Posted by: @jamespa

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If you wish to proceed without WC then please note the inevitable increase in cost. 

Please see my previous post - Ian will always be using weather compensation, whichever thermostat he chooses, so don't despair!

Posted by: @mike-h

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Posted by: @iantelescope

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The internal Thermistor , without  a timer, probably without offset , compensation or Hysteresis settings  is surely the poorer option?

Would the removal of the Weather compensation Control and Display ,help or hinder?

There has sometimes been some confusion over what is controlling the Samsung heat pump behind the different displays on the wired remote controller. The attached pdf may help to clarify some of this. If the internal thermistor is used, then weather compensation will be active and controlling the heat pump whenever the thermostat calls for heat. There are extensive timings available within the controller should the user wish to switch the heat pump off at a lower indoor temperature at night for example. The hysteresis is roughly 1degC which may not suit all users, but I have found it comfortable and useful. I need to do further testing, but my feeling is that short cycling when it is milder is less of a problem when using the Samsung thermostat compared with the use of an external thermostat.

The main disadvantage for Ian is that he likes being able to use the Offset control and that option isn't available when using the 'Set Indoor Temperature Display Option' (see attached). But I must stress that weather compensation is active whichever of these two options is selected.

-- Attachment is not available --

 

Thats very helpful thanks as

a) it confirms the key thing that I had inferred from others, namely that it is possible to use WC and the internal temperature sensor in tandem (which solves a problem Ian has with his external thermostat)

b) it also confirms the fsv 2092/2091 settings for this and the Temperature display option.  

c) I had the impression it was possible to disable WC but it appears not, which is good!

FSV2093 is still a bit of a mystery.  If using both internal temp sensor and WC I have the impression the default value (4) is the one to choose as this sniffs the LWT from time to time and thus gives the unit the information it needs to decide whether to turn back on because LWT is low.  But I cant actually work out what the other options are for.  Do you have any insight into this? 

@mike-h & @jamespa

"This only works when an external thermostat is in use." reference Water LAW

Many many thanks mike ,

I was concerned that my Weather compensation may not have been working without a Water Compensation Screen being displayed!

I have used the Water Compensation ,aka Water Law screen for two years, because I can see, and control,  the  Water Law !.

Your  pdf on Samsung Screens says that the Water Law screen only only appears when :

"....... when an external thermostat is in use.

Setbacks can be programmed using the settings in the external thermostat."

My conclusion:

Therefore, for me, I will have to use a Physical Thermostat AND set Field bit 2091 to options 3 or 4.

As a matter of interest , mike , do you have any data on the reasons for the 2091 Motor options ?

I have talked to several Samsung engineers who do not understand these settings!

superb mike !

@iantelescope  

Thanks for the manuals and details of your current settings.  I have read through the latter and there are a couple of comments I would make.  The manuals you have posted are Joule ones, I dont particularly like third party manuals so I have downloaded the latest Samsung manual.

I think you need to forget most of what you have discovered over past years and regard this as a new system.  In many ways, once the replumbing is done, it is and the fog of the past is likely to confuse things rather than clarify them.  Obviously if (when) problems are encountered it may help to refer to the past, but initially I think not.

I would also recommend that you make a note of any parameter you change, both its previous and new value. 

I attach the Samsung manual with comments and my suggested settings on the relevant pages.  Please do check every page up to page 29, I have not made any comments beyond this.  Nor have I 'checked' all the parameters beyond 2xxx, so there may be some you need to tweak when you replumb (I dont think so but cant rule it out).  The comments assume that you do the replumbing , that the system has been tested and works, and that the external thermostat has been disconnected (I think that will happen anyway as a result of the replumbing). 

