Leak on fill valve

[JoeMill]

 

[JoeMill]

Water was randomly spurting from the rear of the valve (black plastic screw on) when I tightened this up it stopped. My question is what is the purpose of the black screw on cover and is there still likely to be an issue with the valve itself. Or was the solution really that simple!? Many thanks

 

[old duffer]

Water was randomly spurting from the rear of the valve (black plastic screw on) when I tightened this up it stopped. My question is what is the purpose of the black screw on cover and is there still likely to be an issue with the valve itself. Or was the solution really that simple!? Many thanks

valve has a flap/gate that rotates through 90 degrees to block the pipe diam. In order for the gate to be a water tight fit, the rotating gate is supported on a pin that locates through the main body hence protruding through

 

[JoeMill]

But what is the point of the black screw on? I'm wondering if there is a problem and me tightening it has just concealed it or is that the purpose of it?

 

[RandomGrinch]

But what is the point of the black screw on? I'm wondering if there is a problem and me tightening it has just concealed it or is that the purpose of it?

You have a filling loop with a double check valve.
The check valve stops C/H water potentially feeding back, contaminating the mains water supply.
The black screw can be removed to test the action of the check valve and to clean away debris from it, if necessary.
Tightening the end up should be fine.

 

[old duffer]

You have a filling loop with a double check valve.
The check valve stops C/H water potentially feeding back, contaminating the mains water supply.
The black screw can be removed to test the action of the check valve and to clean away debris from it, if necessary.
Tightening the end up should be fine.

is that akin to how electricity flows from a solar panel into the power station?