Gate valve on 2ndary drain

[David Abbott]

Why would I need a gate valve on my secondary drain????

 

[SPR1968]

You don’t normally unless you wanted to seal it for some reason, maybe maintenance for example

 

[David Abbott]

Thanks mate

 

[gtguy256]

If you have a overflow box with three pipes a valve on the secondary drain sets the water level in the overflow box

 

[David Abbott]

I was told by the overflow manufacture that the water height in the external overflow box is controlled by the height of the secondary drain itself!?!?

 

[KStatefan]

You do not need a valve on the secondary. Adjust the full siphon drain valve to get a small amount of flow down the secondary.

 

[David Abbott]

And I would do that by raising the height or lowering the height of the secondary right???

 

[KStatefan]

And I would do that by raising the height or lowering the height of the secondary right???

You do not have the change the secondary pipe height. Just adjust the valve on the full siphon.

 

[David Abbott]

You do not need a valve on the secondary. Adjust the full siphon drain valve to get a small amount of flow down the secondary.

You do not have the change the secondary pipe height. Just adjust the valve on the full siphon.

So how would I know when the adjustment is good?? what sign should I look for

 

[KStatefan]

So how would I know when the adjustment is good?? what sign should I look for

Water is just trickling down the secondary