Can anyone explain this pipework?

[Fordy81]

I hope it's clear from the pics. I can take more if not.

I have an isolation valve that is closed, and I'm not entirely sure why! It's the vertical one in the middle of the picture.

I also have a horizontal one towards the bottom of the picture that was only half open. I've fully opened it because I thought it should be. :/

The thick pipe at the top right goes up to the pump. The one on the left of that goes up to the 'de-aerator', I think it's called. Should these valves be open?

Untitled

• Fordy81
• 25 Jun 2014
• 2

Untitled

• Fordy81
• 25 Jun 2014
• 3

Untitled

• Fordy81
• 25 Jun 2014
• 4

Untitled

• Fordy81
• 21 Jun 2014
• 2

 

[Terry lambert]

The vertical isolation valve has been fitted as a by pass, your three port will work fine without it as it is, although regs would require an auto bypass.

The horizontal isolator from the cylinder return should be open, it's being used as a balancing valve, but isn't really suitable.

The pump valves should be open.

You wouldn't use isolators for the purposes they are being used here, as they are too restrictive and will eventually weep

 

[stem]

I also have a horizontal one towards the bottom of the picture that was only half open. I've fully opened it because I thought it should be.

As has already been said it looks like a by-pass that is there to allow water to circulate through the boiler if all of your radiators are equipped with thermostatic radiator valves which could theoretically all be closed at the same time. [In reality there should be at least one radiator that is not equipped with a TRV, but sometimes in older installations without a wired room thermostat TRV's are fitted to all of the radiators]

The 'by-pass' just needs to let a small amount of water by, so is normally only slightly open. Now you have fully opened it, you will probably find that in the winter that the radiators won't get as hot, because the water will be now be flowing through the by-pass instead of through the radiators. I would suggest that you put it back where it was.

 

[Fordy81]

Thanks for the replies.

I'm confused now though as one says it should be open, the other says partially open.

 

[Terry lambert]

Stem is referring to the veryical valve, I am referring to the horizontal valve on the return from the cylinder

 

[Fordy81]

Stem is referring to the veryical valve, I am referring to the horizontal valve on the return from the cylinder

Thanks Terry. I never touched the vertical one, that is still shut. It was the horizontal one that was half open but now fully. I should leave everything as it is? Or put the horizontal on the return back to half open?

 

[Terry lambert]

Leave it open, the 15mm pipe and internal bore of the isolator is more restrictive than I would like as it is

 

[Dextraneous]

I believe there's an old addage about "if it ain't broken..."

 

[Terry lambert]

I believe there's an old addage about "if it ain't broken..."

Where's your sense of fun and adventure