@grantmethestrength how did you adjust the pump?

@jamespa the paving slabs are not cemented down just weight of the hp holding everything in place. Hp not fixed to slabs, slabs not fixed to each other. There is a gap between the slabs and the wall.

Update: I went outside during the non eco mode hw run and it’s the same noise outside that I can hear inside. My guess is the French doors are transferring some via the large double glazed units. I also had a feel around the primaries insulation on the wall and can feel the vibrations, they are very strong where they exit the back of the pump, the flexis are reducing it but not totally. It’s almost like it needs another section of flexis to reduce it fully. Also the brackets are getting hit with the vibrations as well.

@adamk I have a Grant Aerona3 so it is a physical jumper switch on the unit the you have to flip up or down in a certain combination that gives you High,Medium and low. Mine was on high and I was getting over 40 l/min, medium was over 3p l/min low is pretty rock solid at 28 l/min. If I try and shut it down at the flow meter the system gets very noisy so for now 28 is the magic number for my system!

Posted by: @adamk

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@jamespa the paving slabs are not cemented down just weight of the hp holding everything in place. Hp not fixed to slabs, slabs not fixed to each other. There is a gap between the slabs and the wall.

Update: I went outside during the non eco mode hw run and it’s the same noise outside that I can hear inside. My guess is the French doors are transferring some via the large double glazed units. I also had a feel around the primaries insulation on the wall and can feel the vibrations, they are very strong where they exit the back of the pump, the flexis are reducing it but not totally. It’s almost like it needs another section of flexis to reduce it fully. Also the brackets are getting hit with the vibrations as well.

OK

The heat pump doesn't need to be fixed down, the rubber feet ensure good contact area.  However loose slabs are a potential soucce of noise or amplification (but perhaps not the problem) because they are rigid and so make contact in only a few places.  personally I would have put a layer of mortar in between, as my installer did.

If it needs another run of flexis then thats an easy solution given your pipework is both vertical and external.  The brackets shouldn't be getting any significant vibration and there is no way pipework noise should penetrate double glazed units.

It could, as @adamk suggests, be something to do with flow rate/internal pipework.  My pipework is actually quieter than it was with my boiler, I think because, although the water velocity is higher, the system is better bled.  |I did spend a month bleeding one radiator daily.  Despite the presence of an auto bleed valve at the highest point air would collect in this particular radiator, and never got flushed through to the auto bleed valve.  During the first month of operation of any heating system after a refill dissolved air comes out of the water, and will collect at high points.  Your description of the sound doesn't sound like this however.  Check the flow rate in live monitor on the HP appliance interface.  It should be in the region 500-1200l/min.

It could be the primaries are rattling against the caging as they exit the unit.  Touching/holding them will ferret this out.

@jamespa That flow rate sounds rather high James! Regards, Toodles.

Posted by: @toodles

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@jamespa That flow rate sounds rather high James! Regards, Toodles.

Er true, it should have read l/hr!

who do i contact about getting stuff sorted when the installer doesnt seem to be doing anything constructive about getting the sparks back to fit the correct breakers?

Posted by: @adamk

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who do i contact about getting stuff sorted when the installer doesnt seem to be doing anything constructive about getting the sparks back to fit the correct breakers?

The answer contractually is whoever you contracted with for the the work which included the fitting of the breakers (normally whoever you paid for same), 'privity of contract' being a basic tenet of contract law.  The answer practically may differ.  

IET regulations allow a fair amount of discretion for the electrician (because the regulations assume that the electrician is a professional) and crucially rarely require that 'old' installations' to be updated to latest standards.  So be aware that sparks may argue and may be right to do so.  Of course equally they may not argue and/or may not be right to do so. 

What's wrong with the breakers and what is the authority for them being 'wrong'.

also if the primaries inside the house are clipped against the ceiling trusses, i have a lowered ceiling so have a void where the pipes run, would it cause the humming noise from the compressor to be heard? to my mind it shouldnt matter as most houses have pipework resting against trusses or through them. surely the vibration suppression should be managed to externally so the pipes internally dont vibrate.

Posted by: @adamk

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m. surely the vibration suppression should be managed to externally so the pipes internally dont vibrate.

Yes thats the whole point of the flexis as regards transmission of externally generated vibration to the indoors.

however its possible, I suppose, that pipe vibration is generated indoors if there is air blockage and a high velocity

I suppose the presence of a liquid could cause a humming noise from the compressor to be transmitted, but I would think its unlikely its audible.  Certainly mine isnt, at least its not audible to me.  Do you know the noise is from the compressor?

@jamespa pretty sure, unless the water pump makes a humming noise outside when stood about 2m from the unit. I can hear for instance when it ramps up from I’m guessing tick over. Looking at the app when it’s off power is about 9w when it’s just ticking over about 58w which I would think is the water pump and still silent, but then when the unit draws say 750w I can hear some noise but only maybe in the kitchen and upstairs bedroom, when it’s near flat out I can hear it in the lounge whilst I’ve got the tv on.

Water pump will certainly make a hum (which could conceivably be carried by the pipes) but the description does sound more like the compressor.  It's easy to take top and sides off to be certain if you fancied doing that.  Drawing 750 W mine is inaudible inside so something sounds wrong, either something amplifying/transmitting the sound or a compressor that's more noisy than it should be.  At full chat, which really only occurs when recovering from defrost, I can hear mine inside but it's quieter than my fridge so not obtuusive.   It's right next to a window.  What does your installer say?