What is this and what does it do?

[rotor]

Hi there,

I'm trying to gain an understanding of my plumbing at home, and there is one valve that I don't understand the purpose of. See the attached pictures. It connects the flow and return pipes (in the cupboard where the hot water cylinder is).

Could someone please tell me:

- Why flow and return need to be connected?
- What does this valve do? It has dozens of turns, and I'm a little afraid to keep opening it in case it falls off and water starts pouring out.
- What are the markings? H2O 6, 5, etc.
- Most importantly: what should it be set to? Wide open? Closed all the way?

Thanks very much in advance for your help!!

Untitled

• rotor
• 7 Apr 2015
• 1

Untitled

• rotor
• 7 Apr 2015
• 1

 

[Dan Robinson]

Its is a by pass valve to ensure a minimum flow through the boiler as the system closes down.

it protects the boiler and reduces system noise.

I'd probably leave it as pictured.

 

[rotor]

Thanks Dan. Exactly the info I needed, I've now learned a LOT more about why these are needed and how my whole system ties together. Thanks again!

 

[Dan Robinson]

No worries