I have a Samsung EHS Monoblock 12 kW system (model AE120BXYDGG/EU) with a Grundfos UPMM 25-95 130 (PWM-controlled) circulation pump and a 200 L buffer tank.
I’m experiencing humming and vibration noise inside the buffer tank whenever the compressor starts and the circulation pump begins to run.
The noise disappears when the compressor stops.
Here’s what has already been checked or done:
The system has been fully vented (no air found, only water/antifreeze mixture).
Quiet Mode tested – it reduces fan/compressor noise but not the pump noise. Also electricity usage increased instead.
Confirmed that the noise comes specifically from the buffer tank area during compressor and pump operation.
Tried partially closing the valve (balance valve) before the buffer tank to reduce water flow – this slightly changed the sound but did not eliminate the humming.
Verified that the pump speed cannot be adjusted manually, as it is controlled by the Samsung unit via PWM.
I have tried different modes (Auto, Heat). Issue rather starts when outside is less then 10 C degrees
It was even more noisy in Summer with +25C, but then technician cleaned up mud filter and situation improved (water flow improved)
Technician reduced inverter pump from 100% to 70%
PWM Settings are not configurable in Control Display for regular users. Is it possible to change it? How?
Noise is quite annoying as one of bedroom is near technical room. I invested to “quiet” system, but this noise is annoying. Please advise.
It sounds like the flow rate is higher than needed. Samsung only have an option to reduce flow rate to 70% max.
Can you post a photo of your system? Is the buffer a volumiser 2-pipe or a full 4-pipe buffer. If it’s 4-pipe buffer, then you’ll have a secondary pump somewhere.
Thank you for the response. Waterflow is ~33 lpm, Added few photos and short example video of the noise (it is getting much worse if colder outside). Proton Drive
I have Ambista 200L-BU buffer tank, yes it has extra pump (the green colored Wilo pump). I have adjusted its “power” to level 1 already before - this reduced some noise, but did not solve the overall problem. Thanks.
I have closed the valve a bit more for testing, now shows ~19 lpm (water pump running, but not compressor). Noise usually comes when Compressor and Water pump are running. If only water pump then sound is acceptable.
Sound like a strange situation. Have the installers used flexi pipes to the outside unit to reduce the amount of vibration being passed inside? Is the outdoor unit wall mounted?
Outdoor unit is floor mounted, see the pic Proton Drive , not sure which pipes are used.
Update - Buffer tank valve is more than half closed. Water flow 25lpm when compressor running. I can hear more clear sound of incoming water, but still Whistling/annoying noise included. If i could somehow tune that PWM controlled waterpump speed for troubleshooting..
When the system has running have you tried turning unplugging the pump to see if the noice is still there (only for a few seconds). I would presume it would be.
This would tell you if the vibration was coming from the compressor or the water. But based on your pipework it sorta looks a bit undersized for 12kw? Plastic pipe with inserts, i wonder if its the sound of water going over them. 33lpm though narrow inserts could be loud
Thanks for the photos. Unless I’m mistaken It looks like the system has been plumbed in 28mm MLCP which has an internal diameter similar to 22mm copper. With 30L/min going through, it will result in high velocity and hence noise.
Partially shutting a valve is not a great solution, since this will cause the pump to work harder and could increase the noise due to the increased velocity through the partially closed value.
To deliver 12kW @ DT5 requires 34.5 L/min, but there’s a good chance your house doesn’t actually need 12kW. The Samsung primary pump should modulate the flow rate down when it’s running at lower power. Without monitoring, it’s hard to know what’s going on. See this example of a Samsung heat pump which modulates the flow rate down during a cycle, there’s a good chance your heat pump is not running for long enough for the flow rate to modulate down: https://heatpumpmonitor.org/dashboard?id=116&mode=power&start=1759979820&end=1760011620&flow=1
Thanks for the answer. No good way to separately unplug the water pump, it somehow connected to Samsung controller. At least I`m not aware of. In that case I need to switch electricity off for entire system
Thank you. Could be they sold too powerful system for my house. I have 240 m2 to heat if done in fully and my understanding was 12kw is up to 250m2, hence such choice. How to “decrease” the power from 12kW? Is it possible to tune the PWM settings for water pump so that it works with less power? Or should I replace Grundfos UPMM 25-95 130 (PWM-controlled) with something else where I have more power to control it? How to make it to run longer to “modulate down”? FYI I have also noted that Auto mode is more noisy than Heat mode during night. Or maybe I was just lucky (heat mode took more electricity as well). E.g set 30c for Heat and it seems to be more “stable”. I hear less compressor noise, seems compressor gets executed less compared to Auto mode, why? Auto mode gets noisy if outside is less than 10C. Currently testing Schedule - during night Heat mode with 30c and during daytime Auto mode. Thanks.
