Weird one...

[Roger465]

I’ve recently started noticing a very strange, intermittent noise from (I think) my airing cupboard. This is directly above my head as I lie in bed, with a big hot water tank, pump etc. The house is only about 7 years old. Beneath me, in the kitchen, is the boiler.

I’ve only really noticed this as I’ve been sleeping very badly lately – as I’ve been lying there, trying to get back to sleep, there’s suddenly a noise like a valve clunking open, a 2-3 second rush of water, then the valve clunks shut again! May happen more than once a night – and, for all I know, during the day too.

It’s exactly like the noise a washing machine makes as it opens its valve, lets water in, then closes the valve again – just of shorter duration.

What the hell can it be? The heating hasn’t been on for months; no washing machines or anything on at night; and the boiler doesn’t come on to produce hot water till 6:00 in the morning

 

[Dan Robinson]

Crystal ball time again I see

What type of system do you have?

I'm assuming unvented cylinder and two two-port valves.

Maybe the pump kick pushing through the by-pass valve.

 

[Roger465]

I’m sorry, but I know nothing about heating and plumbing, so I don’t know what information to give you , so I’ll try to add a couple of photos. But from what you’ve said, I don’t think I stand much chance of understanding the explanation anyway

Untitled

• Roger465
• 30 Jul 2014
• 2

Untitled

• Roger465
• 30 Jul 2014
• 2

 

[picasso]

The next time it happens stick your finger in the tundish and see if its wet, if you dont know this is a tundish.

View media item 80421

 

[Roger465]

Is this the chappie? View media item 80435

 

[Armo74]

Is this the chappie? View media item 80435

Yes.

 

[jeff the gasman]

If you have a push button toilet and the flush valve seal is faulty this will cause exactly that sort of scenario.
Jeff

 

[Roger465]

If you have a push button toilet and the flush valve seal is faulty this will cause exactly that sort of scenario.
Jeff

Thanks Jeff, you've really got me thinking with that one, as I have three such toilets, all of which I’ve replaced the flush valves (Fluidmaster Button Cable Dual-Flush & Bottom Inlet) on recently (two about a year ago, but one only a month ago). As I’m fairly ignorant on these matters, could you possibly explain how a faulty valve in a toilet could cause this?

 

[fluxeyfingers]

If there is a slight trickle getting past the sealing washer at the bottom of the flush valve, the water level in the cistern will drop. When it drops low enough the fill valve will add a little water to bring the level back up again.

Flush valves are usually a bayonet fit so you could undo the valve, clean washer and seat with kitchen roll, and see if that cures the problem.

 

[Roger465]

If there is a slight trickle getting past the sealing washer at the bottom of the flush valve, the water level in the cistern will drop. When it drops low enough the fill valve will add a little water to bring the level back up again.

Flush valves are usually a bayonet fit so you could undo the valve, clean washer and seat with kitchen roll, and see if that cures the problem.

Oh yeah, even I know that… that’s why I replaced the valves on all 3 toilets, because they were all trickling into the bowl.

But this isn’t like that. Like I said, it’s a 2-3 second blast of water, like an electronically-controlled valve opening with a slight clunk, what sounds like a full-pressure rush of water, then clunk as it closes again.

 

[fluxeyfingers]

I’m sorry, but I know nothing about heating and plumbing,

As I’m fairly ignorant on these matters, could you possibly explain how a faulty valve in a toilet could cause this?

I'll leave you be then.

 

[Agile]

But this isn’t like that. Like I said, it’s a 2-3 second blast of water, like an electronically-controlled valve opening with a slight clunk, what sounds like a full-pressure rush of water, then clunk as it closes again.

So in what way is your noise NOT like a toilet valve opening for a couple of seconds?

You should have iso valves on the feed to each toilet.

I suggest you turn off the iso valves overnight and see what effect that has!

Tony

 

[Roger465]

So in what way is your noise NOT like a toilet valve opening for a couple of seconds?

OK, I seem to be getting into some kind of argument here, which was certainly not my intention. When I ask for an explanation, it’s because I don’t understand, and am trying to educate myself a little.

I’m not saying the noise isn’t like “a toilet valve opening for a couple of seconds”. I guess what I assumed, and therefore didn’t feel it necessary to say, is that if water trickles through a leaky seal into the pan, my experience has always been that the fill valve (if that’s what it’s called) stays slightly open all the time, allowing water to trickle into the cistern at the same rate it’s being lost into the pan.

So what I don’t understand is how such a scenario could bring about a sudden, hard, 2-3 second burst of water running through a pipe somewhere. I apologise for my monumental stupidity.

 

[Agile]

The old ball valves did open progressively.

But the modern fancy types open fully and close fully just like a solenoid valve!

I suspect that most people, like me, don't really understand how they work but just observe what the do.

There is also a possibility that your cylinder is discharging as that can be a similar effect. But that would normally only happen when heating up from cold which you are not doing in the night!

If you suspected that then put a strip of newspaper across the tun dish and if that was leaking it will be all wet in the morning.

All of this is very simple for a plumber or a knowledgeable DIYer.

Tony

 

[Roger465]

But the modern fancy types open fully and close fully just like a solenoid valve!

Mine don’t! If you let a little water out, the float slides down the shaft a tiny amount, and water starts to trickle in – just like a ballcock. Push it down slightly more, and the flow increases proportionately.

If you suspected that then put a strip of newspaper across the tun dish and if that was leaking it will be all wet in the morning.

I thought about that last night – then I had visions of bits of soggy paper getting down into the system etc… I’ll think of something like that though.