Posted by: @james-chattaway

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Hello all,

I’ve just had an arotherm 10kw installed in August and now the heating is on more consistently there is a noticeable flow noise coming from the airing cupboard, particularly around the filter

I had a 3.5Kw arotherm the installed earlier this year, so heating only been running 24/7 for the last week.  I have no significant noise at all.  I also have a mag filter.

Posted by: @james-chattaway

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particularly around the filter

The video in the link mentions a direction arrow, which I assume is pointing in the correct flow direction.

It also mentions a bypass valve to bypass a clogged filter. The noise certainly sounds like flow passing through a restriction which is likely occurring to overcome the bypass valve... clean the filter.

I also have no noise from my arotherm. 
my neighbors boiler is noisier.

@singlespeed 

This sounds pretty quiet to me.  Is it disturbing you.  There is bound to be a bit of noise where water passes rapidly through a fine filter!

Posted by: @singlespeed

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The noise certainly sounds like flow passing through a restriction

Yes indeed that is exactly how it sounds. Water rushing, like a partially opened valve with too much flow or deltaP through it, or other restriction.

Vibrations from this are transferred to the pipes which then act as a very large loudspeaker, so it can be difficult to pinpoint the source by ear.

A possible culprit could be a partially opened DHW 3-way valve, or another partially opened valve somewhere. 

@jamespa 

I'm slightly deaf and thought it sounded pretty awful.

It's a 100 micron filter which finner than most, so it's going to trap quite a lot of debris; especially if theres old pipework and radiators in the system. Having the bypass valve built into the filter body means the heatpump won't see a clogged filter as the flow passes through the bypass valve. But that would mean the system is nolonger filtering the return to the heatpump unit.

As it appears back flushing the filter is a simple job, I'd be inclined to do it. It may cure the noise problem and if it does, the flow will once again be going through a filter which will protect the heatpump again.

Posted by: @singlespeed

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@jamespa 

I'm slightly deaf and thought it sounded pretty awful.

It's a 100 micron filter which finner than most, so it's going to trap quite a lot of debris; especially if theres old pipework and radiators in the system. Having the bypass valve built into the filter body means the heatpump won't see a clogged filter as the flow passes through the bypass valve. But that would mean the system is nolonger filtering the return to the heatpump unit.

As it appears back flushing the filter is a simple job, I'd be inclined to do it. It may cure the noise problem and if it does, the flow will once again be going through a filter which will protect the heatpump again.

 

As you correctly infer you dont want a bypass valve - the filter is there for a purpose!

I flush mine about twice a year.  Its getting better as the rubbish is cleared out of the system.  Once it got so bunged up it stopped the heat pump working,

Thanks for all the feedback. The pipework and radiators are all brand new so I'd expect there to be very little in the filter (please correct me if I'm wrong). I will double check the flow direction and ask the installer to backflush tomorrow. 

The noise is louder than I was expecting which is why I started this thread, having not heard another heat pump in the flesh. I can hear it across the landing with the doors shut, and particularly in the bathroom that backs on to this cupboard (though I appreciate the hard surfaces will echo). If it's normal then I will look to add some additional soundproofing to that cupboard. 

I know the flow rate is higher on the 10kw, and also fixed, so maybe that is one of the causes. 

Posted by: @james-chattaway

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Thanks for all the feedback. The pipework and radiators are all brand new so I'd expect there to be very little in the filter (please correct me if I'm wrong). I will double check the flow direction and ask the installer to backflush tomorrow. 

Fair enough, still worth checking, I suspect muck gets in somehow!

Posted by: @james-chattaway

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The noise is louder than I was expecting which is why I started this thread, having not heard another heat pump in the flesh. I can hear it across the landing with the doors shut, and particularly in the bathroom that backs on to this cupboard (though I appreciate the hard surfaces will echo). If it's normal then I will look to add some additional soundproofing to that cupboard. 

That sounds louder than it should be unless the cupboard is acting as a sounding board.

Please let us know how you get on tomorrow.

The installer visited yesterday and suggested the noise was pretty normal but through a combination of flushing the mag filter, cleaning the mesh filter on the shut off valve (which did have a surprising amount of stuff in for brand new pipework) and opening an AAV which had been closed, the flow noise is now pretty much silent which is a great result. 

Also noticed the power draw on the vaillant app sits around 40w when only the circulation pump is running whereas it was 80w before, so maybe this is another indicator of an issue if anyone is fault finding in the future.

Thanks for all the help