@judith thanks…. Every day a school day.

tomorrows lesson - filters and strainers- how many microns? 😂😂😂

@editor This is my current WD Curve. Daikin 9kw installed by Octopus last September. Still working on the fine tuning and looking to learn as much as I can about how our system works.  Had the system fail 3 times with a blocked HP strainer, so its not been a great experience so far. Really appreciate all the contributions from the forums to gain more info and tips. Especially the information regarding the minimum LWT of 30C.  This has really helped with the operation of the system and it looks a lot more stable.  Unfortunately I only found this information after the cold snap at the beginning of the month, when the system gave up for the third time with a blocked strainer, having used over 64kw for the day.  Octopus have been and reset the system to "Their" settings. 50C @-8C and 25C@20C OAT.  I let it run for a few days but the consumption had increased dramatically.  Changed back to what I think is more in line with my expectations and comfort.

Can anyone confirm my understanding of the WD curve. At the Higher OAT I have set 10C and the minimum LWT is set to 30C .The line of the curve is then straight across all temperatures above 10C.  Does this mean the heat pump will maintain 30C LWT across all the higher temperatures?

Yes mine does, my warm end of the curve is set to 33@7⁰ on my ecodan I can bring the whole curve down by off setting -4, when I do this my system runs at 29⁰ @7⁰ it will then stay at 29⁰ at 8⁰ 9⁰ 10⁰ 11⁰ but at 12⁰ it starts to cycle when it does that I turn it off for some reason it won't go below 29⁰ LWT, flow temperature.

Ecodan Weather Compensation Curve. I've been running my Ecodan in Auto Adapt at 20C 24/7 without any real problems except that, when it reached the set room temperature of 20C it tended to go into stand/by mode. It wasn't switching on/off frequently (cycling) my understanding was/is that is should modulate down and continue to produce a lower flow temperature to maintain my room temperature. I asked my installer if the minimum flow temperature was too high stopping it from modulating down sufficiently, cause it to simply stop. He advised that auto Adapt could not modulate down very far, so better to put it in weather Compensation Mode. Attached photos of how he has now set it up. apart from the Curves looking rather odd, it hasn't prevented the HP from going into stand by mode when room temperature is reached. In particular, one Curve suggests 34C at 25C outside, even though top left of the Curve is at 50C? questions are, how should the curves be set when in Weather Compensation, AND, if I return to Auto Adapt, how do I adjust lower flow temperature to avoid it going into stand by mode? Thanks

Posted by: @davidalgarve

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Samsung ASHPs

For reference, Samsung calls it Water Law and simply allows setting the flow temperature at two points creating a weather compensation 'curve' like the chart above. For a constant flow temp, the two points can be set at the same flow temperature giving a flat 'curve'. I initially set mine to be 30C at an ambient temp of 15C, and 40C at -2C outside temp, but it's easy to adjust and tailor to your property as you collect data points over the first winter.

Once the curve is set, the flow temps (LWT) can be easily adjusted on the front screen by toggling up or down +/-5C which is very useful for making small manual adjustments for solar gain or wind chill, or if you just feel a bit colder than usual on any given day.

@plasfron Need a few more details about your heating system to be able to comment fully but here are some questions/comments for starters.

Is it all radiators or UFH or a mix?  If it has UFH are they on separate zones?

Other than the main controller are there any other mitsubishi or 3rd party thermostats controlling the heating either upstairs or downstairs?

The main controller looks to be attached to the white Ecodan box (FTC).  In auto adapt mode the temperature either has to be measured from the main controller or a Mitsubishi wireless thermostat, so if the main controller is in the airing cupboard attached to the water tank and you don't have a separate Mitsubishi wireless thermostat you won't be able to use auto adapt accurately as it will be measuring the temperature of the airing cupboard rather than a more suitable location in the house.

Auto adapt uses the weather compensation curve but is allowed to deviate from it by margins set in the controller where as pure weather compensation just sticks to the curve you have in your images.

Looking at the curve in your images, its set quite high, looks to be 40C at 0C outside and 35C at 10C outside, however, you have then offset this curve by -5C which is what is displayed on the main display so its actually running 5C below those values which is more realistic but depending on your house and the rest of the heating system may be too high.

If the ecodan hits the target temp it will turn off which is what you are seeing, you need to set the thermostat target temp above your comfort level and then work out what weather compensation curve you need to maintain your comfort level but not reach the thermostat target temp.

Then it will keep running unless you get a lot of solar gain and then the house will be above your comfort level and it will shut off till it cools back down.

@gary Thanks, I have a Mitsubishi Remote Controller in the hall which I use when in auto Adapt mode. Just one zone, the whole house, with nine radiators only, with TVRs fully open.

To repeat, I've been running in AA, but, as it was switching off when it reached set temperature of 20C, 24/7, because it couldn't modulate down far enough, installer switched it to Weather Compensation with the settings you see here.

I don't use third party controls such as thermostats.

Aim was to allow it to modulate down to provide a lower flow temperature (ticking over) to maintain set room temperature, rather than switching off/on, which is how an Air Pump should operate.

Unfortunately, switching to WC hasn't cured this, so considering going back to AA which, frankly, is more convenient.

Question then is, how should the Curves be set up, in order to operate in Auto Adapt?

@plasfron I don't believe it matters which mode you are running in, if your thermostat is satisfied it will turn off the heat pump, that's why I said you need to set it above what you desire then reduce the curve so you can get to the comfort temperature you want without getting too high to hit the thermostat limit.

As autoadapt can deviate from the curve I'm not sure what it will do when it approaches the thermostat limit, it may try and reduce the flow temp or just continue till its shuts off the heat pump.

If you want to give autoadapt free reign you will need to adjust the offsets that autoadapt can use they are located in the service menu, operation settings, thermo diff adjust, these are how far you allow it to deviate from the weather comp curve in either direction.

Default is set to +/-5C but you can extend the bottom end to -9C.

LG Therma V weather compensation is called AI and is set in the controller.

Using AI... my curve is miserly - but works for us.

16kw Therma V

Old building with modern extension

Octopus Intelligent Go - with batteries & pv

Controller in warm room so using external thermostat (in heat pump) and "Water Only" for weather compensation

AI settings:

Water heating set temp 29/48

Outdoor temp for auto mode -4/15

LWT for auto mode 30/45

We keep the house around 20 - 21deg

We get some solar gain so manually tweak thermostats as necessary. With LG the curve can be temporarily tweaked as much as + or - 5deg with simple change at controller. Generally not used a lot but sometimes use + if cold day & night at zero or below. - used if solar gain likely

These settings are probably on low side for most people but seem to work for us.

MCS heat loss calcs were 28k kwh pa.

At a guess our true heat loss is around 20-22k kwh/pa (parts of old building heated to lower temps)

ASHP last 2 years has used metered 5800kwh/pa

In 2022 we used over 8000kwh without AI

Perhaps SCOP around 3.5?

With old controller 3.05.5a we don't have great data. Newer controllers have better info

Hot water heated to 47deg overnight at cheap rates. Daytime H/W schedule 40deg to top up.