@tim441  AI?

@morgan i should have made clear ... LG call their version of weather compensation "AI"

Posted by: @tim441

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@morgan i should have made clear ... LG call their version of weather compensation "AI"

I had no idea LG called their weather compensation AI... not confusing at all 🤣 

As good a place as any to drop this video:

Increasing weather curve during winter? 

We are now in the dead of winter, the lake is starting to freeze over, nights have been well sub zero and solar has been very little. I've notice that the internal house temp has been hovering lower and lower the past few days (reducing from set point of 20 to 19C) so I've bumped up the WC from 0.7 to 0.75 and might need to go to 0.8. I do have the aerotherm set to active so would have thought active would be enough to compat the loss alone. 

Perhaps the persistent cold has robbed the walls of final heat and with solar being poor (we are south facing at 1000m in Spain so get very good solar) the increase in the WC is to offset this drop is solar. 

I'm going to assume this is normal? Do others experience this? Our house is 80-100cm stone walls and very little insulation. 

Typing this out makes it clear this is quite logical and reasonable explanation and outcome. 

Posted by: @jamesh

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Increasing weather curve during winter? 

 

We are now in the dead of winter, the lake is starting to freeze over, nights have been well sub zero and solar has been very little. I've notice that the internal house temp has been hovering lower and lower the past few days (reducing from set point of 20 to 19C) so I've bumped up the WC from 0.7 to 0.75 and might need to go to 0.8. I do have the aerotherm set to active so would have thought active would be enough to compat the loss alone. 

Perhaps the persistent cold has robbed the walls of final heat and with solar being poor (we are south facing at 1000m in Spain so get very good solar) the increase in the WC is to offset this drop is solar. 

I'm going to assume this is normal? Do others experience this? Our house is 80-100cm stone walls and very little insulation. 

Typing this out makes it clear this is quite logical and reasonable explanation and outcome. 

This is normal. I’m a fiddler and vary the heat curve slope up and down according to to season. The Vaillant algorithm used on active (and inactive will be worse) does not have enough gain in the control system to set the room temperature constant. Yes you could leave the heat curve to the highest setting and allow it to cycle more in shoulder season but that reduces your COP and increases your bills (at least a bit).

Mick Wall has done a lot of monitoring of his Vaillant and concluded that Havenwise does a better job for house comfort and he explains it more fully than I can. Havenwise isn’t essential if you are willing to to fiddle as the season changes.

https://energy-stats.uk/sensocomfort-room-temp-mod-inactive-active-or-expanded/

Posted by: @jamesh

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I'm going to assume this is normal? Do others experience this? Our house is 80-100cm stone walls and very little insulation. 

Here in the south of the UK I don't find the need to vary the weather curve but I do switch from 'no room influence' to 'expanded' mode (which acts as a limiter) at either extreme of the season, when solar gain can easily dominate house loss during the day. 

For most of the season 'no room influence' keeps the house much more stable than I could ever achieve with a boiler/thermostatic control.

Our house is tolerably insulated with a mixture of 200mm solid brick walls + internal wall insulation, 200mm solid brick walls + no internal insulation and 200mm lightweight block.  7kW @-2 for 200sq m.

Okay thanks both. 

Yes the house is very nice and has sat at the desired temperature untill now, so it works great and I'm very happy. 

I'm not interested in have wise, quite happy to push a few buttons now and again. 

Interestingly we've been well under 0 for a few days now and dipping to -9C overnight. I've actually had to reduce the weather curve (0.8 to 0.7) as it was overheating, even with active enabled (active is not strong enough for it's job imo). It seems when it's really cold my house is fine. The issue is mild temps 2-7C and higher humidity, low solar  where the algorithm falls down for heat required. 

Posted by: @jamesh

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Interestingly we've been well under 0 for a few days now and dipping to -9C overnight. I've actually had to reduce the weather curve (0.8 to 0.7) as it was overheating, even with active enabled (active is not strong enough for it's job imo). It seems when it's really cold my house is fine. The issue is mild temps 2-7C and higher humidity, low solar  where the algorithm falls down for heat required. 

Thats quite plausible particularly with radiators. 

Radiator output is not a linear function of surface temperature unfortunately, its (usually) proportional to temperature^1.3 (there is a range of aluminium radiators claiming a much lower exponent - ie closer to linear).  This means that, if the WC curve is linear, the rads will output more in relation to the loss at lower OATs and less in relation to the loss at higher OATs.  Depending on how exactly the curve is set up the discrepancy, a degree or so, may manifest itself more or less anywhere in the range, but most likely at middle OATs. 

As a further complication, if your heat pump modulates its water pump speed to keep a constant DT (some do) then the discrepancy between a linear FT variation and the ideal for radiators is greater than for heat pumps that keep their water pump speed constant.

@jamespa 

Interesting thanks. I do wish the vaillant app would let me build my own weather curve. There is a lot of scope for improved user functionality - though I respect they don't want plebs messing with stuff.