@iancalderbank here are the pipes at the rear of the heat pump heading into the garage

Hi - two things I've found reduced the 'flow noise' I was getting, might help you too:

1. Check for trapped air in your system i.e. bleed rads, and any other point you might have a air vent which isn't automatic (I had a lot of air in my LLH which has a manual air vent).

2. Try a different running mode for your Grundfos pumps. Grundfos suggest 'Constant Pressure' (CP) mode as an alternative to Constant Speed (CS)  - which is the default setting of CS3. I've found CP2 is about the same flow rate for me (although consult their manuals to see the flow profiles). Instructions on changing this are in their manuals, but it's roughly "press and hold the pump button when it's running, until the lights start to flash" and do the opposite to switch back. Avoid Proportional Pressure mode though (which is 4th light flashing; you want 5th light flashing)

@mikefl that sounds interesting thanks Mike I’ll have a read of the book and see.

@mikefl

  I have “constant curve” which is where it’s set for me currently, should I assume that’s the same as “constant speed”?

Managed to change to “proportionate pressure” which really did quite the system on setting 1. Obviously I’ve a little nervous changing it without the technical knowledge of the impact on the heating system…..before I contact the installer - who I’m not convinced will know - would anyone on here be able to settle my fears?

@dannymoss23 Yes - Constant Curve is Constant Speed (constant speed is a poor name, but you can see why it is that). Proportional Pressure is NOT recommended if your system has an auto bypass valve, which I'm assuming you have(?) Single presses of the button should get you to Constant Pressure which is what you should try. Make sure both pumps are set the same, and you must ensure you are still getting sufficient flow. If in doubt it's easy to revert to Constant Curve, which is why I suggested it as a 'quick fix' to try out.

@dannymoss23 so they've used the proper method as far as I can tell to get out  the garage wall to the ASHP (big hole, insulation through hole, pipe through insulation. They need to be encouraged to do the same to get the pipes the bedroom.

the devices outside with the gaps in insulation are anti-freeze valves. they are not done correctly, they should not have as much exposed to the air as they have. primary pro is your bible yet again (its not exciting but it really is worth looking at)

you should also check if they are sheltered from precipitation or drips from other parts of the house. Basically if ice or snow should form or sit on top of them , they will open (acting as though the system has frozen up) and start draining down that part of your system. They are there as a last-resort only so they need to be protected from weather.

air in system - yes a very good point. 

Do you have an air separator in your system? This is NOT the same thing as an air vent. An air vent removes large chunks of air (air locks) which can form at the top of any pipe. All radiators have them of course. All systems have to have air vents at all the high points, and they are cheap (£5).

Whereas an air separator removes tiny bubbles , which will never be removed by air vents. They are absolutely wonderful at removing flow noise. I have always had them on my systems.  Google "spirotech spirovent". They are a bit more expensive (order of £100-150 depending on size) but you only need one.

Ah yes sorry Mike got my pressure modes mixed up! Thanks 

@iancalderbank Where would I look for an air vent on the system and I’ll have a look?

@dannymoss23 PP will just be running slower, thats why its gone quieter.  check your flow rate, it may be lower than you want.

@dannymoss23 an air vent looks something like this

and will be at the top of any high points in the pipework . definitely should be one around your cylinder.

an air separator looks like this

 and you may not have one. but worth getting one fitted, especially if they are coming back and draining down.

@iancalderbank Hazaar! We have one……