You can use FSV 5051 yes, it’s the same. However, I don’t know if only setting 5051 sets any cap of the compressor frequency. I previously read that there’s only 2 options to cap the compressor once 5051 is set to enabled. It’s either through a 0-10V entry on the MIM board, or by setting the 42F1 modbus register.
Either it’s that there is an implicit cap value (I’ll confirm that), or that the weather condition changed…
Given my experiment and monitoring, quiet mode is somewhat a FRC, but it has adverse effect. Also FRC is enabled also for DHW cycles. On my setup (gen 7 r290 5kw), it takes longer to heat up the water tank, but it never consumes more than 1kw, and the CoP is much better, as it takes longer to reach the top water flow temperature compared to uncapped behavior.
Could any of you experiencing this ramping up and down of the compressor provide a log of the power consumed (if you measure that separately with a dedicated meter) over time or a log of compressor current?
I am having oscillation issues as well but on my heat pump the compressor makes total stops.
The frequency number keeps showing above zero values but compressor current drops to zero, measured power to about 7W and if you stand next to the unit you notice that also the fans stop.
I have an AE160RXYDGG
Sample Snet-2 Output below; note how the compressor stops even though the water outlet setpoint is well above the current water outlet temperature.
After some more time another few stops with 1 with the frequency above the minimum 15Hz.
The PLC is programmed to set the water outlet set temp to above the current outlet temp so basically there should have been no reasons to ramp down let alone stop the compressor.
Currently if I increase the offset between current and setpoint the frequency of stops increases.
Does anyone else also experience this behaviour? I notice this since october this year.
Lots of us have queried what the Snet field “Compressor Current” actually means, especially as Samsung assign the units “degC”. Maybe better to trend Outdoor Unit power consumption. I showed how to add a field for this value in Samsung ASHPs: Customising Your SNET-Pro2 Display . (If you want to set this up, be aware that some of the code in my post got slightly mangled by Discourse and I had to edit slightly it to make it printable - I don’t understand the ¬¬¬ convention at all - but you should be able to get the picture. Just save the original Snet files somewhere safe so you can revert if necessary.)
On my HP multiplying DC Voltage with compressor current is usually within 10% of the measured power with my 3 phase Modbus meter. So my best guess is that it is actually current and the temperature unit is sloppy programming by Samsung.
The dips to exactly 0 correspond exactly with the moments of compressor and fans stopping if you stand next to the unit observing while it happens.
The remaining few % I think I can attribute to power consumed by the fans but I have not managed to make time to check that.
I did set up a model of fan power as a function of rpm though.
It consists of a fit curve though a Samsung graph they use to illustrate the efficiency of the new DC fans compared to the old AC ones as a function of rpm and some basic fan physics.
Sarah thanks for the message you sent me privately I will check it out a.s.a.p. but that may not be soon.
My current 16kW heat pump is to be replaced Monday with a new 8kW one and I am also going to switch to Modbus control with the Samsung MIM-B19N instead of my current Intesis gateway.
I was just checking this and don’t understand this Samsung once again. So I have FSV #5051 where I can enable FRC. But there is only option to Enable or Disable. Why is there no option to set max. frequency in the same menu, e.g. #5052 ?? If I enable it what max. frequency (frequency ratio) is used ? From my observation it limits compressor speed at DHW heating to 30Hz and space heating to 22Hz… But how it corresponds to frequency ratio I have no idea.
But fine, this is good until around +5C outside but bellow I need to increase max. compressor speed to maybe 26Hz or 32Hz… But how for the god sake ??
Why the heck they say only tank-integrated hydro units ? WTF ? I have a Monoblock so how I can set frequency ratio ??
@SarahH you are my last hope, do you understand this ? Maybe you could drop email to Nick for me because I really don’t understand it.
Now the outside temps is around 0C and 22Hz is not enough. Yes, compressor is running nice and stable at 22Hz but heating power is not enough. It makes flow temp 41C max. and I would need 42-43C but because FRC it can’t modulate higher.
Here is my last run all nice and steady but input is too low and my target temp 23.5C can’t be reached.
That’s a great question and I have the same problem. Setting fsv 5051 to ‘use’ limits the compressor to 50%. This can be adjusted using modbus or by applying 0-10 volts according to the manual. 0 volts = 50%. But that’s where the explanation ends, which is of little benefit to most users. does anyone understand what the modbus code should be? I have a ESP32 device connected to F1 and F2 and can control certain functions thanks to some very clever people on GitHub. It would be great to add this functionality.
I was testing the behavior but honestly it works strange. I’ve set target flow to 45C and the pump was not able to achieve that even at 70% FRC. It limited compressor to 31Hz but it stayed there only for a while and then fell down to 22Hz again and never went up. Like it was with 50% FRC. So I don’t understand why because it was 3C below target flow. Also my water pump speed was at minimum level 9.6l/m and delta was 5C while I’ve set target dT=6C so I don’t understand why the HP didn’t increase the power to 25Hz or 27Hz and flow speed to reach the target flow temp. I will never understand this Samsung pump, never. It behaves irrationally or maybe I don’t understand it.
One important notice if anyone is controlling FRC through 0x42F1 - the set value is valid only for 1 hour, then it will reset to 0!
So if you want to use this to control max. compressor speed you need to write the desired value at least once per once on this address.
Another finding is you can increment number only by 10.
306 - 50%
316 - 60 %
326 - 70 %
…
406 - 150%
You got the point. If you try to setup up number which is not listed here it will revert back to the next nearer matching number. E.g. if you set 311 - it won’t be 55% but it will revert to 50% so it will store 306 at the register.
Anyway, on my system the compressor always starts to hunt if flow is near the target - e.g. I set 45C target flow and it starts to oscillate around 43.5C. This usually means that target temperature is hardly achieved because compressor start to bounce with frequency up and down. Very hard to stabilize especially in warmer temperatures. If found setting the weather curve flat to 55C and control the pump exclusively with FRC and thermostat makes it running much more stable. No more compressor jumps, everything stable. In normal circumstance target temperature is never reached. I have an automation which changes max. compressor speed based on outer temperature. Now I’m trying to run 50% FRC (22Hz) for +5C and above. 60% FRC (27Hz) 0 - 5C. 70% (32Hz) 0 - 5C. 80% -5C to -10C. 90% -10 - 15C and 100% below -15C. This keeps the house at 23C roughly. Not sure if this numbers will be good enough but I will observe and modify if needed. I can also follow indoor temp and make some compensation if it struggles to reach the target indoor temp.
