as per my PM but for the wider audience - I think FSV 5051 tells the system you will be sending it a value that (as I interpret that bit of the documentation) will attempt to control the compressor freq. with the means of sending that input value being either via modbus register 88 (I think… I only read the manual didn’t build it) , or via an analogue input (which I’ve no idea where it would connect) . If only setting FSV 5051 by itself , without also adding that input, I wouldn’t expect it to do anything.
if you want schedule space heating flow temperature target changes using only the samsung controller, then you will have to put your system in to fixed water temperature mode driven by the controller, not sure if that is what you want?
According to manual just enabling FSV 5051 and bringing 0v to green FR control connector should limit compressor frequency to 50%. I tried it but heating DHW cycle looked the same as before.
Yes, i would consider switching samsung controller to water temperature mode and driving it with some external room thermostat or with my own raspberry pi programmed logic.
Samsung controller as a room thermostat doesnt work for me. If i set it to 21,5C it starts heating and wont stop until 22,5C. After that the energy from floor is still being released and my small insulated house gets overheated to 23,5C, with sunny weather even more. WL is set to 32C flat.
Now i am running it in scheduled blocks of 3hours heating and 2hours not operating. If the temp is ok after first heating block those successive will usually not activate the pump at all.
So now i am just happily monitoring it and will wait with other experiments until spring hopefully
You can use the SmartThings integration to connect the Samsung WiFi to Home Assistant. However, the integration is very poor, only DHW on/off controls are available. I don’t really use it.
But I have some problem with this f*** pump. This happened now absolutely no idea what is going on here. The pump was off for 2 hours or so so finally temperature reached the lower limit and the pump started. Well great… But what happened ? It switched it off after 4 minutes!!! Water temperature was 20C in pipes… While it has switched it switched the pump off as well despite the fact I’ve set FSV 2093 to water pump 2 so it should not stop. I absolutely not understand this HP. Why it has switched off???
I’ve just noticed they’ve installed Grundfos 25-40 !!! Not 25-60 as I’ve thought… I think that’s why I have such poor flow rate. What do you think Ian? I don’t know why I thought it’s 25-60.
Now I’ve started it and I’ve got Error 911 for some reason. Do you have an idea what it could be ? What does it mean ? I don’t understand from manual.
Thanks.
UPDATE:
Guys tell me if I’m dreaming or what. So by accident I’ve found out that if you go to self-test settings to e.g. watch your LWT and RWT then guess what? The PUMP will shut down!!! (because it automatically set pump to OFF) So then I can wonder why the pump shuts down after a while! OMG. Who implemented this ? Once you go out from self test menu, it start working again but this means you can’t watch inlet and outlet temperatures! Well you can switch pump “ON” in self test menu but this will put your PWM pump on MAX. SPEED, resp. the last fixed value which has been set on the pump. So monitoring temperatures makes no sense. Jeeeeesus Christ, tell me this is not a truth.
Sorry guys, I know I’m a bit boring but I’m really out of ideas.
It seems that PWM regulation does not work a bit. Now the HP is able to turn off the pump off and on but seems that speed control does not work at all. If you look at these two pictures you can see that HP requested to lower the speed but pump completely ignores it. At 77% is bigger than it was at 93%. All circuits are fully open. Do you know if I need to setup besides just connecting the PWM cable from pump to HP ?
Seems now it decreased the speed but only if inverter pump was below 70% or so. Now it is at 58% and shows 13.9 l/s flow rate. Do you know how the pump determine maximum and minimum speed of the pump when it is only sending signals and not receive ? Don’t understand if HP does not have a terminal for output signal from the pump. I thought that it will somehow determine the max. flow when it is on 100% and then decrease to 0 where 0% is no flow of pump. If anyone can explain how this PWM works exactly I would be glad. Now it is at 54% showing 13.3l/s so seems it’s doing something. Dos it mean that 1% is minimum flow rate of the pump which is 7 l/s ?
Also another question. Now it’s 10C outside. The HP show energy efficiency 3/5 only and it runs on 800W right now. The output water temperature is 37.5C. Can someone explain why it show such low efficiency of 3/5 and not 4/5 ??? It is because my heat exchange is slow (because of small radiators) which are not able to expel the heat more quickly so the compressor needs to run on low RPM’s where it is not that sufficient ? If so, would it help to increase WLT to e.g. 45C even there is 10C outside so it can expel more heat? Will this be more efficient that running at lower flow temperatures ? I’ve checked stats for today and input energy is 30.5KW and output 9.1 which gives COP 3.4 only. According tech sheet it should deliver COP 4.4. Even for 50C water it gives much better COP@7C = 3.6. So make it sense to just set the temperature curve to almost linear ? e.g. 15C@45 and -15C@50. Does it makes sense to get better COP ?
thats actually good news. that means the system is running only about 3.2m head at the moment. So , if you get a normal 8m head pump (something 25-80) that should be able to get the flow rate you need. you need a curve with at least 6.1m head at 1.4m3/h (thats 24 l/min).
I completely ignore the efficiency number on the system status so I don’t know what mine usually says or the meaning of that number.
you were asking about home assistant monitoring : I have installed the modbus module in the outdoor unit, I connect a wifi ESP to the modbus cable , and then pull data via the ESP into home assistant. and then upload the data to emoncms.org which is where all the nice graphs we all keep showing you get generated. there is plenty of discussion about this , on this forum in other threads, and on renewable heating hub. Please read those first.
don’t worry about exactly what the PWM % number says. if its varying the flow rate, its working. you can alter the target DT which affects target flow rate but given the pump and emitter issues on your system I wouldn’t mess with that value yet.
At these low power levels, your system will have a minimum electrical power that it won’t run less than. Plenty of people have seen this , not just on these units. just ask @matt-drummer about his daikin!
You can turn down the WT and get less energy out, but you won’t be able to put less energy in, so once you are at that point your COP will keep getting worse if you keep lowering the WT. So you may as well keep the WT up a bit higher and have the energy. then your system should turn off on the room stat.
I would say if its stable at 800W , everyone seems to think that its got same engine room as the bigger units, then thats as low as you are going to get and you should be happy. FYI 800W is pretty much the low point on my 16kw unit. you just need to find a WT thats stable and that you’re comfortable with. more emitters will help!
Yeah, still lot to learn. I will deff look into it.
PWM works but seems it starts lower down only from 75% and below. Don’t know why. Do you know what is the control factor in pump settings ? I have set it to 2.
But now I guess the main problem is the weak water pump. They’ve installed 25-40 and not 25-60. So characteristic +/- match. 16L at 3.3m which is height of my radiators on the 2nd floor.
Much higher flow at that height. What do you think ? Not sure what exact issues this will solve but I know that the HP always asks for more flow when I start it since it shows 100% at 16 l/m. How much more I have no idea but could be easily over 20. That way it could heat more efficiently since it takes some time until water in the system gets to the temperature.
I also have this tiny radiator closed in a room where I don’t need to heat and that room is pretty cold. Do you think opening it full could help with stability of a system and despite more heat is wasted the system can get better COP at the end ?
please, its getting a little bit frustrating. I did say all these things before:
height of radiators is irrelevant.
you need about 6.1m pump head meaning at least an 80 pump will be required. I thought before you needed something like a 120 (because you said you have 60) but now that you said you have a 40, then the maths tells me an 80 is enough (as per previous message). 60 will not be enough, it only has 4.5m head at 24l/min, you can see it in the graph you copied above.
control factor is a PWM/DT tuning. don’t mess with PWM / DT tuning until the pump is sorted,
if you can get more flow and achieve the flow rate that your HP needs, 100% flow will be a larger litre/min number. system will startup faster, it will be able to achieve full power output.
yes in general you should open all radiators. If not done already, try to balance them using the lockshield valve as well, so that all are warm.
Hmm, but I still not understand why and how did you calculate I need 6.1m head ? Sorry but I’m pretty new and simply don’t understand. If I look at the pumps 25-40 and 25-60 I can see that 60 is twice stronger ? Or it’s 4m vs 6m height. If 25-40 gives me 16 l/m what would 25-60 give me ??? Still 25-60 is better than 25-40 or ? So how much 20 l/m will 25-60 gives me ??? Sorry for maybe stupid questions but price difference between 25-60 and 25-80 is huge. But anyway 25-80 should resolve the flow right ? Maybe I will buy something cheap then.
Problem is that I don’t know how much it needs ? At start it always ask for 100% but over time running it is decreasing. So after a while, maybe 30 or 60 minutes even 25-40 is enough. Problem is at start…
All lockshields on all radiators are already fully open so this 16 l/s is as much as I can get with current pump.
When Ian says “3.2 m head”, this means that the pump is providing a pressure equivalent to the pressure at the bottom of a column of still water 3.2 m high, or about 0.314 bar.
10 m head ≈ 1 bar
It has nothing to do with the height of the radiators, because the weight of the water in the “down” pipe is almost the same, but a fraction more than, the weight of the water in the “up” pipe. And the difference is because hot water is lighter than cold water.
I have done the maths for you. you can either accept my maths or try to do it yourself but you keep getting it wrong because you don’t understand it. pump curves are not easy things to understand, to be honest, so that’s ok. The information is in engineeringtoolbox. If you can’t understand that , that’s fine, in which case please trust my answer. If I’ve made a mistake in the maths , I’ve no doubt one of the other fine folk on here will pick it up.
TLDR: a 60 is pointless. you need an 80. yes, an 80 will cost more. yes , an 80 will give you the flow you need.
If ALL lockshields are fully open then radiators nearest the pump will be taking more flow and those furthest away less. you need to balance the radiators so that all radiators send their fair amount of heat into the house. This will not affect flow rate but it will improve output. There is a good thread somewhere on here about balancing, not going to repeat it.
The pump will always run at 100% at startup then it will slow down to whatever speed is needed to maintain the DT for the amount of heat required. 16L/min will deliver 5.6kW at DT5, if your pump is modulating lower than this it means that it’s delivering less heat, which is expected when it’s not very cold.
23L/min is required to deliver the full 8kW of heat at DT5, you will only need this in very cold weather and quite possibly you will never be able to have 8kW of heat at flow temperature you want since it sounds like your radiators are undersized. I think you need to go back to basics to do a room by room heat loss calculation to see if your radiators and pipework are correctly sized. Adjusting controller and pump settings will only go so far, if your heat pump is oversized compared to the emitters and pipework there’s not much you can do to improve efficiency until this is resolved.
I would recommend https://heatpunk.co.uk for calculating heat loss, this has Samsung heatpumps integrated into it.
Guys, I appreciate that you are trying to explain it to me and I highly appreciate but maybe I’m stupid enough to not understand it at the moment, because Ian said:
“thats actually good news. that means the system is running only about 3.2m head at the moment. So , if you get a normal 8m head pump (something 25-80) that should be able to get the flow rate you need.”
So we know that actually I have 3.2m head and 16 l/m max. flow with 25-40 pump. So this this this chart here 16.02 l/min @ H 3.15m
So Ian, what max. flow I could get if I use 25-60 ? Isn’t it 36 l/min at H=3.2 ??
So if you can answer this equation it would probably help me understand:
Pump 25 - 40 — max. flow 16l/min
Pump 25 - 60 ---- max. flow ??? l/min
Pump 25 - 80 ---- max. flow ??? l/min
Can someone answer this please ? Don’t get me wrong but how you can say what flow my system gives without knowing how much tubing I have, what’s the total height of the system, what is the amount of water in pipes, how many bands there are ? Can you tell this only from actual performance of my 25-40 pump ?
@glyn.hudson said, even my 25-40 would be sufficient until there is very cold outside. I guess at least -10C. So maybe 25-60 would put me somewhere until -15C - -20C?
thats wrong because to move 36 l/min the amount of head needed would be a lot more. Loss goes up with the square of flow rate.
If you know the current flow rate and the current pump, then yes , it is possible to work out a prediction for flow rate with a different pump. I explained this maths about 20 posts back. But I clearly can’t teach you how to do the maths because you’re not going off and doing the reading that is necessary that I suggested to back up the explanations on engineeringtoolbox.com . you just want people to give you numbers, and then argue with them when they do.
I don’t have the time to work out what it would be with a 60, that is wasting time.
if you are 100% sure you are running with a 40 now, then the maths says an 80 will get you the 24l/min target that you wanted to support 8kw. Correct, you might not need 8kw steady state because your house loss is not that high, but your heat pump can do it so why not have the capacity available. And it should improve startup behaviour.
at the limit of my available patience now I am afraid.