The aim is to allow you to have working weather compensation with an initial set of parameters, and be able to use the internal temperature sensor instead of your third party thermostat if you wish.  This will, I believe, set the unit so the LWT is controlled by the weather compensation curve, but the room temperature is limited to the value set on the controller (and sensed by the internal temperature sensor).  The effect of this is hopefully that the heat pump operates under room compensation and is active most of the time because the WC parameters are close to optimum, but from time to time (because the weather compensation parameters aren't quite optimum) the room temperature sensor will shut it down for a while.  This will not give quite optimum performance (because optimum performance is when the weather compensation curve is as low as possible consistent with achieving the required room temperature, so the internal thermostat has no effect at all) but should be fairly close and a good starting point from which you can tweak parameters 2021 and 2022, the flow temperatures at your design OAT and 15 respectively.

This should hopefully get your pump working.

Once the heating season starts the aim will be to adjust 2022 and 2021 to be as low as possible.

At the beginning of the season its 2022 that most influences things.  If the house doesn't get to temperature adjust 2022 ghen we have guessed too low, so adjust it up a degree at a time until the house does just get to temperature.  If the house does get to temperature, adjust 2022 down a degree at a time until it doesn't, then adjust it up one degree.  This is, to within a degree, the best (ie lowest) value for 2022.

As the season progresses hopefully there will be a cold spell fairly early on.  At this point you really must ensure that the heating is on 24x7 or very close to that to get lowest cost performance.  When there is a cold spell its 2021 that most influences things.  Follow the procedure as above but substituting 2021 for 2022.  Tweak this again at the height of the heating season (ie when its really cold) for absolute optimum performance.

You may need to go round the loop a couple of times, but don't overdo it, the aim is set and forget!

Once you have established the optimum settings you can experiment if you wish with turning off a few hours at night (eg 10pm-4pm) in the middle-cold season (but not when its at its coldest), and turning off for a longer period (eg from say 10pm-4am and 9am-3pm during the ends of the heating season.  The latter in particular will reduce cycling (which is inevitable at the ends of the season) and shouldn't compromise comfort, in fact it may even improve comfort.  However if you find that this results in you having to turn up the flow temperature, it is almost certainly counterproductive cost wise.

Please note once more that I am not a Samsung engineer, and do not even have a heat pump thanks to my clueless local planning authority.  I am just someone with a degree in physics, a background in engineering, a reasonable capacity to filter the BS from the truth, and who has spent 2.5 years studying heat pumps in the hope that one day he may have his own! 

If you have any questions please do ask (but please try to keep them short).

Feel free to ignore the proposal, but if you do please tell me so that I know not to make further suggestions.

I hope this helps

Posted by: @iantelescope

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Your  pdf on Samsung Screens says that the Water Law screen only only appears when :

"....... when an external thermostat is in use.

Setbacks can be programmed using the settings in the external thermostat."

 

My conclusion:

Therefore, for me, I will have to use a Physical Thermostat AND set Field bit 2091 to options 3 or 4.

Your conclusion is not correct.

Setbacks amount to switch offs in practice and these can be programmed vis the Samsung timer.  They should anyway be used sparingly for minimum cost (please see my post above)

You don't need the water law screen, you can directly adjust 2021 and 2022.  Please see my post above. 

However if you are determined to ignore the internal temperature sensor and use an external thermostat (which Mike-h's information now confirms is unnecessary) then you ned one with a reasonable hysteresis (eg 1C) not a tiny hysteresis and it must be pure on/off not 'smart'.

@jamespa 

"This only works when an external thermostat is in use."

Reference to the Water Law ,aka Weather compensation Screen.

Physical Thermostat or Internal Thermistor ?

Given that  :

1) My Samsung controller sits by my draughty rear kitchen door the internal Thermistor would not  measure my room, or house,  Temperatures accurately.

2) My internal Thermistor being without  :

            a) Hysteresis

            b) Offset controls

            c) Zero controls

            d) Compensation

            e) Timer

the internal Thermistor  would constitute a poor choice of sensor. 

My current Thermostat has all of these controls , but , and it is a big but , comes with a Cycling timer control. 

3) My  Weather compensation Screen is only available when the external Thermostat is in use .,

Consequently , I will have to find a external Physical Thermostat without cycling.

