Refilling the air gap on a megaflo.. please help!

[Jim8]

So I’m trying to refill the air gap as per the inscructions on the tank but I’m struggling to locate the mains cold water supply valve/knob. Can someone please explain this to me like I’m a complete idiot lol. Our megaflo is on the first floor of the house.

Which of these in the picture do I turn to shut off the cold water supply?

 

[cdbe]

 

[cross thread]

Looks like a blue tap on the left

 

[oldbuffer]

1. It the valve with the black handle highlighted with a red arrow in cdbe's response.
2. They are often very stiff to turn. If this is the case you can always turn the water off at the main stop-cock. If doing so, switch the boiler off as well.

 

[Jim8]

Thanks for the replies guys. So I figured it was that valve on the left but I just wanted to make sure

So with that valve shut off, is there supposed to be cold water coming out of the taps still? Because there is

 

[dilalio]

So with that valve shut off, is there supposed to be cold water coming out of the taps still? Because there is

Your cold isn't balanced with the hot, ie: both hot and cold after the prv.

So your cold is teed off before the shut off valve and won't stop when closing it.

You only need to isolate and draw off the hot to regenerate the air gap/bubble.

That discharge pipework isn't right either.