Noisy vibration in hot tap

[Bellx15]

I hope no-one minds me starting a new thread here - the one I hijacked earlier is maybe a bit misleading by now.

My problem: Had same kitchen sink and mixer tap for all the time we've lived here - 10 years, and probably 20 years since installation.

Just recently the kitchen hot tap has started growling and vibrating once the water reaches its working temperature. You can feel the vibration in the tap handle. Leave it growling for a few seconds and it establishes a rhythm - starts to sound like a donkey. Turn it up a bit, or down a bit, and the noise changes or disappears.

New washer fitted - hot and cold valves swapped over - still the same in the hot tap. Not the cold. (Previously I'd thought the swap over had fixed it).

No other taps in the house make any noise at all.

Could it be just that both valves are worn, but that this is only apparent when there is hot water running past them? Any further ideas would be greatly appreciated.

 

[Bellx15]

Well, well. What do you know.

I just had the idea of taking the hot tap valve apart and packing the internal thread with Ptfe tape. The first attempt made little difference, so I wrapped some more around it. Must be about 40cm altogether. The problem has vanished!

I don't think I have found the root cause of the problem, though. Could it be excessive water pressure in the hot system, and if so, can it be reduced?

(Worcester 28i combi system)

Thanks in advance.

[I should add, perhaps, that the effect of the tape wears off after a few uses, as the thread cuts through it, of course, so it isn't a long-term fix. It might help with diagnosis, though].

 

[Henno82]

sounds like you may have temporarily solved this problem as it may come back in a few days, weeks or even months

 

[Bellx15]

Yes, it's back. The tape just had a very temporary effect.

 

[Henno82]

Thought so, try changing the tap itself? this could be faulty

 

[Bellx15]

I'm toying with the idea of doing that - tap revivers, I thought. I was just hoping to find out exactly what the problem is. I might find it still there with new taps. Either the water is too hot, perhaps, or the pressure is too high? I don't know why either would have changed, though.

I realise I'll have to try them though. Just trying to get a diagnosis.

 

[Henno82]

i dont think the pressure will make it like this, have you tried turning down the temp on the boiler so you can eliminate this?

 

[Bellx15]

You might be right, but I don't think there is a temperature control for the dhw on this boiler. Just on the central heating water temp.

I just turned the stopcock half-way closed, and the noise stopped completely. The flow is pretty slow, but there is hot water, and no noise!

Does this help with diagnosis?

PS I did replace the dhw thermistor a couple of weeks ago, just to make sure.

 

[Bellx15]

Just adding information as I get it - hopefully someone will know what is causing this.

When the hot tap is making its noise and vibration, I slowly turn the under-sink stopcock down, and there is a very critical point where it stops the noise from occurring.

This is the mains stopcock - not directly connected to the hot water tap.

 

[Henno82]

so it sounds like it could relate to pressure other than that i have nothing else i could offer

 

[justlead1]

Hi. The taps done a couple hundred thousand miles with out a oil change. The wear allows movement, as does the expansion due to heat. With the pressure /flow the movement is fast and the oscillating produces the noise. Try new head gear. Good Luck

 

[Bellx15]

Yes, this sounds very reasonable. Thanks. Many thanks to all. I really appreciate the feedback.

I'll get some revivers and see what happens. Any particular makes recommended?

 

[Henno82]

have you tried revivers yet Bellx15? how you getting on with this?

 

[Bellx15]

Yes - just had them by post today - total cure.

Thanks for all the help, everyone.

 

[TerryH]

Everything you say points to a pressure related problem. If it is an old tap and the combi. is a newer addition, then the pressure will have increased from (presumably) a gravity fed system to a mains pressure system. Perhaps the time has come to change the tap for something more suitable for a high pressure system; fit a ball valve to the tap hot feed and reduce the pressure or buy lots of PTFE tape

 

[morseman]

We have the same boiler as you and recently the same problem.The boiler is about 5 yrs old and the taps at the WHB are about 8 yrs old.All was well until this January when the Water Board turned off the supply for about 5 hours, on resumption of supply all taps in the house were"airlocked" they cleared eventually but the HW tap at the bathroom ( the boiler is located in a cupboard about 2ft away)makes a terrible noise at about mid travel.The noise disappears at reduced flow or full bore.The taps were cheapos from Argos and probably quite well worn now ,so it looks like new taps are required here.

 

[Plumbstar Tom]

that would be my suggestion as could be a worn jumper or like

Get some branded taps to get some quality

 

[noleaksihope]

renewing the washer & reapplying silicone grease to a dry jumper thread usually does the trick.