@jamespa 

MIM-B19M + Homely ?

An excellent summary of my Thermostat options, James.

I will , initially,  wait until I have removed the Heat Exchanger ......................now tomorrow !!

My current inclination, for the Thermostat problem,  is to initially keep the current Physical Thermostat.

I will then experiment with increasing the Thermostat Temperature by +3 C on my current settings.

I will then adjust , by whatever means, (Field bits 201/202/203 or Water law display 2091 options 2,3 or 4)  the Water Law graph hoping to get  a stable house Temperature during the day.

But I will Wait until the outcome Tomorrows upgrade  before deciding!

Mod-bus

If the removal of my Heat Exchanger , now tomorrow , works .....................I will initially, try and  install the MIM-B19N Mod-bus interface as intended some two years ago.

Homely :

I would, if affordable , then install Homely on the MIM-B19N Mod-bus Analyzer .

MIM-B19N fitting ?

My original problem with the MIM-B19N was that it did not physically seem to fit inside my Samsung Heat Pump cabinet in my Garden.

Everything appears to be odd on my  Samsung!

Mod-bus RS485 ?

Once installed the MIM-B19?N would transmit on a RS485 Mod-Bus cable.

I would install a RS485 cable from my garden Samsung cabinet to my house.

Homely attaching  to the  RS485 Mod-bus cable.

Original Mod-Bus Control cables:

The Czech  Electrical engineer, employed by my "installer" fitted standard electrical cables between my Samsung Heat Pump in my Garden and the Control box within my kitchen.

When asked "why he did not install the correct RS485 cabling " he replied that "it would make little difference, standard electrical cables would work   without a protective Earth Sleeve   ".

 Three days later the , Czech Engineer announced that he would be returning to the Czech republic because of the "appalling standard of my "installer".

Do I need to replace the standard electrical cable with earth screened rs485 cable?

Ok.  

Not sure what the point in the modbus interface is unless you definitely intend to get homely. 

You will need to reconnect the thermostat to the demand for heat terminals on the Samsung and check first that it's actually electrically compatible.  Traditional thermostats in the UK are 230V whereas most heat pumps need zero volt contacts.  I have no idea about the Honeywell, you may need a relay.  You could also not bother reconnecting it, all you would lose is the temperature limit function which has relatively little value anyway!

You will need to set 2091,2092.  I would suggest to 4 which allows the heat pump to sniff the lwt form time to time to decide whether to switch on or not according to the WC temp setting ( the manual is a bit obscure on this, but I think that is what option 4 is for). Several other of the parameters in the annotated manual I posted will also need to change.

Posted by: @jamespa

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Not sure what the point in the modbus interface is unless you definitely intend to get homely. 

...

...or another third party monitoring and/or controlling device. Home Assistant or OpenHAB spring to mind, but even home-grown python scripts would be able to make good use of the ability to control locally rather than through a manufacturer's portal.

Posted by: @majordennisbloodnok

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Posted by: @jamespa

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...

Not sure what the point in the modbus interface is unless you definitely intend to get homely. 

...

...or another third party monitoring and/or controlling device. Home Assistant or OpenHAB spring to mind, but even home-grown python scripts would be able to make good use of the ability to control locally rather than through a manufacturer's portal.

 

Fair enough, I have the impression that @iantelescope doesn't have that in mind but as you say it's another option.  First task is to get the heat pump running as it's maker intended!

@jamespa 

MIM-B19N ?

My original reason for using a MIM-B19N was :

1) to run the internal Diagnostics within the Garden cabinet of the Heat Pump.

The large Clouds of water vapour produced by my Heat Pump raised alarm with my neighbours and , with one neighbour in particular , a large Care home.

I ran both Diagnostics within the Heat Pump itself, with the Heat Pump displaying it's results on a HEX format LCD character display. This in the intense cold of a December morning following a large cloud incident!

2) to determine the status of the de-iceing routines after a cloud producing incident within the Heat Pump itself.

How much power was consumed during de-iceing ?

At What Temperature was de-icing triggered.?

Both of these questions could only be answered with the MIM-B19N interface.

Homely  and the MIM-B19N?

Homely is Now advertised as the Solution to Samsung Thermostat problems.

Homely uses the  preferred Samsung MIM-B19N interface.

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

Many thanks for  your Homely  recommendation!

Posted by: @iantelescope

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Homely is Now advertised as the Solution to Samsung Thermostat problems.

I don't see that in the advert and am not sure what 'Samsung Thermostat problems' you refer to.  Homely is really a more sophisticated controller.

@majordennisbloodnok 

Without MIM-B19N How?

Many thanks for your intervention.

How could I interrogate the status of my Samsung and run the Samsung internal diagnostics without a Mod-Bus , RS 485 interface?

The Official interface , the MIM-B19N is £140 ...........

I , usually , have no programming problems.

many thanks

@jamespa 

Sorry, @jamespa , Midsummer are advertising the MIM-B19N as THE interface from SAMSUNG to Homely.

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

As you, yourself , said , @jamespa 

" Homely are reputed to be an excellent Thermostat "

With the addition of a MIM-B19N Mod-bus interface I can examine the performance of both the thermostat and the Heat Pump itself.

as @toodles  said , highly recommended.

I was disputing your characterisation of it as 'the solution to Samsung's thermostat problems.' Sofaik there are no problems with Samsungs temperature sensor/thermostat to 'solve'.

Homely isn't a thermostat, it's a sophisticated flow temperature controller, more sophisticated than the Samsung one.  That doesn't mean that there is anything wrong with the Samsung one, just that if you pay more you can do better. 

Likewise a Rolls Royce is 'better' than a mini (in many circumstances) but that doesn't mean that there is anything wrong with a mini.

Noted that you want to use the modbus interface to interrogate the Samsung, and wasn't aware of that.  Perhaps you could also write your own homely.  The objective is simple, min flow temp (or cost of you have tou tariffs) to achieve desired comfort level.  The challenge is to define 'desired comfort level' and to integrate into the control a forward looking view of the oat (and possibly solar gain).

Posted by: @iantelescope

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@majordennisbloodnok 

Without MIM-B19N How?

Many thanks for your intervention.

How could I interrogate the status of my Samsung and run the Samsung internal diagnostics without a Mod-Bus , RS 485 interface?

The Official interface , the MIM-B19N is £140 ...........

I , usually , have no programming problems.

many thanks

A bit of miscommunication I think, @iantelescope. @jamespa was questioning what use the modbus interface would be if you weren't sure you'd get a Homely box. I was pointing out that the modbus interface's value would not just be limited to Homely, but also to one of several alternative third party controlling/monitoring systems such as Home Assistant.

Nonetheless, whether you choose Homely or a different home automation system, modbus is the ideal and perhaps only way to interrogate and control your heat pump locally.

@jamespa 

Do I REALLY need to remove the HEX ?

 To my consternation I have discovered that the Homely installation instructions contain :

Notice the Heat Exchanger in the installation instructions!

Notice the pair of motors etc etc !

My system would appear to be one of many !!

@jamespa

Hi James, how is your sanity holding up?