As you say "homely" would fit the bill !

A costly solution ?

Apart from the location which is a poor one (could it be changed?) then, so far as I can see, the manual does not imply or state  the material conclusions you reach about the internal sensor, which has the distinct advantage that it is designed for the purpose. In fact the manual clearly says the opposite and both @mike-h and a Samsung engineer contacted by @editor have confirmed the interpretation.

Hysterisis will be built into the firmware of the Samsung controller itself with an appropriate value for the application.  All the controls you need and access to the WC parameters are still available according to the manual, maybe slightly differently, but they are available.  The easy access 'WC offset' screen is not available, but you shouldn't need constantly to change the WC parameters once they are correctly set up, that is the whole point!  However you can still change them through the fsvs and that is what you will need to do during the setup process I describe.  Some of Samsung's design choices are a bit odd, but overall they make reasonable sense.

I don't know how many wires it needs but it's possible that the connection from the heat pump controller to the heat pump is only 2 wire in which case you could repurpose the wiring to the thermostat.  Worth checking the manual. Alternatively just run a wire to somewhere convenient,  without knowing your house layout I can't advise.  Further alternatively buy the remote sensor add on.

Homely will need a physical connection to the heat pump and will need to be located somewhere representative so presents exactly the same difficulties as moving the heat pump controller.  However, on the positive side it effectively automates optimising the WC curve.

If you wish to use a third party thermostat then you will need to choose it carefully and work out the relevant settings.  You cannot use your current thermostat as a controller because of its characteristics.  You could probably use it as a limiter however you appear to shun this option.

You are, I'm sorry to say, making things unnecessarily complicated and protracted.   

PS to above.  So far as I can see from the installation diagram, the connection between the remote controller and the heat pump is 2 wire.  So you could almost certainly repurpose your thermostat cable and relocate the remote controller where the thermostat is if that makes sense given your house layout.  Im guessing its 12V DC or thereabouts and some well known bus.  You might have a problem with (electrical) noise, but its got to be worth a try. 

So far as I can tell the homely comes in 2 parts, the hub which can be located anywhere within reach of your wifi (and thus likely near your heat pump).  This must be connected to the heat pump and power.  The homely node (temperature sensor) is battery powered and communicates with the hub wirelessly.

@jamespa 

External Thermistor kit Remote-Temperature-Sensor-MRW-TA

During the last two years I have thought about getting the extension Thermistor kit , Remote-Temperature-Sensor-MRW-TA.

https://midsummerwholesale.co.uk/buy/samsung-heat-pumps/Remote-Temperature-Sensor-MRW-TA

I have tested the internal Thermistor at the rear of the LCD panel . However , I abandoned  the idea because

1) With my current set up,  I would still have to use a Thermostat to get any heat . I would need Two thermostats!

  I fully understand that , with the removal of my second Water loop The second water loop would be removed ...................hopefully , now tomorrow!

2) Electrical noise produces E121 errors. The French Samsung Engineer removed the external connection in the hope of stopping the E121 errors.

Unfortunately , removing the external Thermistor cable did not ,entirely,  work, with the E121 errors repeatedly starting .

I get the impression from the very rudimentary , and cheap, External THermistor that Samsung do not consider the Temperatures measured at the Heat Pump itself to be of any significance.

Samsung Homely interface:

I did consider the Samsung Homely interface , MIM-B19N interface.

https://midsummerwholesale.co.uk/buy/samsung-heat-pumps/Samsung-modbus-MIM-B19

Samsung ModBus interface to allow control of Samsung heat pumps by external BMS systems and Homely Thermostats.

Allows for control of a wide range of heat pump operating parameters and remote fault monitoring.

Technical Information

However , I was considering the MiM-B19N for it's Modbus interface solving the de-icing and cloud formation problem of my  Heat Pump, Not "Homely".

Your advice would be appreciated ......... I have tried many approaches in the last two years!.

