@cally-m, have you contacted the installer and complained about the noise? Are the installers MCS-accredited?

@editor thank you, we believe this is fitted as have a new grant preplumbed cylinder with an automatic bypass valve. The noise is the vibration from the pump running.

The installers are coming back next week with a Grant engineer coming too so will be interesting to see what the issue is and how they resolve it. 

@editor yes to both, so hopefully will be resolved when they all come to look at the problem next week. Hopefully a simple fix but will see and let you know! Otherwise we are pleased with it so far! 

@cally-m, that's great. Please let us know what the installers discover and how they remedy the noise. Would be great to know.

Hi Cally

We’ve had a 13kW Grant installed about a month now, and it was really noisy to begin with. It came from the pipes, although the outdoor unit would also rattle.

Turned out the system had loads of air in it. The installers were in a hurry to finish up on Friday afternoon and probably didn’t let it settle long enough. The result was lots of vibration both inside and outside and ‘toilet flushing’ sounds when the system turned on. The radiators were also absolutely full of air.

Do you have any automatic air release valves? We have 6: they’re the brass things with the black top hat in this picture:

We have those two on the cylinder, another two in the loft where the ASHP pipes come in, and another two in the loft at the highest point on the heating circuit.

They will let the air out, but you also need to let water in to replace it. On our system we have a pressure gauge:

 It should be at about 1 bar as marked by the red line (I’ve slightly over pressured this here by filling it when the system is cold). I also have a filling loop:

You gently open one black tap then the other to allow more water into the loop, until the pressure reaches the required value.

After a week or so my installer came round and found the pressure low. Adding water a couple of times cleared the toilet flushing sounds: I’m still tracking down other noises (eg some radiator valves whistle) but it’s much improved. The outdoor unit is quieter although the fan motor is still making some noise, there seems to be a casing resonance at particular fan speeds. I’m still working on that one.

Hi Cally - apologies for replying to this late post.

I also have an Grant Aerona 13kw with exactly the issue you describe:

when the unit starts/ runs  - the units pump pump can be heard resonating through the pipes in the house ( and you can feel them vibrating- from the flexi pipes outside connecting the ashp outside to the inside pipes connecting to the CH).

They run accross a cavity wall and create a drum effect. 

We’re you able to solve the issue - Grant have been totally useless.

The ASHP is appx 5 years old and has been like this since we moved in 3 years ago!

hope you can help. 

@jimbo69 As a follow up to my post above, I solved the other cause of my noise. The installer fitted my system with a Honeywell Lyriq on-off controller, which it turned out was cycling the ASHP 6 times an hour. By analogy it was like trying to drive at 60mph by jamming your foot on the accelerator, waiting for the engine to rev up to redline, and then letting off completely, repeating this every few seconds.

A simple test for this is to set the thermostat to some high temperature like 30degC and the adjusting the room temperature via the lock shield valves on the radiators or flow valves on UFH. That may take a few days of tweaking to get right as you need to wait for the room to reach steady state for each adjustment. If that works, you may find the ASHP become quieter as it is allowed to throttle down to match the heating load, rather than constantly being cold started and stopped by the external controller.

 The unit actually has outputs which are able to control the valves and pump in a traditional UK heating system, and the wall unit can act as a room thermostat while allowing the ASHP unit to work properly. I’ve rewired my system to use these and disconnected the Honeywell controller. My system is much much quieter now: I can stand inside about 1m from the unit, with an open window, and it’s about as noisy as the fridge.

Hi thank you for taking the time to reply.

My heating system is all connected to UFH…and the noise issue is not the ashp noise outside  but the pipes inside vibrating ( almost like a blockage - the pipe work in literally vibrating). The noise is driving me nuts as it runs up a cupboard to another manifold secured to a cavity wall- all pipework is correctly sized.

I’ve now isolated the issue to the pipes from the grant ashp to the by pass valve …they vibrate! I have 1m flexi hose from ashp to copper pipework  which then enters at below dpc and into the manifold cupboard. 
I’m pretty convinced it’s the fact that there is  copper pipes in screed in this run and they probably haven’t been insulated / secured properly. 

I can’t think of anything else it could be. A plumber suggested it might be a blocked heat exchanger but not sure how I would find that out.

I plan to replace with plastic 28mm..

The scenerio Cally outlined at the start almost mirrors mine .

One thing I fixed was my dozy installer had screwed the copper pipes from the ASHP to the loft joists with regular brass pipe clips. (Flexi tails outside, copper up the wall, copper in the loft, copper to airing cupboard with cylinder). This meant vibration was being transferred through the ceiling. Before I fixed the controls this meant there was regular vibrating noise every time the unit revved up. I replaced the pipe clips with rubber lined ones which helped a bit. But the noise only really went away when I redid the controls.

Update - after numerous visits from Grant,  numerous plumbers & heating engineers, and the expense of changing pumps  etc chasing good money after bad - I bit the bit the bullet and changed the whole ashp pump - quiet as a mouse, can’t even hear the system when it’s on.

The cost of the new system was less then what I’ve spent on trying to remediate  the bad pump!!