Posted by: @alfapat

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Is that not the flow rate shown on that page I posted, 16L/pm or is that a completely different thing you’re talking about, and what is the WC please. Weather compensation?

Its the actual flow rate, after you have bypassed the buffer/pump, that you are interested in.  Your controller should have a read out and I would make a note of the current value.

WC = Weather compensation, what Samsung call water law.

@jamespa Hi James , I thought I would draw out what is the best I can do , my system arrangement to help understand what I have in place , if you want any thing that’s missing ,I can add , but it’s fairly basic. 
I hope it clears any doubts you may have in my set up.

Nice drawing, Im glad you did it.

have you really got two pumps in the primary, one on the feed one on the return.  If so are they (and the pump on the secondary) all the same model?

I guess its silly of me to ask why because you have no way of knowing.  Are either of them controlled by the heat pump and if not do you know if anything controls them or do they run continuously?

Posted by: @jamespa

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Nice drawing, Im glad you did it.

have you really got two pumps in the primary, one on the feed one on the return.  If so are they (and the pump on the secondary) all the same model?

I guess its silly of me to ask why because you have no way of knowing.  Are either of them controlled by the heat pump and if not do you know if anything controls them or do they run continuously?

Yes , I have three circulating pumps , one from HP and one circulating and one return, They do go on and off but I cant tell in what sequence , At the moment it must be the oat or something as the TRv ;s are open fully and the Thermostat is above room require ments by 0ne degfree and never get there as advised.

So costs are high as I see it but comfortable heat in house .

@alfapat are they all the same model?

Is there any way you can tell what they are wired to?  

The answers might affect the strategy for buffer removal.

Yes all the same model , with a selectable speed as mentioned before , selectable manually by a button , but not sure if controlled otherwise. I will follow if I can the wiring . As far as I can see , they all go to the Samsung box nearby.

The picture shown is the Ch pump , I will check as the picture shows all three lights on the pump speed , usually it shows only the speed selected. 

Ok. I'm going to seek some advice on operating two pumps in series, which effectively you already have but when the buffer is removed becomes more directly connected.  I suspect it's best to bypass 2 pumps, on in the secondary and one in the primary, but let me first ask someone who may have experience of this.

Please try to trace what they are wired to.

@jamespa Pumps in series are not a problem, the flow rate on the pump is approximately the same and the head is about 70% more (not double).

@alfapat, your problem is flow and distortion caused by incorrectly scized pumps, lack of knowlage and poor design. If your house is warm, but your bills are high, simply removing the buffer tank and secondry pump (with some re-programming) you will have significant savings, possibly as much as 40%.

@heacol Thanks for the info on pumps and head (Im presuming when you say pumps in parallel you also include in series - as here); with that and the measurements @alfapat has already done I think we can be pretty confident he has enough pump head to push through his heating system at sufficient rate.  I have seen it said that pumps in series are a problem but never understood how that could be the case (unless grossly mismatched so one is sucking at the other).

I believe @alfapat is already convinced to remove/bypass the buffer tank and secondary pump and thanks for confirming my suspicions here.  I'm hoping he is going to trace the wiring to the pumps to find out what is controlling them, so we can work out what reprogramming might be necessary (other than the obvious of adjusting the WC curve down and pocketing the money saved!).

@jamespa (Im presumeing when you say pumps in parallel you also include in series - as here); you are correct and I have corrected my post. Mismatched pumps in series, are not a problem as long as there is flow at the duty point. Grossly mismatched would be a problem, but anyone who knows anything about pumping, would not do that (however it is common in this country).

I would suspect the secondary pump (after the buffer) is controlled by a third-party thermostat which also controls the heat pump through an input. The primary pumps will most likely be controlled by the heat pump. To get this to work, significant programming alterations need to be made. It is not just as simple as removing the buffer, second pump and thermostat.

Posted by: @heacol

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I would suspect the secondary pump (after the buffer) is controlled by a third-party thermostat which also controls the heat pump through an input. The primary pumps will most likely be controlled by the heat pump. To get this to work, significant programming alterations need to be made. It is not just as simple as removing the buffer, second pump and thermostat.

Thanks.  Im guessing the same.  I am not a Samusng expert (or indeed a heat pump expert) but Im hoping the changes needed, to get it running open loop on pure WC as a starting point (which it is more or less currently, albeit with a buffer) are in FSV20xx only plus whacking the third party thermostat up to max.  The plan is to make the plumbing switchable so it can be restored to current config.  Its a very old installation so warranty isn't an issue, just function.

Incidentally its clear (at least to me) from this forum that there is a need for trusted, intelligent, knowledgeable people to provide a 'diagnose and fix' service for heat pump installations.  Whether anyone would be prepared to pay the rates that they would demand is of course another matter!

@heacol and thanks James, I will look at all the labelling to see if any of the pumps differ in Spec. I already have two spare ones chucked aside in the loft , discarded when th 9 kw unit was remeoved ! I will trace the wiring  as well

Yes, the house is a lot warmer and consistant ,with changing to balancing with lockshields,  but using up a lot mor kw I fear . Over the last 7 days with oat ranging between -1c to 5c roughly its averaged at 77.7kw/h.