Replacing Kitchen Mixer Tap

[whiskeyfrank]

I have to replace a mixer tap and the last time it was done someone did not fit isolator valves so i have to shut off the water and fit those too.

No problem for cold but how do i shut off the hot water supply. I have always had combi boilers but this one is a normal twin loft tank and hot water tank system.

I presume i need to drain the system, but how do i do that and how do i refill the system, also would this drain or affect the heating?

This type of CH & HW system is new to me so any help appreciated.

 

[JPC]

u might have agate valve u can close.

follow the pipe that goes from the bottom of the immersion up into the loft. does thsat one have a "tap". if so try and close it. if it closes thats it...open hot taps upstairs and downstairs and let the small amount of hot water left in the pipes run out.