Posted by: @iantelescope

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2) Electrical noise produces E121 errors. The French Samsung Engineer removed the external connection in the hope of stopping the E121 errors.

Unfortunately , removing the external Thermistor cable did not ,entirely,  work, with the E121 errors repeatedly starting .

Before I comment substantially can you clarify this.  Are you saying you have already the external thermistor.  How do you know the errors were due to electrical noise?

@jamespa 

Electrical noise and the  External Samsung Thermistror.

When asked why the Internal Thermistor , at the rear of the LCD control screen of my Samsung MIM control panel, the French Samsung  Engineer then shorted the  External Connection.

The French Engineer saying that the E!21 errors, I had experienced were a common Fault caused by Electrical noise.

I have experimented with  the internal Thermistor.

The System starts with several E121 errors but then successfully starts.

E121 errors appearing intermittently.

I have NO External Thermostat .

I have, now,  No official means of connecting the External Thermistor.

The External thermistor kit would involve laying yet more cables between the Heat Pump situated at my rear Kitchen door and my Living Room.

I can easily undo the French Engineers short , but, would , when fitting a 12 m long cable probably expose the system to Electrical noise , and , E121 errors.

My Concern would be installing a Cheap and cheerful Thermistor on a noisy 12 M cable replacing a Thermostat with extensive corrections , Hysteresis, offset et al , admittedly with a system producing the apparent effects of "short Cycling".

The other concern is simply laying another cable  replacing a wireless system!

The Samsung Homely interface has only recently been  sold under this designation, being previously described by Samsung as an Modbus analytic tool.!

I originally intended to buy the MIM-B19 N , indeed that was my first question on this, and other , sites, some two years ago!

Posted by: @iantelescope

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My Concern would be installing a Cheap and cheerful Thermistor on a noisy 12 M cable replacing a Thermostat with extensive corrections , Hysteresis, offset et al , admittedly with a system producing the apparent effects of "short Cycling".

The other concern is simply laying another cable  replacing a wireless system!

You simply can't use your existing thermostat other than if you set it well above the desired temperature to act solely as a limiter.  It's clever modulation function, which cannot be disabled, means that it is wholly unsuitable for heat pumps.

Your options are as follows:

a. Use the internal temperature sensor in the Samsung wired remote controller (I'm presuming it's the wired one, but they do also a wireless one please advise if you have this).  If you need to relocate it then so be it, only you can decide where the best place is but the obvious option is to repurpose the thermostat cable and put it where the thermostat is 

b. Use the external temperature sensor extension kit for the remote controller, locate it somewhere sensible.

c. Operate open loop (as regards internal temperature) on water law only, using your existing thermostat as a limiter

d.  Replace your existing thermostat with a suitable alternative that has a hysterisis of around 1C ( which is the hysterisis built into the Samsung controller apparently).  Any less will cause cycling unless the thermostat is used only as a limiter set well above the target temp, in which case you may as well stick to option c .  The thermostat you want may well turn out to be a cheapie model.

e. replace the thermostat with homely.

Any of the above are capable, so far as I can see, of giving a satisfactory result.  The controls will be different between the options. 

Option e is the most difficult and most expensive at the start, but thereafter is likely to prove easiest to manage (basically do nothing, let it sort itself out).

Options a, b, d will give you an easier setup initially than option c, because you can start off with the weather compensation curve a bit high and progressively turn it down until it's at its optimal value, at which point the thermostat/temperature sensor wont actually be doing much.

Option c is the most difficult to set up because you have to get the WC curve 'right' to get the right room temperature.

Once  adjusted correctly options a, b, c, d should all give you nearly intervention free heating, IE your house should get to the desired temperature more or less whatever the weather without having to change settings.

Option e will also do this but will likely cope with a wider range of conditions (eg solar gain, extreme cooking), that might cause a bit of overheating with the other options

Only you can decide!  Personally I would either spend as little money as possible (thus keeping all options open for future upgrade only if necessary) or go full homely.