Octopus are listening.
Then they’re ignoring you and answering different questions purposefully.
Their lawyers aren’t as stupid as their heat pump delivery team.
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@marko
By 'eck, I thought I was a card-carrying cynic with the T-shirt and baseball cap to match, but I see I’ve got serious competition.
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I wouldn’t colour me a cynic. I can fully believe some outfits mean well but fail to deliver without planning to.
But I cant read moral or ethical intentions into contracts where there are opposing clauses signalling intent not to deliver already present. 
I’m going to suggest on LinkedIn that people refusing to release the BUS to octopus until such a time as the installation is confirmed functional using something such as open energy monitor would be wise.
Spend £750 to ensure that your final £7500 payment to octopus is only raised when the job is verifiably complete.
It’s in the BUS scheme for this reason. They couldn’t reasonably refuse. And the good installers will say hell yeah I’ll show you in with it with just as they do now.
Nobody says you can’t play chess with five Queens, right?
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Looking back at this plot with what we now know about the BUH, we can understand better what’s happening. Between 14:20 and 15:00 there’s an extra 500W of electrical input that produces an additional 500W of heat. COP is a measly 3.1. After 15:00, when that boost heat turns off, we see the real coefficient of the heat pump, COPing in at 3.9.
This is just one instance though, and doesn’t fit all the anomalies we’ve seen on this system.
The BUH is now off, permanently I would imagine, I can’t see any circumstances where I will require it.
It is currently 22.6c inside and 4.0c outside according to my Daikin app.
We are producing about 3,500w to maintain this temperature.
I have reduced the flow to 34c and the modulation is 2c. It should run continuously like this apart from defrosts.
COP is about 3.8 which is OK with me.
I will replace more radiators on Tuesday which should improve the situation, but destroy more of my warranty!
It will be interesting to see how it responds.
I am going to heat my outside insulated timber office in the next couple of weeks.
I have a radiator coming that can put out 1,500w at a delta t of 20c and 1,100w at a delta t of 15c.
It should be able to heat the office to 15c to 20c and absorb a good chunk of the heat pump output when required.
It is better than holding the heat pump back like I am now.
My heat loss is about 3.5kw on a day like today so the extra 1kW of heat loss should be perfect, it should mean I get close to a COP of 5 at 35c flow.
I am not sure when my heat loss will approach the 7.4kW as surveyed, it certainly won’t be when it is -2.3c, I think it will need to be quite a lot colder than that!
Turning it down today is working quite well, the house feels better as the temperature is under control and the heat input is steady, just what I wanted.
Hopefully the disabling of the BUH will stop large amounts of unwanted electricity consumption, it was a bit of a shock this morning!
Imagine if you had no monitoring and you knew nothing about the BUH or thought it only came on in extremes cases, you would never know what was going on and you would be horrified at the electricity consumption.
The you would be turning the heat pump off and complaining about the cost of running a heat pump in the comments of every website you could find!
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This is why I like the EcoForest way of doing things with their models names having a range of outputs rather than just a max value.
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That was a great run earlier! what’s the reason for the drop off in performance in the last run? Did you adjust the flow temp target down and it’s having a wobble?
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Hi Trystan,
The house was getting warmer so I dropped the flow by 1c, it caused a hiccup.
The temperature you see is upstairs, downstairs is actually 23.1c, I had to turn it down.
The heat pump just puts out more heat than we need, I struggle to keep the internal temperature under control. Even 36c through my undersized radiators is too much.
This is the last hour, my internal temperature is steady and my heat loss is therefore 2.8kW with 21.7c indoors and 4.2c outside.
You are a smart person, can you see how my heat loss could ever be 7.4kW? at 21c indoors and -2.3c outside?
And because I have this heat pump I am running at the lowest possible electrical input and can only achieve a COP of 2.71
Can anybody honestly say I have the correct heat pump? And yes, I am sitting in my conservatory typing this in a t-shirt!
Can you turn the heat pump off manually and put it back on when the room temp drops below 20-21?
Or is the daikin so poor at restarting a new cycle that the performance is worse!? Cant be worse than 2.7 though right?
I can probably do better than that, I can turn the Madoka down to 20 or 21 and probably reduce how much it goes over the set temperature.
But I hate to admit it, if I do that, the conservatory probably does get a little colder than I would like.
I really need the full 2.8lkW of heat output!
