What is Energy Integral

[JohnMo]

7 minutes ago, Dreadnaught said:

could easily be set at 15º.

Not really that practical, basics are

 

House at 20,  floor has to be at or above 20. Your return temp will be at or close to the average floor temp before a compressor cycle starts. So then you would need a minimum of 35 flow temp. Not practical, too hot, poor CoP.

9 minutes ago, Dreadnaught said:

run for longer – a good thing for CoP

Not really the longer you run generally the hotter you run, the worse the CoP.

 

Great CoP isn't the only parameter it's also cost to run and comfort. Big screed and overshooting target temperature isn't comfortable, you can take 12 hrs to cool down, then you undershoot target temp. Bigger/thicker the screed floor the more gentle or very well controlled you need to be, to eliminate yo-yo temperatures.

[Dreadnaught]

15 minutes ago, Dan F said:

buggy firmware

 

Good question. Short answer "not any more, I think".

 

Long answer: when I bought the UniTower it had the bug in the controller yes. Then my installer got in to a bit of a pickle and called in the Vaillant flying squad to help (the problem turned out to be installer-error 😄 but that's another story). In problem solving, the Vaillant engineer (with a little bit of encouragement from me) swapped out the controller board inside the controller, which, as you would imagine, I was very pleased to see him do!

 

I now have "351.09.01" on the controller in my UniTower but the version in the heat pump itself is still with the bugged "351.06.07", hence "I think" above.

Edited September 16 by Dreadnaught

[Dreadnaught]

@Dan F, turning to these settings …

• "Room temp. mod."
• "Set-back mode"
• "Set-back temperature"

I am in two minds about these.  The best way to run a heat pump is "low and slow", which would suggest running it 24/7 at the lowest temperature commensurate with a comfortable internal temperature. 

 

But the CoP at night will be worse. So turning the compressor off at night could lead to better CoP overall.

 

These settings above could allow a half-way house. Leave the heating on at night but lower the "target flow temperature" overnight to minimise the impact of the lower temperatures during that period.

 

Any thoughts, @Dan F?

 

 

[Dan F]

12 minutes ago, Dreadnaught said:

but the version in the heat pump itself is still with the bugged "351.06.07", hence "I think" above.

It's the heat pump board that matters, so your unit has the bug and:

i) The default -60º min behaves like -30º min

ii) It ignores any attempt to change the value, eg. to -100º min,

 

This is bad news for over-sized systems and for systems like ours where adjusting this makes sense.

 

See https://energy-stats.uk/vaillant-arotherm-firmware-351-06-07-problems-energy-integral/\

 

I had Vaillant switch mine out FoC, but I don't think anyone else has had any sucess.

Edited September 16 by Dan F

[Dreadnaught]

8 minutes ago, Dan F said:

It's the heat pump board that matters

Ah I see, that's unfortunate news. I will have to see how much Vaillant will charge to swap mine out in the heat pump itself.

 

Did you ask Vaillant to change yours?

 

Edited September 16 by Dreadnaught

[Dreadnaught]

14 minutes ago, Dan F said:

I had Vaillant switch mine out FoC, but I don't think anyone else has had any sucess.

 

Ah, I see. Well done. I have emailed them. Let's see how they reply. 

[Dan F]

22 hours ago, Dreadnaught said:

 

Ah, I see. Well done. I have emailed them. Let's see how they reply. 

Don't ask them for a price. Tell them it doesn't work as designed and you want it fixed under warranty.

[Dreadnaught]

25 minutes ago, Dan F said:

Don't ask them for a price.

 

Good advice.