@jamespa s only what the room thermostat says when it moves from one of four periods , generally it doesnt always achieve this . TRV's completely open now according to new advice. Wow thats been 8 yrs set up wrongly!

Now the room thermostat is set for 24 and finally the Kitchen is at 22c. So I will look at other rooms now.

OK I get you now, you are using the scheduled programmable temperature feature on the Drayton.  This will switch thee heat pump on or off according to the programmed temperature and the measured temperature.

I will give some thought as to whether there is a neat way to make things work with Cosy, but a crude on/off function (which is what the Drayton does) is never a good start when it comes to heat pumps! 

TBH if I had a Samusng heat pump and wanted to do this sort of thing I would probably get a Homely.  However I dont, I have a Vaillant heat pump and a 'simple' 7hrs cheap tarrif at night, so just programming a nighttime 'set forward' (which the Vaillant controller can do) is the way forward.  I haven't bothered to do this as it happens but probably will when we get to the shoulder season.

I think your way forward is to keep TRVs open with balanced radiators, the programmer set to higher than you need 24x7 and the Water Law adjusted to get the temperature you want.  In other words get it working stably with the Water Law being the only control and turned down as low as possible.

Once you have this working stably you could possibly to overlay a timed switch off in the couple of hours before the cosy cheap rate (and during the Cosy expensive rate).  This will require you to jack the WL up a little, but hopefully not too much.

Can I just check that you are happy you know how to adjust the Water Law.  I think its FSVs 2011, 2012, and either 2031, 2032 or 2021, 2022 depending on the value of FSV 2041.  Is that what you have.  Your controller is older than the current one (which is the one for which I have the manual)

Thanks James , hopefully getting there. By the way its a Danfoss not a Drayton , probably similar though.

Yes its 2021 , so I will put down the WL 1 degree and see how the room temps fare. Its kind of what I have been doing but Room thermostat has been tight to the mark . I wll see how we go.

Thanks for coming back on this.  As you have probably gathered Im not a Samsung expert, just an amateur who has been studying this stuff for a couple of years in prep for my own heat pump, which I now have.   Anything I say is offered in good faith, but in the end its your decision.

Please don't do anything you aren't comfortable with and please make a note of settings you change just in case something needs to be set back.  The Samsung WL interface is, like many others, not a model of user friendliness, but you are on the right track adjusting 2021 while its cold.  It should be possible to get it so that the house gets to temp at more or less any OAT, with the TRVs off and thermostat well above desired temp, without having to continually adjust the WL, but that will take some tweaking over a period of time.

Another thing worth mentioning about TRVs is that, if they happen to be shut when the unit does a defrost, they can deprive the unit of the hot water it needs to do the defrost.  This is another good reason for setting them above the desired temperature.  Of course you may have a buffer or volumiser that provides water for defrost also, although the former have their problems to say the least!

I saw somewhere else on this forum that Samsung basically doesnt allow you to schedule setbacks etc, but there is a 'PV boost function' that is adjustable and can be triggered by an external switch.  This raises the FT by an adjustable amount while the switch is closed.  You could potentially use the Danfoss timer to operate this during cheap rate periods, which is after all what you basically want (to force it to work harder during the cheap periods, so it can slow up during the expensive periods.  I will try to find the thread and maybe make a connection in case someone else has already tried this.

Whatever you do Im pretty certain that starting from a position where the water law is basically optimised and the radiators balanced should be better.  Really installers should do this but it takes time, time is money, so they opt for something that is quick but not as good.  To overcome this the industry basically needs automatic radiator balancing and automatic water law optimisation both of which are beginning to emerge but not yet ready for prime time.

Please keep posting!

Yes there is a buffer tank , I ve been reading about them as not being essential , but will leave that for the moment . 
What do you mean by when you say that Samsung doesn’t allow scheduled setbacks please.  PV’s being a Pressure Valve boost function. 
Flow setting is 43c at the moment and large rooms still very warm . I will leave till tomorrow. My conservatory is next to lounge and very cold with minimum opening on both rads in there , lounge a bit colder as a result, 1.3 degrees less than next room with door open . easy sorted with wood burner. 

Its becoming clear (and installers are beginning to come clean on the matter) that buffer tanks are unnecessary in 95%+ of domestic situations.  They come with a performance penalty of up to 15% or thereabouts, and make fault diagnosis difficult.  Historically they have been fitted to prevent problems which otherwise cause call outs, but really they are masking them not preventing them.  The more enlightened installers now admit this, but many are still clinging to the old ways.  When @editor did a video on buffer tanks (on this site) he managed to find three installers who would join to advocate against buffer tanks but none of those he invited who advocate for would take part.  That says it all!

2By buffer tank I mean a 3 or more usually 4 port tank (flow and return from heat pump, flow and return to heating system).  2 port volumisers are useful and have no performance penalty.  These are fitted in series in either the flow or the return (arguments for both) not between flow and return. Turning a 4 port buffer tank into a 2 port volumiser is something worth considering. 

Re  "What do you mean by when you say that Samsung doesn’t allow scheduled setbacks please.  PV’s being a Pressure Valve boost function. "

The Samsung controller does have a built in scheduling function, but it only triggers on/off operation of the heat pump using its internal temperature sensor (basically it does the same as your Danfoss but using its inbuilt sensor and timer function).  What you really want is a function which, rather than switching the heat pump on and off, turns the flow temperature up or down according to the a schedule (to follow Cosy or for night time set back).  Some heat pumps (Vaillant, Daikin, strangely not Mitsubishi) support this, others don't.  Samsung doesn't.

