Posted by: @vlp2024

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(don't tell me this is not possible, mitsubishi, daikin and samsung do it).

How they achieve that? technically.. any pdf?

Posted by: @fazel

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Posted by: @vlp2024

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(don't tell me this is not possible, mitsubishi, daikin and samsung do it).

How they achieve that? technically.. any pdf?

 

I suspect that they just remove the 3-way diverter valve, so that the heat pump supplies both central heating and DHW heating at the same time, though I'm not certain how successful that may be. 🙄 

Posted by: @fazel

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Posted by: @vlp2024

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(don't tell me this is not possible, mitsubishi, daikin and samsung do it).

How they achieve that? technically.. any pdf?

 

Mitsubishi does it by using the immersion for DHW.  It doesn't run ASHP heating and DHW at the same time. 

Posted by: @vlp2024

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@derek-m you just made entire arotherm plus technology useless, by notion it should heat both DHW and UFH in parallel. what i have so far achieved is having hydraulic stations to  up cylinder and then auto  switch to heating and so on, unfortunately no parallel operation. i am going to phone vaillant to clarify if this thing will ever work in parallel. (don't tell me this is not possible, mitsubishi, daikin and samsung do it). my cop so far is above 4.32, electrical heating? i got PV for electricity and solar to water to cylinder

And gas boiler that operates weather compensation does exactly the same, for the simple reason that you need a higher flow temp for dhw than for space heating.

We haven't typically done weather compensation in the UK with fossil fuel burners, but other European countries have.  Thus it's perfectly normal for space and water heating not to happen since simultaneously and nothing special to ashps.  

@kev-m agree

I guess that in principle, with the right plumbing, you could run both together at the ft of the dhw.  Lousy efficiency and the output is divided between the two so possibly lousy performance, but a dhw tank is just another heat sink.

Why you would choose to do this escapes me however.

@jamespa just wanted to understand why would Vaillant not officially admit it: simply cannot run in parallel unless some work arounds like you said implemented, in the end, pipe can feed both ends. maybe modern competition became unpleasant game of plays or smtg else. my mistake was i opted for german made hoping i am getting quality, thats all. i run air to air in two other rooms also, electricity comes from pv plus main electricity. same here, but in that case for top performance one could have get 97/6 only for UFH and end one like 4-5kw for cylinder, seating on top of each other. just ideas.

Posted by: @vlp2024

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just wanted to understand why would Vaillant not officially admit it: simply cannot run in parallel unless some work arounds like you said implemented, in the end, pipe can feed both ends. maybe modern competition became unpleasant game of plays or smtg else. my mistake was i opted for german made hoping i am getting quality, thats all.

All a2w heat pumps work this way so far as I know, because it makes sense, Vaillant is no different.  Ditto gas boilers with weather compensation.

Of course with any device you can do all sorts of things other than the standard ones, but few want to so why are manufacturers going either to confuse their documentation by documenting it, or support it, especially when all domestic a2w heat pumps are the same in this respect.  It's nothing conspiratorial and Vaillant competitors do the same.

The subtle difference is that Vaillant (probably not uniquely) don't interfere with the immersion at all so you are free to use it as you wish.  Some other manufacturers commandeer the immersion for the disinfection cycle, vaillant r290 pumps do the disinfection natively.

Posted by: @vlp2024

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@jamespa just wanted to understand why would Vaillant not officially admit it: simply cannot run in parallel unless some work arounds like you said implemented, in the end, pipe can feed both ends. maybe modern competition became unpleasant game of plays or smtg else. my mistake was i opted for german made hoping i am getting quality, thats all. i run air to air in two other rooms also, electricity comes from pv plus main electricity. same here, but in that case for top performance one could have get 97/6 only for UFH and end one like 4-5kw for cylinder, seating on top of each other. just ideas.

I don't know of any heat pump that can provide both central heating and DHW heating at the same time, which could drastically reduce its efficiency.

It is possible to obtain a DHW cylinder which has a small inbuilt heat pump that solely does DHW heating. I know of one of the forum members that has had one installed.

Since you have a solar PV system, are you not heating the DHW via a power diverter?

@derek-m agree, with solar i get up to 45-55C max , during  sunny days i get temperatures on panels around 110-120 and DHW around 55-58, but those are during hot days( we got plenty of sun anyway). i only raised this point because of expectations, you know when you expect ( falsely assumed). you right and solar panels cover 260-280 days min (2 panesl, 2sqm each). i am extremely happy with solar heating. i trust arotherm will do its work too, maybe needed a bit of playing around. house is 170sqm with water UFH 100sqm, rest with electrical UFH. it was extremely difficult to plan arotherm plus, i dont know why we got HEX< maybe to save money on glycol, but then why we need glycol if we got 280 sunny days and -5-15 is a rare commodity here. i should have gone with simple install, my mistake. what i am happy about is with UFH thermostats and how easy it was to split into zones ( 6 of them per room) , all RF based, using shk.

Posted by: @vlp2024

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@derek-m agree, with solar i get up to 45-55C max , during  sunny days i get temperatures on panels around 110-120 and DHW around 55-58, but those are during hot days( we got plenty of sun anyway). i only raised this point because of expectations, you know when you expect ( falsely assumed). you right and solar panels cover 260-280 days min (2 panesl, 2sqm each). i am extremely happy with solar heating. i trust arotherm will do its work too, maybe needed a bit of playing around. house is 170sqm with water UFH 100sqm, rest with electrical UFH. it was extremely difficult to plan arotherm plus, i dont know why we got HEX< maybe to save money on glycol, but then why we need glycol if we got 280 sunny days and -5-15 is a rare commodity here. i should have gone with simple install, my mistake. what i am happy about is with UFH thermostats and how easy it was to split into zones ( 6 of them per room) , all RF based, using shk.

Where are you located?

I don't wish to appear too negative, but the consensus of opinion is that having lots of zones with a heat pump is not the most ideal way to operate. For best overall efficiency, it is thought that keeping the maximum amount of heat emitter capacity active, means that the heat pump can operate at the lowest required Leaving Water Temperature (LWT), which increases the efficiency of the heat pump. Having zones switching on and off reduces the overall heating capacity, requiring a higher LWT and possibly causing premature cycling to occur, which again can reduce efficiency.

@derek-m exactly, from arotherm plus perspective there is one zone, then it gets into zones by selector