Whats this valve for??


Postby plotnine » Sun Sep 14, 2008 1:14 pm

I have a simple fully pumped CH and HW system. The flow from the pump connects to the two zone valves from a tee connection. The controller allows for separate function of the zone valves so it is possible to have just hot water, just central heating, or both depending on timer settings.

I also have one gate valve which I can’t not see the reason for.

After the pump and before the tee to the zone valve there is a tee. This feeds to a gate valve that is just cracked open, the outlet connects to the downstream side of the HW water zone valve via another tee.

This valve is allowing the hot water to bypass the HW zone valve even when only CH is called for.

Any ideas why the corgie plumber who installed the system would have fitted it? Is it really necessary and how can I regulate the setting to prevent hot water heating when I don’t want it.
plotnine
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Sun Sep 14, 2008 1:06 pm

Sponsor

Simply Build It

Postby plumbbob » Sun Sep 14, 2008 8:31 pm

The valve is called a bypass, and ensures a continual flow of water around the boiler circuit if both motorised valves are shut. This is fitted to protect the pump and boiler. As you say, this valve should be just open enough to ensure a flow, any further, and the hot water would not be pumped around the heating circuit.
plumbbob
Rank: Project Manager
Posts: 1873
Joined: Wed May 07, 2008 9:59 pm

Postby plotnine » Sun Sep 14, 2008 9:39 pm

Thanks plumbbob.

Do you agree that this valve should be connected into the circuit after the pump and return liv e from the cylinder and hot watertank, not as it is currently jusat bypassing the hotwater zone valve?

plotnine
plotnine
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Sun Sep 14, 2008 1:06 pm

Postby plumbbob » Mon Sep 15, 2008 4:01 pm

Yes, I would normally expect the bypass to do exactly that; bypass the heating circuits not just the valves, otherwise the water will as you say, be heated even when the m/v is closed.

It may be worthwhile you just checking the plumbing again, taking particular note of the pump direction. It just seems strange someone should go to the trouble of fitting a bypass, and then go and fit it in the wrong place.

Are you sure the gate valve is not in series with the dhw circuit? This would be expected if a restrictor valve was fitted. Such a valve would only be partially open and is fitted to limit the flow through the cylinder coil forcing the remaining hot water around the heating circuit (if called for).
plumbbob
Rank: Project Manager
Posts: 1873
Joined: Wed May 07, 2008 9:59 pm

Postby plotnine » Tue Sep 16, 2008 3:23 pm

Hello Bob,

The pump flow definatey goes TO the tee which feeds the HW and CH zone valves. The gate valve is definately in parallel not series with the HW zone valve................I guess the plumber got it wrong.

I am happy that i have interpreted the circuit correctly, I was in Hydraulics all my working life so am used to sorting out other peoples systems.

Anyway thanks , you do seem to agree with me that its in the wrong place, I am past playing with spanners myself so i will find a reliable plumber, who speaks English, and get him to correct it for me. Thanks again

David
plotnine
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Sun Sep 14, 2008 1:06 pm

Display posts from previous
Sort by
Order by



  • DIY How to Project Guides

  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!



 


  • Related Topics