dont understand the tank bit? why have you got a tank on a sealed system ?

 

[tally100]

sealed system with a filling loop OK but i dont understand the tank bit? why have you got a tank on a sealed system ?

Sorry am i confused here, I have a boiler that heats up water in a tempest mains pressure cylinder , its the cold main feed to that thats leaking, we had a tank in the loft but not anymore.

Thanks