Posted by: @jamespa

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Indeed; I would recommend you focus on what's wrong/what they actually need to change 

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Absolutely. My mention of the legal side in retrospect implies I was suggesting getting into litigation which is at this point unhelpful. Not how I intended it to come across, though; apologies.

Posted by: @majordennisbloodnok

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Posted by: @jamespa

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Indeed; I would recommend you focus on what's wrong/what they actually need to change 

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Absolutely. My mention of the legal side in retrospect implies I was suggesting getting into litigation which is at this point unhelpful. Not how I intended it to come across, though; apologies.

 

No need for apologies, just cautioning about getting too hung up on all of the mistakes (of which there appear to be plenty enough to make a case) and instead focus on the outcome.

@bami I think if the heat loss documentation matches a 8kW heat pump then you have a very good case as "not fit for purpose"

Alternatively if that is too convoluted, sell the 12kW model and purchase a 8kw or maybe even 5kw depending on what you discover. Its an easy job just to swap it out.

@jamespa 
@bontwoody

Heat loss calculations found and attached.  Although of course the room areas are incorrect

From this do I assume the 8276 equates to a roughly 8kw pump?

Changing the subject, DHW came on today as per new schedule.  I set it for 2 hours at 47C between 2pm-4pm, then had a bath at 5pm & the water was still too hot.  So now turned it down to 45C and will see how that goes.

@bami yes. 8kw = 8000w

I would change the areas in the heat loss calc to the correct ones and recalculate the heat loss. 

It doesn’t mean that it is the correct heat loss but it will determine if they were correct to fit a 12kw  heat pump or not. 

Posted by: @bami

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Heat loss calculations found and attached.  Although of course the room areas are incorrect

Was there any more detail or it that it?  Its over 8kW, and by the time they make an allowance for DHW they would be able to argue for 12kW based on this.  But I would lay money its a typical gross overestimate that much of the industry does.  Your oil consumption and house size/construction is nowhere near consistent with 12kW, more like 6kW.  

As @bontwoody says its worth plugging the correct areas in for a rough check.  You may be able to make a case for them to swap it out which in the long run would be beneficial.

@jamespa 
@bontwoody 

I can't just input the proper floor areas on the installer calc as he missed out 2 windows and patio doors.  So I used this online calculator (don't know if it's the correct one but it asks the right questions re floors, walls and window areas)
https://www.plumbnation.co.uk/heating-calculator

Using this calculator, heat requirements come out at 5460.94 watts, so do I assume from that a 6KW pump would suffice?

I'm going to ask the installers to re-do the heat loss calculation and we'll see what the outcome is.

@bami I think a lot of people use heatpunk as a heat loss calculator. To me 6kW would sound about right but this is an area where installers regularly over size their systems often due to an over estimate of air changes per hour. I would guess that the majority of people get an oversized heat pump to a varying degree and getting any redress is incredibly difficult in the current system.

To Bami and others with Samsung pumps. I notice that the controller is set to "Heat".

Is this correct, or should it be set to"Auto" for Water Law (as is mine)?

@broadsman I run mine on water law but with regards thermostat as a limiter on my warmest room so the controller does display HEAT.

@broadsman Not the faintest clue!  When I read about how to change the water law settings it never mentioned changing the Heat to Auto, so I've just left it on Heat.

But like Bontwoody I also have a house thermostat which tells the pump what time to set back and when to come on if house temp gets too low.

I'll ask the installer tech guy if he ever gets back to me!

Posted by: @bami

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But like Bontwoody I also have a house thermostat which tells the pump what time to set back and when to come on if house temp gets too low

Don't lose sight of the fact that at some point to optimise your settings, I recommend to turn this to max and 24*7 operation then adjust your water law curve down.  I suggested a procedure quite some posts ago.  Your choice of course but lowest possible flow temperature=lowest operating cost and greatest comfort in most cases, and is definitely the place to start.