PV in this case is photovoltaic - solar cells.  The Samsung function boosts the flow temperature by an adjustable amount if a contact on the control board is closed.  They call it a PV function, I suppose their idea is that if you have free electricity from PV you bump up the FT to take advantage.  Yours is a relatively old model so might not have it, but if it does its a way that what you really want to take advantage of Cosy could potentially be achieved.  

Re your lounge and conservatory obviously I dont know what you want to achieve but you know how to adjust the lockshields so you know what can be done.  There is a limit to how much temperature difference you can get between two adjacent rooms and, counterintuitively, it is usually increases costs to leave rooms unheated (explanation and worked example on Heat geek site).

Keep going until you have the Water Law curve as low as it will go consistent with your house being warm enough.  Thats the optimum efficiency point and the best starting point by far for any tweaks.

Hope that helps, I will post my thoughts on your 'Cosy' problem in a day or two. 

@alfapat

I hope you are getting closer to the optimum adjustments.

Ive given some thought to how you can operate the optimised system with Cosy.  I think there are 3 options, all starting from the situation where you have stable operation at your desired temperature on water law only as low as it can be (I will refer to this as 'optimum'), with no external controls operative

1. Adjust the Water Law to a degree or so above the 'optimum'.  Then use the Danfoss more or less as you were previously, setting it to a bit higher than you want during the cheap periods and the temp you want during the expensive periods.  Leave LSVs open

2. use the Danfoss to turn the heating off during all or part of the very expensive period, and the periods just after the cheap period.  Adjust the Water Law up as necessary to get an acceptable temp (should need only a degree or so above the 'optimum' - a bit like the previous)

3. If your heat pump supports it, use the Danfoss or an external timer to set the PV Boost function during the cheap periods and just before the very expensive period.  Turn off the heat pump during all or part of the the very expensive period and for an hour or so after the cheap period (you could use a second channel on the Danfoss or the heat pumps own scheduler to do this).  

I think (3) is probably the best but depends on your heat pump supporting the PV boost function and its also definitely the most complex although at the same time in a way the 'cleanest'.  If you can and do decide to choose 3 I have some thoughts on how you might decide how many degrees to boost by and how long you should turn off by, basically using the 'degree minute' concept that at least two models of heat pump use as part of their control loop. 

Im happy to contribute further on this if you want, its interesting to me to think about this problem as I have yet to program my heat pump to take advantage of the tarrif I have (EON Next Drive, essentially a variant on economy 7, giving me 7 hrs at 7p/unit overnight in return for ~10% uplift on the daytime rate- Great for charging an EV, averages out at less than the standard rate for a 'constant load' like a HP so overall not bad if you have an EV)

Morning James , Iam at 42c and just changed to 41c . The overall temperatures in the house are managing so far with the thermostat 2 degrees at every stage above the the normal 21/22c . The power usage is more levelled on the smart meter but has risen in the last 3 days of this adjustment . . So will see , it is -4c this morning but not seeing that graph till tomorrow. 

I will think about your options but very unsre if they will work , especially the PV ONE Aas I dont have photovoltaic . I m sure that was your explanation of that abbreviation. 

Ill work on getting WL down first.

Posted by: @alfapat

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I will think about your options but very unsre if they will work , especially the PV ONE Aas I dont have photovoltaic . I m sure that was your explanation of that abbreviation. 

You dont need actually need to have solar panels (photovoltaic) to use this option, you are just using a function of the Samsung (if yours has it) called photovoltaic, which in fact is just a contact that you can close to boost the flow temperature.  I think this option, if it available to you, has the best chance of working, but is undoubtedly the most complex.

The bottom line here is that the heat pump controller, like most, is not designed for 'tariff optimisation', so whatever you do is a bit of a kludge.  The only controller I know that is designed for tariff optimisation is Homely

There is actually another option for tariff optimisation - Havenwise.  They now apparently support Samsung - take a look at their website.  You need an internet interface to your heat pump but then its a service in the cloud (as is Homley at least in part).

Update.

So far on Wl settings for the last 24 hrs  is at 41c. 

I get it that looking at the smart meter recordings  shouldnt be taken as read. The average temps in my area in the last 14 days have been around 5c duribg the day and 2c  at night last three a little lower with frost . This could be an indication why my energy usage is still a little high despite dropping down WL  from 45C to 41c . I can only relate this to HP adjusting things in order to give the same house temperatures . 

The most recent night (morning of 23rd Jan) it was down to -5c outside so the total for 23rd was 79kw the 22nd which had WL SET at 42c the energy used was 82kw. I cant work out what is happening yet so I will leave at 41c

Foot note for the 17th Jan I only used 38kw and looking at temperatures for that day they were much the same 5c and 2c at night . WL was 44 or 45c around these dates ?

Head Banging!

Posted by: @alfapat

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Foot note for the 17th Jan I only used 38kw and looking at temperatures for that day they were much the same 5c and 2c at night . WL was 44 or 45c around these dates ?

Head Banging!

Which is why I ignore individual daily readings completely and plot daily consumption Vs average oat over a period of weeks at least.  The scatter on this is sufficient (at least in my case) to prove that looking at individual days is fruitless, and the only real approach that can be taken requires monitoring over several weeks to months.

The underlying problem, I think, is that houses have memory of 24 hours or more, so two identical days are in fact very different if the preceeding day or two was different.  Also wind and solar gain matter.

How you deal with this is up to you if course.

Thanks James , just trying to get assurance thats all ,and trying my best within my capabilities.

I will stay static for a whille now.

Cheers!