What is causing it??

[Linc]

My daughter has a problem with her CH in her rented accommodation.

Basically, what is happening is that every 5 or 10 minutes or so, there is a 'bang' in the system. The leasing agents sent round a 'heating engineer' who stayed 15 minutes, didn't hear a bang and suggests that my daughter is losing it!

I went there last night and with just the CH on, there is no noise. As soon as the HW switches on, it 'bangs' once. I found out that by pushing the lever under the 2 Way(?) valve in the cistern cupboard to the right then releasing it, the bang occurs again. There is resistance when I push the lever but with the HW OFF there is no resistance and the lever just 'wiggles' (sorry for layman's term) easily. I can make the bang noise each and every time I push the lever to the right whilst the HW is calling for heat.

Anyone any suggestions as the 'engineer' is returning tomorrow and I want to at least come up with a possible cause.

Many thanks!

 

[corgiman]

I have come across this a few times, especially on myson powerheads

not much can be done except clip the pipe firmly, the spring on em is as hard as vinnie jones after a pint.

has the valve got a white head on it?

 

[Linc]

Sorry...forgot to mention. Pump is set to '2' and downstairs rads are cold with CH ON

 

[Linc]

The valve has a silver coloured cover. Is that what you mean?

 

[corgiman]

ah its a honeywell

well I never had one of them do it, but the tower ( a honeywell rip off) does.

is the pipework clipped up well?

 

[Linc]

Wherever the pipework is near say a wall, it is fastened to it but at point of valve there is no fixing. (obviously I suppose - nowhere to fix)

A guy at work (who professes plumbing knowledge) says I shouldn't be able to feel pressure on the little lever I mentioned when system is ON and valve is Open?? I don't know but I have checked mine at home and it is loose with no 'pressure' at moment (CH & HW on)

 

[corgiman]

I would not worry about that its when it returns to the closed position that is causing the bang

and u have heard my opinion hopefully the others may have something to add

or tell the "engineer" what you think it is then show him

 

[Linc]

OK..and many thanks corgiman..for your suggestion and quick response. Much appreciated

 

[corgiman]

great aint I

ask anyone they will agree

NOT

 

[Agile]

The bang occurs because when they are fitted ( correctly ) the flow through them pushes the ball closed against the valve seat.

Mechanical loose movement ( backlash ) causes the ball to get pushed very rapidly for the last couple of mm onto the seat and that shuts off the flow very rapidly and the shock wave reverberates through the pipework.

Fitting a new valve MAY solve the problem but it also depends on the design of the system and pipework layout and other variables.

I dont see why your daughter is so concerned about the odd bump occasionally. Why doesn't she turn up her iPod a little to mask the noise?

Tony

 

[simond]

Am I mistaken here?

But I thought all Honeywells work moving the ball against the flow when they open? That's why you get a big clonk when they are fitted the wrong way round as they shut?

 

[ChrisR]

It's a 3 port Simond

I've had a new Drayton do it (moving rubber cheesewedge type)
Fix them pipes. (As Corgiman said 4 minutes after the question!)

 

[Agile]

I had assumed its a three way as only one valve has been mentioned.

Reading again it could be a two way fitted the wrong way round although I think its unlikely as he says it does it when he puts HW on. That would indicate a non conventional system perhaps one wired to give priority to HW which closes the Ch when HW is selected.

We dont really know!

Tony

 

[Linc]

Thank you all for your suggestions/advice. The 'engineer' came today and it is the valve that is causing the problem. He has organised replacement. Meanwhile, he has fixed it in the 'Manual' position so that both CH and HW are always ON together. There is now no 'banging'.

It is a 3 Port 2 way valve (Honeywell) and it would appear that it is sticking on the HW side and being forced open which is causing the bang.

By the way, Agile...my daughter lives away from home and is 27. She hates Ipods and the bangs are occurring every ten minutes or so from system switch on. The cistern cupboard (where the valve is) is in her bedroom and she was finding it difficult to sleep with the constant banging caused by the faulty valve (bearing in mind that the system switches on about 6am and she (lucky person) doesn't have to get up till 7.15am) I think you'll agree, it isn't the sort of thing you would wish on anyone who simply wants a night's sleep!