Changing mid position valve - Basic advice please

[MettyMatty]

Hi,

I'm a newbie here and this is my first post so please be gentle.

I have a new Drayton MA1 mid position valve to replace the current one. The actual valve is broken off the spindle so everything gets hot (CH and HW simultaneously)

I was fairly confident about changing this over but had a quick look on the net to make sure I wasn't overlooking anything and now I'm not so sure...

I don't have an issue with draining the rads and it's straightforward as the draincock is on the lowest rad is by the back door.

What I'm concerned about and not experienced enough to get my head around is the hot water side of things. Baiscally I don't know what or where to drain it from or if I need to (will valves hold it)? I got confused about people using bungs instead of draining and comments about hot water cylinders collapsing started to really worry me.

I don't have a drain valve for the hot water cylinder, only isolation valves for either 'side' of the cylinder and either side of the pump. The mid position valve is about 1/3rd the way up next to the cylinder.

Sorry if this seems blinding obvious but it's only easy when you know how.

Thanks for reading.

 

[RickMoore]

You shouldn't need to drain the hot water cylinder to change a mid position valve.

 

[MettyMatty]

Thanks Rick!

I guess I just close the valve below the pump?

What about whats in the cylinder coil, how is this drained/isolated?

 

[RickMoore]

That should drain with the rest of the system if there is no isolation valve