Squelching noise in pipes

[foxboy]

I have recently re-routed cold and hot pipes in the bathroom (about 3' only) but am now getting squelching sounds from the cold pipe when water is drawn elsewhere round the house. The cold is on main feed as is all the house (it's a bungalow) and the low pressure cold feed from the water tank has been stopped up. Any ideas

 

[felix]

It sounds like an airlock. Have you inadvertently created an inverted loop of pipe? There is no simple cure for this. Even if you can flush the air out, eg by turning a tap on full blast, it will keep coming back because your mains water supply has air dissolved in it.

 

[kevplumb]

couldnt resist


could always have a look

 

[foxboy]

cheers Felix, don't know what I've created but it's obviously the way I've soldered the pipe.. I just cut the pipe back and steered it from one direction to the other with two 90 degree elbows. The pipe is coming into the bathroom from the ceiling and it sounds like the water is dropping down the pipe rather than flowing smoothly..

 

[felix]

I can't see your pipe layout so I'm guessing here. It sounds like mains water comes in at ground level (as it must) then goes up into the loft before dropping back down into the bathroom. That's an inverted loop but it doesn't matter because air will escape from it whenever the ball valve opens in the cold tank. Am I right so far?

Since you can hear water falling down inside that vertical pipe it must be full of air. This air should be escaping up to the ball valve but there's something in its way. Did you put a new horizontal piece of pipe at the top? Is it sloping the wrong way? Look at the pipe run and ask yourself if there's an uphill path all the way to the ball valve.

 

[foxboy]

Ahh, this could be the problem. The cold feed is going up into the loft but then coming straight back down into the bathroom. It's not going into the cold water tank. The low pressure cold feed from the tank has been stopped up. I could feed the bathroom by connecting back up to the tank but this would be servicing the bath, sink, toilet and lastly the shower. If I'm in the shower and any of the first three are used it would interrupt the flow wouldn't it?
If I made the pipe run into the bathroom more direct do you think this might solve it? At the moment it's a bit if a zig-zag

 

[doitall]

Have I missed something or our you fully mains cold water now, and the storage tank only feeds the hot water cylinder.

If so the dead leg you have capped off is against water board regulations and must, be capped off as close to its supply as possible, e.g. the tank or where it branches

 

[Newboy]

I might be missing something here but just out of interest - where is the mains feed to the storage tank, why not just tee off from the pipework in the loft to your bathroom rather than re-route ?

 

[foxboy]

The dead leg is capped off close to the tank, and yes everything is on mains feed with the cold water tank just servicing the hot water cylinder. The supply to the bathroom is tee'd off the supply to the cold water tank although does bend through two right angles (horizontally not vertically) before dropping down into the bathroom...
So I'm still confused
It all works fine except for the strange noises

 

[felix]

The mains supply goes up to the cold tank ball valve. As long as this valve opens at regular intervals any trapped air in the inverted loop will escape. The problem must lie in your new pipe run from the tee-off point down into the bathroom. If you have even the slightest uphill gradient in any of those horizontal sections - that's uphill in the flow direction - you will get an airlock.

You could have left your bath, basin and toilet supplies alone. The correct way to supply cold water to a mixer shower is direct from the tank on its own connector. There's no great difficulty in cutting a hole in the side of the tank to put a connector in - unless you have an asbestos cement tank! You can even tap into the pipe feeding cold water to your hot cylinder though you MUST do this at a point higher than the top of the cylinder.

Having read your posts carefully, I have a few questions.

1) What kind of shower have you got? If it's a mixer, where is it getting its cold water? You can't use mains water on the cold side and tank water on the hot side. It will work very badly, if at all, and the water board won't like it one bit.

2) Did you swap the low pressure ball valve in the toilet for a high pressure one? If you're lucky you'll only need to change the nozzle inside the valve or fit a restrictor washer. If you're very lucky you'll find the part you need attached to the ball arm - and the fairies from the bottom of the garden will have sorted it all out before you've finished reading this!

 

[foxboy]

Thanks Felix I appreciate all the advice. I might have put a slight uphill gradient in without realising. I'll check in the morning.
It's not a mixer shower it's just an electric. I've not fitted the new toilet yet so I've not even got to that problem
It's a continental flush type. I take it from your comments that they are designed for low pressure, so some adjustments may be necessary..
Thanks again for the help

 

[doitall]

Mains cold will not air lock, and I've yet to see air as a problem with any mains supply however low the pressure.

Look elsewhere like the hot or a leak

 

[foxboy]

Felix you are a genius! I've been back into the loft today and yes you was quite correct, I had put an uphill gradient in the pipe run to clear a joist I have changed the pipe run slightly now to keep it all level, and hey presto - No more squelching
Thank you. and big thanks to the forum administrator for providing this service

 

[felix]

You're welcome.