Can't isolate water to home(loft tank/hw cylinder)

[Sneezin]

Hi I have an issue, I have a system boiler downstairs with a hot water cylinder directly above it upstairs and then the hot water cylinder is connected to a cold water tank in the loft.

I have a stop cock tap in the front of my house under a flap, another stop cock under the kitchen tap.

I then have 2 red gate valve taps next to my hot water cylinder which look like this:

In case of a emergency leak in the house be it in bathroom or kitchen I wish to know how to turn off all the water in my house.

So I turned the 2 gate valve red taps off first (clockwise), turned both stop cock taps (outside and under kitchen sink) to off, ran all the cold/hot taps in the house for about 15-20 minutes till it ran dry.

Then went to check a slightly leaking hot water tap isolator valve under the kitchen sink and noticed its still coming out with plenty hot water, do I have to drain off the water in the hot water cylinder or loft tank or something else I done wrong?

 

[Elkato531]

The stop taps should stop all mains water entering the property but you will still have a significant amount of stored water. The gate valves are supposed to stop the water from leaving the cold water storage cistern (loft tank).
One of the gate valves will be on the cold feed to the base of the hot water cylinder. The other will be on the pipe feeding all your tank fed cold taps.
Unfortunately, gate valves are quite unreliable and after a few years they often don't close fully. Change them for lever valves if you want something more reliable.
If you need to work on tank fed taps, you can use bungs inside the cold water cistern to block off the relevant pipes.

 

[Sneezin]

The stop taps should stop all mains water entering the property but you will still have a significant amount of stored water. The gate valves are supposed to stop the water from leaving the cold water storage cistern (loft tank).
One of the gate valves will be on the cold feed to the base of the hot water cylinder. The other will be on the pipe feeding all your tank fed cold taps.
Unfortunately, gate valves are quite unreliable and after a few years they often don't close fully. Change them for lever valves if you want something more reliable.
If you need to work on tank fed taps, you can use bungs inside the cold water cistern to block off the relevant pipes.

thanks that does make better sense now, explains why I was unable to work on the hot water tap side in kitchen I will consider lever valves now.

This bunging of cold water cistern/loft tank, sounds like a bit of work perhaps having never done this, could a plumber fit an lever valve or isolator valve with tap handle to sort of do the same thing as bunging on the loft tank?

 

[terryplumb]

If you change the gate valves to lever valves you won't need any further valves near the loft tanks outlets ,but you can fit them if you wish.
A bung is basically a stopper ( like a cork in a bottle) that is put inside the loft tank to block it's outlets.

 

[Sneezin]

If you change the gate valves to lever valves you won't need any further valves near the loft tanks outlets ,but you can fit them if you wish.
A bung is basically a stopper ( like a cork in a bottle) that is put inside the loft tank to block it's outlets.

oh right yes It wouldn't be required with levers anyhow, is there any other way rather then doing this bung blocking in the loft tank since its very unsafe up there since no loft boards, one foot and ill probably go through the ceiling.

 

[terryplumb]

Turn off mains cold water stopcock ,and open all hot taps. That will drain the loft tank and any hot water stored in the cylinder. It will not drain the cylinder ,the cold water from loft tank will just displace any hot water leaving only cold water in the cylinder.
As this method wastes a lot of water it's frowned upon obviously.

 

[HERTS P&D]

Turn off mains cold water stopcock ,and open all hot taps. That will drain the loft tank and any hot water stored in the cylinder. It will not drain the cylinder ,the cold water from loft tank will just displace any hot water leaving only cold water in the cylinder.
As this method wastes a lot of water it's frowned upon obviously.

But is a lot safer for the diyer!

Andy

 

[Sneezin]

Turn off mains cold water stopcock ,and open all hot taps. That will drain the loft tank and any hot water stored in the cylinder. It will not drain the cylinder ,the cold water from loft tank will just displace any hot water leaving only cold water in the cylinder.
As this method wastes a lot of water it's frowned upon obviously.

thanks that sounds a safer plan!