75ZT Community

Any plumbing experts please?

During filling the bath, the pipework seemingly all over the house starts vibrating so much so that you can see ripples in the bath water and feel the vibration thorugh the floors This goes on for several minutes after the bath is filled. Occasionally it can be mitigated by turning on a cold tap elsewhere in the house but as soon as that tap is turned off it starts again.

I've tried the old dodge of turning the rising main stop-tap a quarter closed but no difference.

Any ideas gratefully accepted chaps

Sounds like an airlock in the heating system. Bleed all the radiators and the boiler.

Do you have a combi or a hot water cylinder? If a cylinder, do you have a header tank? If the last, then the rubber on the ball valve in the header might be worn.

Thanks Chaps. We have a cylinder, fed from the cold water tank in the loft.

I'll bleed the heating and get up in the loft and examine the Portsmouth valve in the cold water tank.

does it happen with just the Hot tap on ??

If no combi , then bleeding the rads should not help as they are on a separate circuit ..

When we have had a similar prob i have back fed/filled the hot water circuit from the mains with a pipe linking the down stairs hot and cold Taps.

Even easier if downstairs has a mixer tap ??

C.

It is just the hot tap that causes it Chris.

I can't see anything wrong with the Portsmouth valve in the loft tank and I've bled the heating system on spec anyway so I'll give your idea a try

Worth a go , basically you are just refilling the hot system using mains pressure up through the hot tap through the hot tank and into the storage tank forcing any air up and out ..

You will be bypassing the tank valve , but your overflow should cope if you fill it for too long..

Sounds very much like the ball valve on the Domestic hot water tank in the loft ( thats the larger of the two if you do not have a pressurised C/H system )

takestock wrote:Sounds very much like the ball valve on the Domestic hot water tank in the loft ( thats the larger of the two if you do not have a pressurised C/H system )

I took it apart Dave and it looked OK

When the hot tap is running and the noise is present nip up into the loft and push the float fully down see if it stops the noise, and then lift it up fully If either of these actions stop the noise This and the fact that a cold water tap turned on stops the noise proves that it is on the cold mains side of the system. It can only be one of two things, the ball valve or the main stoptap.

If you think about it, these are the only parts that move that will have running water passing them under pressure. Another trick is to open the main stoptap fully against the stop.

The anomaly is that it doesn't happen with the sink and basin taps, this could be due to less volume of water being drawn through the domestic hot water tank, may be worth turning basin and sink tap on to see if it happens then

Well, I know the main stop tap was replaced within the last couple of years so it might be worth replacing the ball valve on spec.

You are right that it doesn't happen with a basin hot tap on. As you say, probably not enough throughput.

I've had ball valves (Portsmouth Valves) start to make a noise as the rubber washer aged. Not sure if it was wear or hardening. In any case, they didn't look bad, and didn't drip. But replacing the washer fixed the problem.

I don't think you have to replace the whole valve, just the rubber in the piston.

OK Duncan. I guess they'll be a uniform replacement size then?

Years ago they were, but I'll be honest I don't know if there are newer versions. The ones I fixed all had brass pistons. The washer looked impossible to get out because unless you already knew, you wouldn't guess the end scewed off the piston. Learned that after my dad swore at one a lot. First DIY job I did for my wife (was my new girlfriend at the time) was doing one of these.