New ballcock question

Looking at various items on eBay, I'd say that that (part 1) is exactly what I have bought. TBH, I didn't know there were various kinds available - I was just happy to be able to get a replacement locally on a Sunday afternoon :-)

Now I know what to get, thanks.

Actually, I've another question, if I may? The header tank has an overflow pipe (of course), but has a piece inside the tank at 90 degrees that looks like it should dip into the water. It didn't dip into the water before I started messing, but I can't imagine that it serves any purpose without doing so. Should I adjust the water level so that the tip is submerged?

Might be dirt in the inlet valve

I suppose that would be a simple enough thing to check.

That makes sense. I wonder what it's for, then? The CH header tank doesn't have anything like that. A bit of a mystery.

I did think of that, but then whoever put the bend in the pipe didn't follow up the precautions with paying so much attention to making sure that the jacket was well-fitted. I think I'll stop worrying about it :-)

Yes you can relax, BTW, I'm a retired plumber.

I thought I detected a sense of expertise, which is much appreciated :-)

You're welcome.

Yes first thing to try is turning the isolating valve down as far as is practical. Have a look at the "hole in the bottom" of the valve. If it has a female thread you can screw a short bit of plastic pipe into it which may help matters. This bit of pipe used to be supplied with the valve in days of yore

You could try bending slightly the brass arm the ball valve is on.

This sometimes changes/stops/reduces the wave running back and forth across the tank and might stop it.

Or fit a cylindrical float in place of the ball.

Or hang a small weight on the ball arm near the ball. If this corrects the problem, fix it on permanently.

Yes indeed, one that goes underwater is the way to go. I need one for my toilet cistern as well as it has the wrong valve size, ie its for a mains feed not a gravity feed and so it constantly sounds like a babbling brook. Brian

There is no thread, and the hole isn't even proud from the surface. It's just drilled into the block, so that water just goes everywhere.

Yes, I don't think it would take much to disturb the equilibrium of the whole thing. I expect it can only be oscillating like it does because conditions are just right :-)

The only difference is the jet is a bigger hole for gravity fed ones. They won't close against mains pressure.

Oh yes they will:-)

I have just connected an old gravity fed cistern to a 5 bar mains supply. Shuts off OK but *howls* as it reaches the close off point.

On dipping tubes... I thought these are not permitted on mains feeds due to suck back contamination risks. The way round was a collapsible plastic tube.