Thank you for your patience and explaining my questions. There is -so much I understand , but may be over thinking , it’s just that my first month with Octopus on Cosy seems to be high(yes it’s cosy, make no mistake ) ! It has revealed a cost from 1st Jan to 27th is £509 , which If devide  cost by KWh comes to .24pence so moving on I hope I can improve this . Onwards and downwards, cost wise!

Total kWh 2210 all on Cosy bar 1 day. 

Posted by: @alfapat

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It has revealed a cost from 1st Jan to 27th is £509. Total kWh 2210 all on Cosy bar 1 day. 

That sounds quite high, but of course I dont know much about your house or how much DHW you use.

My total January electricity consumption (minus 1 day) is 1076kWh and that includes charging my car (albeit not a lot for this).  I have a 200sq m 1930s house solid wall (no cavity!) house with a couple of modest modern extensions, 300mm loft insulation, partial internal wall insulation (so some walls are still solid brick).  The measured heat loss @-2 is about 7kW.  By no means a passivhaus!  Mind you we don't use much hot water.  I keep more or less the whole house at 20C 24*7.

@jamespa Yes just a bit !

Only hot DHW of significance is a small bath once a day. There are only two of us . Thanks

currently seeking info on Mod bus compatibility with Gen 5 . 
Fingers crossed!

Posted by: @alfapat

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@jamespa Yes just a bit !

Only hot DHW of significance is a small bath once a day. There are only two of us . Thanks

currently seeking info on Mod bus compatibility with Gen 5 . 
Fingers crossed!

Good luck on the modbus.  I think you are in with a good chance, these units are based on aircon units used in commercial settings where modbus will likely be how the building management communicates.

Do you have the ability to measure the temperatures on the emitter side of the buffer tank, it would be useful to get a handle on these and in particular the difference between flow temp in from the HP and flow temp out to the emitters.

Yes I do, I have another set, I will place them shortly. 

Incedently I notice from the sAMSUNG CONTROLLER that the oat side temp outside is 0.6c and two weather stations are saying -1.2c , so at least its not far out.

Attached earlier photos with HP and rads in circulation

 Black probes being HP

Later without , when I came back to house all systems quiet

OK, the most interesting thing is the temperature drop across the buffer measured between flow from HP and flow to radiators.  I dont think I can see that in the photo.

Posted by: @jamespa

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OK, the most interesting thing is the temperature drop across the buffer measured between flow from HP and flow to radiators.  I dont think I can see that in the photo.

So , on the first two photos the Hp is delivering 43-5c and through to Rads its 37.4

2nd two photos its 36.6c to rads its 32 .8c remembering system is idle , yes it seems to be quite a difference on the first active pics.

I can take more when I see that the circulation is on ?

Posted by: @alfapat

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Posted by: @jamespa

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OK, the most interesting thing is the temperature drop across the buffer measured between flow from HP and flow to radiators.  I dont think I can see that in the photo.

So , on the first two photos the Hp is delivering 43-5c and through to Rads its 37.4

2nd two photos its 36.6c to rads its 32 .8c remembering system is idle , yes it seems to be quite a difference on the first active pics.

I can take more when I see that the circulation is on ?

 

To the final question yes. 

If the HP is delivering 43 and through to rads its 37, then you are losing about 12-20% in efficiency as a result of the buffer tank, which is going straight onto your electricity bill..

Repost when you have more info with the system running.

@alfapat Your aim (when the system is running and has settled down after a few minutes) should be to match the temperature feeding out of the LLH to the emitters with that of the flow temperature into the LLH as closely as you are able, likewise the temperature of the return flow entering the LLH from the emitters should be as close to that of the return flow out of the LLH to the heat pump. 

Too fast a flow from the secondary pump return to the LLH is likely to cause unwanted disturbance to the water in the LLH and cause mixing - this would cause the returned (cooler water from the emitters) to recirculate within the LLH rather than meekly following the direction of flow back to the heat pump. It is a balancing trick with compromises and a need for a little dose of pragmatism - but it will pay dividends! Regards, Toodles.

Posted by: @jamespa

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Posted by: @alfapat

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Posted by: @jamespa

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OK, the most interesting thing is the temperature drop across the buffer measured between flow from HP and flow to radiators.  I dont think I can see that in the photo.

So , on the first two photos the Hp is delivering 43-5c and through to Rads its 37.4

2nd two photos its 36.6c to rads its 32 .8c remembering system is idle , yes it seems to be quite a difference on the first active pics.

I can take more when I see that the circulation is on ?

 

To the final question yes. 

If the HP is delivering 43 and through to rads its 37, then you are losing about 12-20% in efficiency as a result of the buffer tank, which is going straight onto your electricity bill..

Repost when you have more info with the system running.

 

                                               37.1C and 32.7 Emitters

All pumps , two on HP AND ONE CH pump are on setting three.

Attached is flow signal , not sure how you read that whether it’s the rh side of flow indicator or LH 

OK, so 41.9 in from heat pump, 37.1 out to rads, drop of 5C = 10-15% efficiency penalty.  Not sure how the return to the heat pump is higher than the return from the rads though, this can be the case if the flow rate from the heat pump is higher than the flow rate to the emitters but in that case the expectation would be that flow temp to emitters is close to flo from HP.

In summary no idea what is going on (one of the reasons to dislike buffers!).