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Grant Aerona3 13kW Noisy pipes after balancing

Grantmethestrength · 2025-02-16T09:03:11Z

Morning all, I spent most of yesterday balancing my rads most of which were fully open with a DT of about 1-2c, I have got them all to between 5-6c following @Toodles great guide however the system is now really noisy, you can hear the flow through the pipes. Not great as OA is now miffed at me as it is my tinkering that has cause it. I did point out that the house is much warmer as a result to which I got a “It is too hot!” Please help! Currently my settings are: 38C @ -1c full WC Pump speed is near constant 4400rpm Power consumption is pretty constant at 1,100w flow temp is 36c and return is 33c System is pretty much all new pipe work and new rads. I am away with work for the next few days, should I just open the rads up again to appease OA (happy wife=happy life)? Cheers Si

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Air Source Heat Pumps (ASHPs)

Last Post by AllyFish 2 years ago

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AllyFish

(@allyfish)

Prominent Member Contributor

Joined: 4 years ago

Posts: 520

19/02/2025 1:02 pm

Hi @grantmethestrength, looks like your pump setting is on speed 3 in your Grant ASHP, grab the installation manual, read up on circulator pump dip switch settings and drop it to speed 2, circa 3000rpm. You may have to open up some rad lockshields and recheck, but getting a pump speed appropriate to the required flow with a reasonably open circuit is preferable to the pump running flat out against closed valves. The Grant ASHPs are defaulted to speed 3 when supplied, and few installers bother to change that, because throttling the flow on the Grant supplied flow setter/indicator is the lazy, quicker and easier option.

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Grantmethestrength

(@grantmethestrength)

Reputable Member Member

Joined: 2 years ago

Posts: 185

Topic starter 19/02/2025 3:45 pm

Thanks guys, I will open up the valves again and check the dipper switches when I get home tomorrow. Quick follow up question, if the flow has been limited at the ahem new to me flow valve 😜 if I change the pump speed to 2 do I just open the flow valve up to get say 28l/min or just open it as wide as it can go (well until it gets noisy again lol)? Is there a sweet spot?

Kind Regards
Si
——————————————————————————
Grant Aerona3 13kW
13 x 435w + 13x 480w Solar Panels
Sigenergy 10kW Inverter
25kWh Sigenstor battery

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Toodles

(@toodles)

Famed Member Contributor

Joined: 4 years ago

Posts: 3052

19/02/2025 4:21 pm

@grantmethestrength The new to you flow valve is summat I know not of at this stage but, my gut feeling is that if it is in the water circuit, is partially closed and you have noise then, it is well worth noting its’ position then openi9ng it up fully to see what happens. If at this point, everything runs happily still but the noise hasn’t disappeared, then try the heat pump’s pump by reducing the speed a little. little by little improvements will come your way! Regards, Toodles.

Toodles, heats his home with cold draughts and cooks food with magnets.

👍

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AllyFish

(@allyfish)

Prominent Member Contributor

Joined: 4 years ago

Posts: 520

19/02/2025 5:57 pm

Posted by: @grantmethestrength

↑

if I change the pump speed to 2 do I just open the flow valve up to get say 28l/min or just open it as wide as it can go (well until it gets noisy again lol)? Is there a sweet spot?

Pretty much, noise is caused by high fluid velocity and turbulence created by restrictions, which is caused by things like nearly closed balance valves, TRVs, etc. Noise is also wasted energy, as is a pump on max speed against partly closed valves which could be on a lower speed setting. Open all the valves up, including the flow setter/indicator, set the primary circulator to an appropriate speed to get the required system velocity, and go from there 🙂

👍

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