Drain hot water tank - where to shut off

[DrEMa]

Hi folks, I need to replace one of the inline hot water booster pumps, so need to drain the heater tank before I can swap them out. I'm not sure how to shut off the supply to the tank/hot water system. I've enclosed photos of the pump, tank and valves around the tank itself. Can it be done at this point, or does it have to be the storage tank outlet in the loft? (I have a feeling I know the answer). Apologies if this is a stupid question, would rather get ridicule than a flood though

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Edited by DrEMa on Tuesday 22 October 16:35

[DrEMa]

See if I can get the other pics this time:

[miroku1]

What does this thing actually do ? Why you need it ?
Just turn the cold water supply off to header tank and drain , if however the heater thing is below the dhw draw off level from the cylinder then you’ll have to drain the cylinder to beneath this level , unless you fast !!

[DrEMa]

The little inline booster pump (the pic in my initial post) increases pressure to the hot water pipes in the house - mainly needed for the shower, otherwise we just get a dribble.

It sits near the top left of the heater tank (1st pic of my second post). I just wanted to know if either of the stop cocks in the other 2 pics are the ones I'd need to use to stop flow to the tank so I can drain it enough to replace the inline pump or if I need to find one in the loft.

Edited to add: I appreciate you responding and for reference, the main storage tank is pretty much directly above the heater tank in the pic.

[B'stard Child]

How big is the storage tank in the loft?

I hate wasting water (On a meter so pay for water and the sewerage charges as a % of water used)

If it was mine I'd isolate the feed to the cold water tank and use water normally to run it down (for us that's two days before we get down to a level just above the feed to the house and HW tank)

Bucket out the last bit so I can put it back

I'd then drain the level down to below that in line booster and remove and replace.

I've never seen an inline set up like that - I've always fitted salamander pumps at point of use (showers)

Have you got one on both hot and cold?

[g7jtk]

Turn the water off to the house and run it off, stick a carrot on the outlet fitting in the header tank are two ways if the cold feed valve doesn’t work. The red handled valves in the pictures look to be to do with the heating system rather than the hot water system.

[.:ian:.]

The cold feed to that tank is on the back side, none of the stop cockstops shown are connected to that.

There must be another tap? Right?

If you can stop the cold feed, this will stop the hot water being pushed out the top of the tank.

You will need to drain the residual hot water out of the pipes using the hot taps in the house.

The then water in the pipes will be be below that point, probably...

[DrEMa]

.:ian:. said:

The cold feed to that tank is on the back side, none of the stop cockstops shown are connected to that.

There must be another tap? Right?

If you can stop the cold feed, this will stop the hot water being pushed out the top of the tank.

You will need to drain the residual hot water out of the pipes using the hot taps in the house.

The then water in the pipes will be be below that point, probably...

thanks chap, I'll have a look and give that a go, might get a bucket and hose handy

Appreciate the other responses guys. It is an odd setup. Was done in place of an electric shower to keep the setup simpler as the shower had always been gravity fed.