mystery valve

[dampsquib]

can anyone tell me what this valve is on my hot water tank - Just to clear up where it is, coming down through the pump bypass, through the first valve, into a T junction. one half dissapears off into the floorboards, the other goes through this mystery valve, back into the hot water tank.

What is it? should it be open or closed?

 

[chrishutt]

The pic's not clear enough to tell. Can you draw a diagram of the pipework?

 

[dampsquib]

As requested, 3 valves, A, B, C. Any Idea what each of them do, and what positions they should be in? Isnt A the Pump Bypass?

 

[ollski]

Looks like it's just the hw isolation valve to me....don't think I'd be brave enough to try and move any of them though.

 

[cozzmic]

Looks like to me a drain off point for the cylinder and part of the CH.
If the valve is tee'd off the cold feed to the HWC it is almost certainly a drain point, but a better photo would help.
Your coil ( the bit that heats the HWC) is not connected to the valve directly?

 

[dampsquib]

It is a gas boiler system. There is a heating coil in the top of the tank as backup should the boiler die.

So anyone else have an idea what the valves are, and more specifically what they do?

 

[chrishutt]

Valve A is the by-pass control valve. The by-pass is only necessary if you have TRVs on your rads.

Valve C on the diagram looks like it's on the return from the cylinder, so it's mainly for maintenance purposes.

Valve B looks like it's on the CH flow, and is also for maintenance. But why do you show that pipe connecting to the cylinder? Does it really do that? Doesn't make any sense.

 

[kevplumb]

methinks said drawing is a bit skew whiff

 

[dampsquib]

Yes, my mistake. the CH goes off somewhere, not straight into the tank (It was wearly when I drew the diagram!). So can I take from this that valve C should normally be closed? and Valve A (bypass valve) should be closed (no TRVs)?

thanks

 

[ricarbo]

I'm confused by the sketch, it can't really be like that. if the valve C connects to the heating coil on the cylinder (two 22mm pipes on the side of the cylinder, one above the other, at about one third and two thirds of the clinder height), then it could be to restrict the flow through the coil when central heating and hot water are on at the same time. The idea being to stop the cylinder hogging all the boiler output at the expense of the heating. I'd close the valve, carefully counting the number of turns, then try it at different settings. You can always put it back to how it was if you keep a note of the initial setting.

 

[dampsquib]

To stop anymore confusion, here's a new photo, and a new diagram. The only in/outs the boiler has are as shown. I've marked where I thnk the pipes may be coming from / going. Do i just have an odd tank? I'm beginning to think valve C needs to be open, otherwise how else would the Hot Water get to the taps?

[/img]

 

[ChrisR]

It's as ricarbo said - C is a balancing valve in the return to the boiler. Nothing to do with tap water.

B controls tap water nto the cistern, it leaves the top and goe where you've wrongly put "From boiler vent".

Where you've written "CH return" is the boiler vent and the small pipe to the left of it the Ch system feed.

Perhaps you should look in a book?! OR ON THE WEB. It took me all of 20 seconds to find this:

(for Expansion read VENT)