Help - it is midnight on Sunday and my tap is making a very wierd noise

[Lunenburg]

I am lying in bed and the mixer tap in my ensuite keeps making an intermittent shushing noise with a slight bang. Probably every two minutes or so. No one is near said tap and it was last used an hour ago.

I have an unvented (pressurised) cylinder on the system and am worried that either the tap or the cylinder are about to fail and flood the house.

That may sound silly but I woke up 9 months ago to a flooded house caused by the valve on the cylinder (Megaflo) failing and I don't want a repeat.

Does anyone have any idea why my tap would bbe making such a strange noise?

Most modern taps have a filter/flow control on the end of them and they can get a bit flakey if they get corroded (soft water) or furred up (hard water) and start letting through big gobs of water. It might be that sort of activity that you're hearing.

Or a poltergeist.

Turn your water off and call a plumber in the morning

Hope it's not the latter Pickachiew

I thought about the flow control but the noise sounds as if the tap is under pressure. It hasn't been used for well over an hour but just keeps belching out this strange shush noise followed by a bang.

When it first started I ran the hot and cold tap together to see if there was some kind of air lock but that didn't make any difference.

Was going to suggest leaving it running for 10 minutes but see you've tried that!

If it's a mixer tap with a joystick, the ceramic cartridge is probably leaking internally. They do that. Luckily they look so flashy stylish that people don't mind.

The cold water will be at high pressure, straight off the watermain (mains pressure goes up at night).

The hot water in an unvented cylinder has safety controls to prevent the pressure going too high. I expect it is periodically releasing water through the safety valve when the leaking mixer sends it too high.

If you have an indoor stopcock and you know where it is, you could turn it off overnight.

Thank you Piglet John

I think that both the hot and cold water pressure are pretty similar.

I had a problem when this Burlington tap was first installed and after fitting three replacements, Burlington came out to see what was wrong. They identified I had very high Cold Water pressure (9 Bar) and said I needed a pressure reducing valve. My Plumber fitted that and my cold pressure inlet is now reduced to 3 Bar. I think the pressure valve on the Megaflo is also set to 3 Bar although I am not sure if that controls input or output pressure.

The tap has worked perfectly since that valve was installed 6 months ago, until tonight.

I have noticed an hour ago though, that the Megaflo doesn't seem to be filling when I draw off a little hot water. It is also slightly dripping through the bund.

The tap is now making this noise every minute or so and getting louder.

Do you think it is the tap that is the problem, or could the tap be highlighting that there is an issue with the Megaflo?

After te flood last year, I am terrified of the Megaflo going wrong again.

I have turned off the boiler so that the water in the megaflo isn't heating up and turned off the inlet valve to the megaflo, just in case the pressure valve on that is about to fail.

That is what went wrong last year. Megaflo came out to do a routine service, replaced the all the valves and then the pressure reducing valve failed a week later (this was before I fitted the pressure reducing valve to the mains inlet).

It would be best if your pressure-limiting valve on the main inlet controlled all the water, withe the megaflow's own limit being slightly higher (so it would only operate if the first one failed). Quite likely that is already done.

You say the Meg is dripping, so presumably has exceeded its own limit. This can also happen if the Meg air bubble needs topping up, which absorbs the expansion when water is heated.

Some pressure limiting valves (like my Caleffi) have a pressure gauge on them, which tells you the pressure in the pipes, may be useful.

Your circumstances are fairly unusual. Provided your plumber is qualified to work on unvented cylinders, and local, s/he should be more familiar with the conditions.

I'm not keen on ceramic joystick taps, if that's what you have, you might consider changing to one with two knobs in a Y shape. Mostly when they internally leak its because the cold pressure is high and the hot is from a loft tank.

There might be service valves on the pipes supplying the taps, that you can turn off. Unfortunately the braided flexible tap connectors also sometimes fail. They are almost invariably unbranded.

Thank you Piglet John

I eventually found a plumber (like Hens teeth in this area) prepared to come out this morning.

The tap stopped it's antics an hour before he arrived.

He could find nothing wrong with my system and is as puzzled as I am about what happened overnight.

The new pressure reducing valve is a Caleffi with the guage and is fitted into the pipe run on the house side of the stop cock. I checked that several times during the night and it didn't waver from the 3bar it is set at.

The tap,is a Burlington, so supposed to be a really good make, but after all the problems I have had with it, not a purchase I will be repeating.

The plumber today reset the Megaflo air bubble. Interestingly, I have done that several times myself and have never had the quantity of water pouring through the bund, that we saw today. The valve was new last year and was extremely difficult to turn and hold open today.

After only two hours sleep (the noise was loud even through the Ensuite door) I am extremely unhappy with Burlington. I tried phoning them this morning and have written this evening. I am asking them to replace the tap again and pay the Plumbers bill to fit the new one.

Not holding my breath, but I am hoping for no repeat performance this evening !!

Thank you for your help. In the wee small hours it calmed my anxiety enough for me to get some very brief sleep.

"The tap stopped it's antics an hour before he arrived."

I suspect that's because the overnight high pressure (when no-one is using it) dropped at getting-up time.

If the gauge never wavers, are you sure it isn't stuck?

I cant be sure the guage isn't stuck.

I did turn it up,to 4 bar this morning and then back down. The guage recorded the pressure increase and decrease.

Is there any other way to test it?

I think that's fine.

If the Meg is set to 3, I'd turn the Caleffi down a bit. 2 and a half, maybe? That should mean the Meg will never reach overpressure unless the Caleffi fails.

If your shower is noticeably weak, you can turn it up again.

Thank you Piglet John.

I literally only had 2 1/4 hours sleep last night so have crawled up to bed. Hoping for a better night tonight.

Just to reiterate how much I have appreciated your help !!