@matthannon do bear in mind they’re a bad idea (TRVs in general with the exception of bedrooms) with an Air to Water #A2W based (i.e. radiator/UFH based) #HeatPump so shouldn’t be used, nor pushed.

An open circuit that doesn’t restrict flow is very very important to get the efficiency levels they’re rated & good for.

Take a look at #HeatGeek (Adam Chapman) @petereastern , @kenbone , @stevewebster56 , Nathan Van Gambling for references to this

@EsTresidder
I’d say something like ~50C at DoT (e.g. -3C)..

We run our Daikin fitted by 🐙 in Sep’22 at 40C @ -7C, & 24C @ 15C (weather compensated) in an old 1880s farmhouse with I’d say basic insulation levels & ~21C inside

Although remember: an #A2W #HeatPump should always be weather/temp compensated, so should not run that hot for many hours/year

Another point to note: the the power output of the unit generally drops with a higher flow temperature, hence the low ish figure I stated.

@Fascinatorfun @janrosenow

And also, tell people 2 look around in towns/cities etc. as most businesses are heated (&cooled) by the #AirToAir #A2A air conditioning variety of #HeatPump & these are often in poorly insulated buildings

Business &commercial sector in U.K. seem much further ahead with this transition, as they appreciate the #A2A variety *also* does cooling in the summer which the #AirToWater #A2W variety can’t when paired with radiators

They just work if designed/installed well

@kenbone @jesseb4me @stevewebster56

At ~09:30 today in below screenshot I turned off all but one off the 2.8kW (heating mode) indoor units, set it up a degree C or so higher, and as you can see, it’s humming along at ~450watts for the most part which is very different behaviour (in a good way). It doesn’t like them all on in above ~>5C temperatures it seems.

It’s almost as if #A2A #MultiSplit is the very the *opposite* of #A2W #HeatPumps where more emitters/water volume is ideal.

@jesseb4me @stevewebster56 @kenbone

Thanks for that. Useful info.

It’s interesting to see such a difference between #A2A and #A2W heat pumps of similar output. Optimised differently?

Conversely, on Nov 21st, it got down to 1-2 Celsius overnight, &his #A2A came into its own, & put my #A2W to shame. The Daikin really struggled with that temp &defrosted loads, but the Panasonic only defrosted once that night (half mile away from each other):

Nov 21st got to 1 - 2 Celsius:

@kenbone @stevewebster56

Long runs today, I think I’ve dialled things in fairly good so far. #HeatPump #A2W