@smit360 ok so you can use the +- 5C adjustment on there to move the water outlet temp up and down quickly, once ithe system is stablised at the new run temp , allow 60 mins at least for run temp to stabilise, more than that for the effect on the house, you start to get a feel for whether that's keeping the house warm or not you can go into the settings and change the weather comp values. this is a long iterative process, it will take you days. Plus you need a number of days at the difference ends of the temp scale of course.

buffer - integrated, nice. cleaner install than separate. buffers are always going to decrease efficiency somewhat (lots of discussion in other threads), but you've got one so we can try to optimise it. Please invest in a set of these amazon cheapo thermometers.  Tape them tightly to the buffer tank  pipes, there will likely be 4 . insulate over the top with 28mm pipe insulation so we get pipe temp not air temp.  work out which is which - 2 will be to the heat pump  (flow and return) 2 will be to the heating system (flow and return). We are going to need to know these temps later.

thermostats - just thinking, you are going to need something to tell your system to switch off when too warm, unless you achieve weather comp perfection, which very few do, you won't literally run it 24/7. I presume that your 3 zone stats been setup to call for heat from the heat pump? Are they going though some additional logic ? or are they just all wired individually to the B21 terminal (logical OR) i.e. if  any zone calls, the heat pump runs?

Either you are going to need to make one of the zone stats the sole master to determine whether the heat pump runs or not. This is not desirable if it has a "boiler attitude" to cycling and run times (small hysteresis, lots of on/off switches per hour). OR , you will need to make the samsung controller itself be responsible for that. In which case it needs to be in a  place where it can see a reasonable view of your desired temperature, it needs to be in the lounge or hall. not airing cupboard. Its easy to move, its got a 2 wire low voltage cable in the back that is trivial to extend.

@iancalderbank thanks for the detailed reply. Last few weeks we've been moving back in and making the house as liveable as possible. It's like Beirut at the front and all new at the back. 

I've attached my initial 201,202 figures. I've since changed these to the standard ones found online 201: 15, -2 and 202: 32, 47. I have 203 set to 35 and 50 and 2041 is using those values? 

Regarding temps, I've attached the linked thermometers to relevant pipework at the tank with readings as followed. ASHP Flow - 38.8, ASHP Return - 34.8, Heating Flow - 35.2, Heating Return - 30.9. Outdoor temp on the display was 5.8. 

The ASHP pump is set at 55w/1.4m3/h. The heating circulation pump is set on constant speed mode at 3 bars. (No visual with that one.) 

I've checked that stats, they go into a junction box before the Samsung board. They are all linked together in there and then one wire sent to B21. The heating circulation pump is also in B21. Do you think the best method would be to extend the cable for the Samsung controller and mount that on the hallway?

Also, another question relating to the external run of pipework. The current setup is approximately 6metres, lagged and clipped to an outside wall in trunking. Due to the size of the heat pump, there was nowhere for it to be sited on what will eventually be a patio on the back of the house (currently a 4ft drop from the rear doors.) 

My two options are:

- Build a steel-framed/block and beam suspended patio with access underneath to get to the heat pump and allow air flow.

- Move the heat pump to after the patio area which would extend the pipework by approximately 4metres, possibly running the underground and connecting to the wall mounted pipework. (I did see mibec DHP pipe online for this.)

I feel the latter will probably be a better solution for access with regards to servicing/maintenance, I'm just unsure of the impact if any the extra run of pipework will cause.

@smit360 @healcol and @ken any practical suggestion/recommendations here with the final installation spot for this heat pump?