Welcome to the forums @cally-m – can you please post a photo of the pump you think is responsible for the noise? I'd like to confirm whether it's the distribution/circulation pump or whether it's the ASHP unit itself. What's also not clear is whether the noise is coming from inside the house or it from the heat pump outside?

Posted by: @cally-m

RE:

Good morning, we live in Yorkshire and have just had a Grant Aerona 3 13kw ASHP fitted to replace an old oil system. First impressions are good - house is steadily warm but flow of water in radiators seems cool and not up to 45degrees so if we have a colder spell not sure how that will pan out, hot water is excellent and plentiful, initial energy consumption appears ok although weather is very mild . however, the main issue is the noise coming seemingly from the pump, making a terrible vibrating noise in the house when on - particularly loud when on defrost mode. The noise is approx 50db and reverberates through the house, not an issue during the day but at night is terrible so we have to turn the whole system off to be able to sleep. the installers say its a Grant issue, Grant say the pump should be silent (in the house) and must be an installation issue.

Can anyone advise me on this issue - when I say pump I mean the actual pump sending water around the system not the fan noise outside (apologies for laymans terms; no doubt we will learn) thank you!

 

This sounds like a plumbing/pipework issue rather than a heat pump one.  

If your ASHP is operating on weather compensation then the radiators will be cooler when it's warmer outside and will heat up more when it gets colder.  That's normally the most efficient way to run an ASHP.   

@editor We think the issue is some form of vibration within the heat pump itself - we think possibly the water circulation pump that is inside the air source heat pump unit? And the vibration is then turned into noise within the house.

I believe it's an all in one unit with the heat pump and circulation pump all in the same unit.

The pipes coming out of the heat pump outside are vibrating/shaking which then produces noise in the house.

@cally-m if it's vibrating in the unit it is probably an issue with the baring inside of the pump or the impeller. Something is unbalanced.

I expect it's a contained unit, so the whole pump would probably need to be swapped out. It would be very easy for anyone checking to confirm by simply putting their hand on the pump.

Posted by: @cally-m

@editor We think the issue is some form of vibration within the heat pump itself - we think possibly the water circulation pump that is inside the air source heat pump unit? And the vibration is then turned into noise within the house.

I believe it's an all in one unit with the heat pump and circulation pump all in the same unit.

The pipes coming out of the heat pump outside are vibrating/shaking which then produces noise in the house.

Hi Cally,

There could be several causes of noise and vibration.

If you touch the outer casing of the ASHP, can you feel any vibration?

If you listen around the heat pump, in certain locations is the noise louder than in other locations?

How long are the external sections of pipe from the heat pump to where they enter your home? Is the pipework supported in anyway?

Has anyone tried varying the speed of the water pump internal to the ASHP?

Are there any external water pumps?

Has the system been bled to remove all the air?

@derek-m 

thank you for your questions - hope these answers help with ideas? 

yes the outer casing vibrates

we think the noise would be louder where the pump is

the pipework goes up about 2.3-2.5m and yes is supported

we have tried varying the speed, currently on lowest setting

no external water pumps

yes we have bled the radiators

@editor we think the pump (outside) is causing so much vibration that the noise runs along the pipes inside. the airing cupboard where the hot water cylinder is the noisiest; when the pump is on and also heating hot water and extremely noisy when in defrost mode - will be far too noisy to sleep (our bedroom is next door) if we have a cold spell.

we have only had the system for 2 weeks now so will be trying to get the installers out this week and also Grant out to see what the issue is but any ideas welcome! Grant said on the phone last week that the water pump should run silently so something must be amiss - just finding the cause to be able to fix it

Hi @cally-m 

Is the ASHP unit installed on anti-vibration mountings?

Because the pipework is connected to the ASHP unit, if the unit is vibrating then so will the pipework unless there is some form of flexible hose used.

If the whole ASHP unit is vibrating, then it may not be the water pump that is causing the vibration, it could be the compressor or even the fan.

I suggest that you ask Grant to come back with a vibration meter, and check the vibration level of all the internal components, to try to locate the source of the vibration.

@derek-m thank you - sounds very good advice! Will look into it more in the morning 

@editor apologies for the delay but here are some photos of the unit and associated pipework.

@cally-m, I received this comment from ASHP installer relating to your case: 

This issue is easily solved if it’s installed following Grants guidelines, the 13 and 17 kW Grant pumps have huge circulation pumps, when in hot water mode either a bypass or gate valve needs to be fitted on the cylinder coil to avoid this noise.