Btw how to implement monitoring for it and make such fancy graphs? What is required for it - any good how-tos?
Or right I had presumed the pump end would be on a removable plug like alot of them are these days
So your heat pump will have a min compressor speed/power consumption. I, Without looking it up fully I think you’re looking at a 900w compressor min consumption. Given a cop of 3 to 4, that’s 2700W to 3600W of heating.
What is the heat loss of your property?
Auto on the samsung controller is for deciding it its going todo heating or cooling right. It will auto toggle based on the params set in the controller. Personally, I actively determine if it’s Heating or cooling and never let the unit decide.
Do you have Water law(weather comp) setup on your controller.
I bought a 3rd party PWM controller to control my Grundfos pump when I was having PWM issues from the Samsung controller. I’m now using it permanently to set a fixed pump speed which I’m happier with than the Samsung PWM controls. You have to wire the primary pump to the secondary pump terminals in the controller so that it can switch it on and off by cutting power, rather than changing the PWM signal to 100% (zero speed).
Thank you for the answer. I have no idea what is the heat loss of my property. Property was just recently built and it is holding the heat pretty well. Yes, I do have water law setup, see the pics below. Not sure what should be the ideal setting for it. Any recommendations welcome. Water Law settings
@matahh
Yes indeed, PLEASE attach your pictures here. As it says in the FAQ, if they are somewhere else and get removed, most if not all value of this topic is lost for future readers. I have promoted you so you should be able to post your pictures now, even if you could not do this earlier.
I would recommend that before you play around too much you get a good understanding of your heating requirements. I would ordinarily recommend using Heatpunk to model your own house which will then give you a heatloss figure, but this is mainly designed for the UK housing stock. It is extremely customisable though, so you might make it work for you. All you need is a few hours of your time and a tape measure. You can go as far as putting in the emitters and it will give you recommend flow temperatures.
For my system, I initially had an issue with PWM not working on my controller so Samsung replaced this for me under warranty. Since it got replaced in January to around 1 month ago I was using PWM. Last month I fit FRVs to my radiators to that I’m able to accurately measure and set the flow rate to each radiator to deliver the exact amount of heat required for each room. This only really works optimally with a fixed pump speed though, changing the pump speed affects the balancing, hence the fixed speed. I’m now using the 3rd party PWM controller to get the minimum pump speed I can get away with while still delivering the required flow rate to each radiator (plus a little extra for good measure).
I used a USB adaptor to power it with 5V, then put the PWM wires from the pump into it.
Inside the controller (make sure you power off before doing anything) the primary pump is usually wired up to B1 and B6 which is a permanent live. The secondary pump is usually wired up to B7 & B8 which is a switched live, it switches on when required. So when using a seperate PWM controller, you need to use B7 & B8. (Centre of the image below)
Update - I have enabled heating on multiple other room thermostats and surprisly pump is quite quiet. Buffer tank valve is also completely opened. 1 day before I set it to “Heat” mode with 30c and today enabled heating on 4 more rooms. From Indoor Zone Status Information I see water flow is much smaller than 34lpm and inverter pump working on less than 70% - seems something started regulating it? Note I have set inverted pump MAX to 70% already months ago. I see that compressor and water pump is working, but no annoying noise. One more important environmental change - since 1-2 days ago it is much colder outside (5C), before it was flapping between 13-7C. Any logical explanation for the rookie? Not sure if 30c and Heat mode is ok for such situation. Attached screenshots:
