Samsung Gen 6 8kW Efficiency

Hardware Heatpump
161

Thanks for calming down :slight_smile: It is creazy becaue when there was freezing yesterday I had oposite problem. My flow rate was too low and it was also cycling. Now it’s seems to be oposite. So before, I’ve removed all TRVs and opened all radiators to full. This gave me 16l/s of flow at at 0C there wasn’t singe cycle since! For 12h no start/stop cycle. But it was warm and it has started to cycle again. So I don’t know how to tune it so it’s good also at these freezing temps an also at warm temps.

So this can modulate only to 50% of max. power ? Isn’t it too low ? :-/

But why it switch off if TW1 and TW2 are OK at dT = 5 difference ? Why it does switch off, how does it know to switch ??

This is interesting what you have said “f your roomstat sends “room temp nearly satisfied” signals to the MIM more than than ~3 times per hour the MIM controller algorithm starts cycling the ASHP, Set the roomstat to <= 4 pulses/hr to the MIM.”

What do you mean by this ? I have this controller in my living room and is connected to MIM. What does it send exactly ?? This is confusing because I didn’t set desired temperature at all! So how does it know if it satisfied or not. Very appreciated to explain this.

UPDATE:

So your pump is driven by this thermostat where you set desired temperature ??? Probably that’s why it works for you!

This was exactly I was thinking, to have stupid thermostat which sends the impulse to pump to turn if temp decreases by 0.5C.

But with that controller unit you can’t do that. It has temperature sensor but seems to me it’s useless and it’s only to visualize the room temperature.

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Even though my radiators are big enough I find that I turn the flow temperature down as it gets cooler.

I just try to keep the electricity consumption at its minimum.

This is because my heat pump is grossly oversized and I never need more than its minimum output.

You need to turn down your flow rate, I am sure that you can do this on the pump, you don’t need pwm to do this?

Then turn up the flow temperature until you get your dT of 5c

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got it. I thought you were talking about some secret setting on the samsung side!

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one more time please Michal:

please photo your controller so we can see what mode you are running in.
and do you have any 3rd party controller or thermostat.

the things you are saying aren’t quite consistent so lets work through it.

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Hi Michal,

At a mean flow temperature of 32.5c through your radiators (that is flow of 35c and return of 30c) and a room temperature of 22c you need a total radiator capacity of around 33kW (at dT 50c) to absorb the 4kW of heat that the heat pump wants to deliver.

What radiators do you have?

Do you know the total output at dt 50c?

That is how they are normally sold, in the UK anyway, assuming a mean flow temperature of 70c and a room temperature of 20c.

166

Michal,
Unlike some systems (e.g. Daikin) Samsung do not offer direct deltaT (Tw2 - Tw1) control as far as I know. Your compressor speed is controlled by some opaque algorithm in the MIM controller based on the LWT, Water Law setpoint, and roomstat setpoint.
The “conversation” between roomstat and MIM is also important, and maybe relevant in your case (as it was in mine - see above).
Sarah

167

Hi Sarah,

Although Michal won’t be able to set a dT like I can he can do something I can’t and that is control his flow rate.

By lowering the flow rate to the minimum the heat pump needs and then setting an appropriate flow temperature he should be able to manufacture a DT of his choosing?

Then he can play with flow rate and flow temperature to his hearts content until he finds something that works.

All this is governed by his heat pump and radiator outputs.

To make his heat pump run without cycling he just needs to get his radiators to deliver 4kW of heat.

Heat produced is a product of the difference between flow and return temperatures and flow rate so it should be easily possible to manufacture the right conditions.

All we need to know is the approximate radiator capacity Michal has in his house.

168

Hi Matt,
It all depends on which circulating pump Michal’s installed (mine has 3 selectable speed settings but Michal’s may not).
I think that there’s scope on this discussion group for a learned article (John T.?, Glyn?, Tim?, Ian?) on the importance of controlling AHSP and emitter deltaT, and (my hobbyhorse) the importance of distinguishing daily power consumption (hence cost) versus instantaneous CoP. (There’s an argument that a 2.5 CoP for 14h/day is better than a CoP of 4.0 for 24h/day.)
Glad to see you still contributing positively given your own ASHP problems…
Sarah

169

Sorry guys I couldn’t reply sooner since I’ve reached number of comments for novice :slight_smile:

I’ve increased my temp curve a little bit so instead of target 38C water I have now 40C. I changed some other parameters in controller, not sure if properly lol. Now it worked for 25 minutes but stopped again. The next run is still running so now it’s more like 2 start/stop cycles in hour which is much much better.

Do you think 2 start/stop cycles in an hour is OK for the pump or is a problem? I don’t know how many start/stop cycles is problematic.

But now I guess it’s pretty clear. Simply the mump delivers too much hear for current heat losses at 5C which are around 3KW. So there is 1KW which is redundant so it’s obvious mump can’t work continuously.

But now my question… Why those stop cycle is always that short - 3:30 minutes. Why ? Why the pump can use longer cycles and then hear longer. I just can’t get this logic. In 3:30 minutes is not possible that the water is cold enough to handle the next cycle for longer.

I would be fine if it stops for 20 or 30 minutes when there is 5C outside. In such time the temperature does not drop much and could prevent this short cycling. Do you think if I connect it to external thermostat which simply turn off and on the unit once the temperature drop offset is +/-0.5 degree ? E.g. I have set 22.5C. So once it reach 22.5 it stop the pump. And then start it again once it reach 22C.

An old easy method. At that time the water would be pretty cold already so even the efficiency could be better until it reaches dT. Or am I missing something here ??? What do you think ?

I have home assistant so I could buy a temperature sensor and program it according to my needs. This would be enabled only when outside temp is 5+ degrees. Bellow I would let HP to manage it. Is this a good idea what do you think ?

Here I have one question for those who knows, maybe @SarahH. Do you have an idea why I have here displayed tank temperature 40C and ambient temp 20C ??? I don’t know why because I don’t have a tank and my room temperature showed in controler is 23C.

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And another question, if you look at this graph, do you know why that power lines are so hars for the inverter ? There is a difference of 150W so if we multimple x 3 it means it jumps from 1.0KW to 1.35KW every minute! Why ? When it starts it’s linear. Also my AC units have linear curve and not these pumpkins :slight_smile:

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Not sure what is inconsistent but here you go and thanks for your patience.

I don’t have any external thermostat yet. Check my previous comment with my idea to install one and use when there is warmer outside. Only MMC with wired controller from Samsung. No tank, nothing.

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171

Hi Sarah,

I never knew heating could be so interesting! I find heat pumps fascinating at the moment but I am sure it will wear off.

My own problems will soon be resolved as I am changing heat pumps, I have got as far as I can with this one and I have had enough.

Yes, two forms of efficiency, COP and electricity consumption.

COP is a deceiving concept that many of us fall foul of, it’s not the be all and end all.

But using the least amount of electricity to deliver just the amount of heat our homes is, so the holy grail is the least electricity consumption at the highest COP.

There will always be compromises to be made somewhere, and that is the fascination.

Getting our heads around the fact that we have a varying amount of heat available from a unit of energy depending on what we do, it’s the part that I find fascinating after all these years of burning stuff to keep warm.

It is also very interesting how much the brand of heat pump we have influences how we think, it certainly does for me. One of the best things about the Daikin is how much can be changed, I get the impression that some other brands are far less adjustable.

172

Michal, can you turn your flow rate down?

If you can, give it a go, I think your problem will vanish, although a new one will appear!

I don’t know what the minimum flow rate required is for your heat pump but get it is close to that as possible.

The adjust the flow temperature until the heat pump is stable, in equilibrium, that is where the flow and return temperatures are steady.

Remove any other influences, just run a fixed lwt if that is possible.

Then you will know where you are at, what is required to keep the heat pump running at a steady output.

Then you can start adjusting and automating things as necessary.

Trying to automate a heat pump that isn’t happy is impossible, you have to get it stable first, then you have a base setup to work from.

This is my approach.

And just to be honest, a big thanks to @ColinS for showing me how to do it.

173

thats odd, I didn’t see the screen looking like that before, unless with an external thermostat. so I think nothing is being your thermostat. that won’t help!

service mode-> Indoor zone option-> standard temperature → indoor

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totally agree. some systems I’ve seen publicised with enormous headline SCOPs (6), I suspect they do so by running all day even when its +15C . when most of us would just go for “off”. they may well have done a good job but claiming that is pointless.

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Now I think mine is as well although I can have 7KW looses in -15C. Crazy.

Yes I can do there are 3 levels, minimum is around 7 which is bad because 7 is minimum for HP. Then middle is around 10 and max is 16 lpm. I think for my radiators 16 lmp will be enough even in cold climate.

I just did it check my post. It helped a bit, but outside temp dropped to 4C now.

My problem is that it seems the HP shut down sooner before dt=5C is achieved. Don’t know why but I have to observe.

I have 10x T2 radiators (5x downstairs - 2 living room, 1 work room, 1 kitched, 1 hall, 1 ladder in bathroom. Then 5x upstairs - 1 hall, 1 bedroom, 1 wardrobe, 1 kidsroom 1, 1 kidsroom 2 and ladder in a bathrom)

I understand that pump produces more heat. I thought the minimum output power is around 2KW and not 4KW - knowing this I won’t buy it. Unfortunately it was not stated anywhere. Before I had 2 AC units Toshiba and they were running from 300W and those were 10KW together. It’s a shame this 8KW Samsung is only a software crimpled version of 12KW/14KW units.

What I don’t understand why that stop cycle is always 3:30 minutes. Jees, why not 15 minutes e.g. ? Would solve lot of issues.

I have no idea of total output unfortunately but all open they can deliver 4KW roughly to maintain 22C at 0C.

It must be really stupid. But what data do you think the roomstat send to unit ? I can imagine the only relevant value here is the room temperature but not sure what benefit this has. I still can’t set target room temperature anywhere. It simply heats unlimited until dT is exceeded.

Flowrate can be controlled manually on pump itself but Samsung MMC support PWM so it can control the pump itself! Cable is still missing, it will be here tomorrow so I will install it. But have no big hopes it will make a difference.

As I said, I had it at minimum before and it was also cycling for some reason where there were cold outside. Don’t understand but it was like that. Then I’ve maximized the flow and it worked fine in cold weather. So I’m idiot from this.

Well yes, but this is a problem when there will be 10C or more. I will have tropes here lol. Not sure a good solution. I just need that in case there is 5C and above that stupid pump stop for more than 3:30 minutes lol. 20 minutes I’m fine but how to tell her lol :slight_smile:

I have Sarah. I have Grundfos Alpha 1L 25-60 with PWM regulation. But those experts who installed it did not connect the PWM cable so it’s a dummy pump with 3 levels of speed I can set manually. But this will change tomorrow. It could be that this PWM regulation will do a miracle but I don’t know ? I know that when I connect this PWM cable the hetpump will be able to regulate the flow from 7l/m up to 16 l/m according its needs.

What pump do you want to install now ? I would make sure it can get as low as possible!

It’s definitely fascinating but frustrating at the same time. Electric boiler is far the most comfortable device in the world. It’s pity it has such a bad efficiency :slight_smile: What is more frustrating are these contractors companies. Completely useless. Only take money and they don’t care. How many people use their heatpumps like shit ? 80% ? Nobody care if it cycles, people even don’t know what is it. If I wouldn’t look at my electricity graphs I would probably never spot it.

It’s 7l/m. No worries, check my comment before this. It help a bit but it still not at lowest setting. Tomorrow I will connect PWM so HP will regulate and can go as low as possible :wink: Cross your fingers.

Also many thanks for your advices, also @Ian_Calderbank and @SarahH. Much appreciated

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Hey @Ian_Calderbank !

I’ve just checked and this was set to “Water outlet”. I switched to indoor and immediately got and error code E121. Short or open circuit error of the room temperature sensor of the zone 1 indoor unit (detected only when the room thermostat is used). HELP!

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I think it should clear if you off/on the controller.
there might be an FSV you need to change as well but I don’t have time to check it now sorry…stuff to do… possibly you need 2091=off.

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If your house takes 4kW of heat at 0c outside then it won’t take 4kw at 10c outside, the heat loss is higher at 0c outside than 10c, that is why your heat pump shuts down.

It starts again quickly because it is still programmed to be on, you asked it to heat and it only stopped as there was nowhere for the heat to go.

If your heat pump can take 7lpm then run it at that, the radiators will be happier and the heat pump will run for longer. You can probably run a lower flow temperature even at 4c outside.

The only issue will be that the house gets hot when the heat loss is less than 4kW

My heat pump is being swapped by the installer, they misscalculated my heat loss, it’s 4kW at design and they think it’s 7.6kW

The installer is decent and will swap it free of charge for a unit that will work here in my house.

Despite any criticism I had of my installer they are a decent company that have listened to my issues and offered to fix it. They have some issues but in most respects they are very good.

You seem to have quite a range of outside temperatures.

Once you get the initial problems sorted, even if you don’t always get the best COP it will always be significantly better than an electric boiler.

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Apart from not burning stuff anymore my main reason for wanting a heat pump was so that I could put in the heat my house requires constantly.

I always hated the gas boiler way of big dollops of heat and then nothing, I much prefer a constant house temperature that doesn’t fluctuate much.

For me, constant running, low and slow is my goal.

It’s efficient and comfortable.

I am a net annual exporter of electricity, I see nothing to be frowned upon by using some of it to keep my house comfortably warm 24 hours a day.

180

Yes, it really worked. Thanks. Will try to run it in this mode and observe the behavior. Only to know how exactly it works in this mode but I guess it will cycle much less since there could be maybe 0.5 hysteresis set ?

Just sow it has stopped again… This is killing me so even when driven by indoor temperature it is turning off? Well now it didn’t start after 3:30 minutes but 4:30. What I progress damn it. How to make this thing to follow the thermostat. What idiot programmed this unit. It stopped at 23C and then 4 minutes later while still 23C it started. I really can’t get it please explain me.

I guess I won’t be able to run this as I want without external thermostat which send the signal to turn the damned unit OFF. And after a set hysteresis it will start it again. I can’t see any other option or is there any? Simply 4KW is much when there is 5C outside so I need to stop it for longer to prevent cycling. Any piping modification or other stuff won’t help here. It produces more heat that my house need. I hoped that switching to indoor control help lot but seems it’s not… Maybe increasing the curve to 45/40 @ 5C will do that trick ? I’m out of ideas…

Yes, exactly. This is the problem I’m afraid and not a flow or pipework. Knowing minimal output of this shit is 4KW I would never buy and I’m afraid at 10C the min output is 5KW. Therefore I was searching for minimal power input of compressor but I did not find it. Maybe it helps someone else if the read this.

With PWM the pump can reduce flow to 7 l/m and probably it will run longer but how much longer it’s a question. The heat builds quickly at such high temperatures so it might not run for long. At lower temps I believe it will run without issues so it will regulates the flow as needed.

Ah I thought you have this Daikin for much longer time. Good you have good installers. Well temperatures here are probably similar to UK. In Jan we have average of 2C, February 6C. It got warmer, it was never like this but past decade is getting worse.