I’m experimenting, the conservatory will be better when I change the radiator.
It’s actually nicer like this, the COP is poor but the temperature is steady, I’m sure the heat will go up and down a bit.
I just thought it was interesting how little heat we actually need to maintain the temperature, or in other words how low the heat loss really is.
I agree that the data is pointing towards a ~4kW heat loss.
What are you doing in the conservatory at 7pm in the winter or are you expanding your living area now to increase your heat loss?
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I don’t bet but if I did I really wouldn’t take that bet on.
I am sure it will be worse, it always takes a lot to get going even after a short pause.
But I will be experimenting more.
It has been fixed on 40c for the last week or so but I thought I would try turning it down a lot today.
I am getting a lot of experience and knowledge about how this heat pump behaves, well certainly in my house anyway.
It may be better running a higher flow in shorter bursts, I would need to do some calculations, perhaps a good idea when I have a stable platform in terms of radiator upgrades.
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That’s the thing, the conservatory is awesome, it is 21c in here even though it shouldn’t be according to the heat loss survey. I don’t know why, maybe it has really special glass, when I look down on it you cannot see through the glass, it is blue, but you can see out from inside. It just doesn’t get cold like you would expect.
And therein lies the problem, theory is great if it matches reality, but our conservatory is not behaving as the heat loss says it should.
It should have been excluded and it would have been but for the initial surveyors error.
Sadly, his error probably wasn’t far off the mark, the heat loss of our conservatory probably is something like 800w
They are not interested in facts and evidence, all that matters is filling in the forms according to the formulas they are either given or derived themselves. No amount of discussion or evidence will persuade them otherwise.
But I am sitting here, living proof, in my house, in my conservatory, consuming less than 3kW of heat to keep the house at 22c when it is 3c outside even though Octopus say it is not possible.
You can all see the data, it is what is happening.
I wasn’t lying, guessing or just making it up when I said my heat loss was about 4kW at 21c/-2c, I know it is because I have heated the house through two winters and I can do basic maths.
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I wonder if anybody could say that it was reasonable for a heat pump to be running at a flow temperature of 32.5c and only return a COP of 2.31.
Does any other heat pump do that?
I am producing exactly the amount of heat the house needs, the radiators are not holding it back, it is the Madoka room temperature setting, it is close to the requested value and so I think it is holding back the heat output.
However, it continues to consume just as much electricity.
It is not bothering me, it just seems like an odd design and is just further evidence that the heat pump is too big for the house.
Yes it’s strange. I have noticed sometimes that if I drop the flow temp on my system that you get a period of low performance while the system volume cools down to the lower flow temperatures, the cop will then start to edge back up again. Not much evidence of it recovering on your run 17:10 to 19:10 so will have to put that down to a daikin ebla range peculiarity …
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I think it is just that it is not designed to heat a house this small, simple as that.
Yes if it wasnt for the strange low performance at startup you could get around the oversized heat pump issue by having some nice long cycles, off 30-60mins, on 30-60mins, but the impression that Im getting is that the Daikin really doesnt like that, or at least the COP’s that result are not nearly as good as other heat pumps manage, especially when running at low flow temps?
Am I right in understanding that if you turn the heat pump completely off now for 40mins, when it comes back on and you target say 36C the performance wont be that great?
I could give it a try.
I predict it won’t be too bad, or not as bad as when it is warmer.
Now it is colder and my heat loss is quite high , it might do better.
I will give it a go
It is off, I will turn it back on in 40 minutes
It hasn’t been this cold recently so now is a good time to try.
My past experience has always been that the first 90 minutes is poor.
If I felt I could run in shorter bursts with any decent efficiency then I would have done it but I always feel like I am going to miss out on the 3 hours of decent performance after waiting 90 minutes for it to get going.
This was the suggestion from Octopus, just run it in short bursts and hard limit the room temperature.
It’s good advice but ignores the evidence of how poor this heat pump is for the first 30 to 60 minutes of a heating run and what you lose by stopping it before it gets to the good bit.
I also find it an unpleasant way of running heating and it was a big reason for moving away from a gas boiler, I never liked the big dollops of heat for 10 minutes in every 30 or 40 minutes, you’re hot, then cool down, then hot again etc etc.
It’s not that nice and I was looking forward to a nice steady room temperature rather than the deviation required with a room thermostat.
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