If there is a setting i must have it set! My Ecodans have been off since 20th may - only doing hot water and legionella

I am not aware of a setting of this type but would be pleased to learn.

Perhaps not as sophisticated as you might want, but I use the "Schedule Timer" to limit heating to the months October to March which broadly suits Algarve weather conditions. It doesn't affect DHW.

Better still use Melpump which shuts it down completely (no standby), except for the times that DHW heat input is called for.

Posted by: @clockworks

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Is there a setting on the FTC6 that tells it to keep the heating off if the outdoor temperature is above a certain level?

I'm running in weather compensation mode, with the wireless remote set 1 degree above where the curve keeps the rooms in the colder months. As the weather warms up, and heating isn't really needed to be comfortable, the heating keeps running at the minimum curve flow temp.

I currently just turn the wireless thermostat down 2 degrees, but a couple of people reckon that there's a setting in the FTC6 that just turns it completely off when it's warm outside. I've looked through the installation manual, and I can't find it.

In effect, that's precisely what weather compensation is supposed to do, so if yours isn't doing that then the curve could probably do with a bit of a tweak. What is your curve's upper OAT and flow temperature? Over the years, I've just let the heat pump stay on all the time and let the compensation curve deal with whether or not the heat pump should run. I have found several times where it has chosen to activate the water pump to circulate water without doing any actual water heating, hence using almost no energy.

I certainly haven't found any setting to tell the heat pump to prohibit heating above a certain OAT, but there is an alternative and that is to look at schedules. Your in house display wallbox thingy allows you to specify separate heating and DHW schedules (page 35 of the FTC6 manual). Under the Schedule menu item, there are two schedules and schedule 1 is normally set to "Jan to Dec", leaving schedule 2 redundant. Once you go into schedule 1, you can set the times of day for doing heating or DHW, as you'd expect. If, when you're about to select either schedule 1 or schedule 2, you also have an "edit" option so you can change schedule 1 to be (for instance) June to September and schedule 2 to be Jan to May and Oct to Dec. That way, you can then tell the system to keep heating off during schedule 1 and turn heating back on for schedule 2, whilst leaving DHW enabled under both schedules.

For my taste, that's far too clunky since we might have an unusually hot May or a more rapid Autumn onset than normal, so I don't look at schedules at all. @davidalgarve mentioned Melpump which, if you have already decided to take out a subscription for, might well be an answer, especially if you use the little CN105 dongle installed locally to give greater control. Whilst I don't use Melpump (because I'm allergic to paying for subscriptions) I happen to use that same CN105 dongle but linked to Home Assistant so I can automate the heat pump being put into "prohibit heating" mode if the OAT is at or higher than the set internal room temperature. That then stops me wasting that small amount of energy for running the water pump unnecessarily.

This is one of many examples of how I can benefit from greater local control and automation through Home Assistant. It's not for everyone, however, since there is certainly a learning curve. If you fancy tinkering, it's a route I'd suggest you look into. If not, though, I'd say your best bet is to tweak the upper end of the compensation curve so the heat pump doesn't want to do any heating when it's warm outside and then let the heat pump stay on all year.

...or just set your schedules and room temp in MelCloud if you are using the Mitsubishi remote thermostat. I set the room temp to 12C in the summer season schedule so no heating.

Posted by: @abernyte

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...or just set your schedules and room temp in MelCloud if you are using the Mitsubishi remote thermostat. I set the room temp to 12C in the summer season schedule so no heating.

I wouldn't personally set schedules in Melcloud since it requires the heat pump to be permanently connected to t'Interweb and any temporary glitch in connection means Melcloud schedules aren't honoured during the outage. Not a big deal but a layer of complexity one could do without.

As for lowering the room temp, though, that's a good shout. A simple solution (assuming as mentioned before that the compensation curve's upper end goes down to a low enough flow temperature as to actually stop heating happening) and very visible.

My WC curve is set at 32 degrees at OAT 15 degrees. 48degrees at minus 2. Settled on these numbers after a lot of tweaking. I haven't touched if for a year, and it gives me a very consistent 21.5 to 22 degrees in the hallway, and comfortable temps in all the rooms, mostly 21 to 22 degrees (unless it's sunny). Main bedroom is held a little lower with a TRV.

When the heating is required, I'm very happy with the comfort levels - as long as there's not a lot of sunshine.

Season scheduling won't work, as the dates can vary massively from year to year. We can have a mild April and May, then a few cold weeks in June.

Being a 1960's bungalow, the windows are very large, and a lot of solar gain in different rooms at different times of the day.

I tried Auto Adapt mode, but it really couldn't cope when it was relatively cold outside, but sunny. We had a lot of over/undershoot and cycling. Ended up less comfortable and costing more.

I'm using Home Assistant, but all I can do is adjust the wireless thermostat from my dashboard, and see the flow temps.

I've got smart temperature and humidity sensors in every room already, but just for dashboard display.

I keep thinking it would be great if I could use these temperature sensors to either automate the thermostat setting, or better still, add an offset to the WC curve to get proper whole house auto adapt. Basically automate the "plus/minus" offset on the FTC control panel.

Will this CN105 dongle give me the control needed for proper automation in HA?

Edit:

I just googled "cn105 dongle", and it looks like you can make one with an ESP32. I've got a bunch of these, as I've been playing with ESP Home in HA to make some custom sensors.

Posted by: @clockworks

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My WC curve is set at 32 degrees at OAT 15 degrees. 48degrees at minus 2. Settled on these numbers after a lot of tweaking. I haven't touched if for a year, and it gives me a very consistent 21.5 to 22 degrees in the hallway, and comfortable temps in all the rooms, mostly 21 to 22 degrees (unless it's sunny).

...

If you are going to stick with the native Mitsi controls, I'd just change the top end to 23.5 degrees at OAT 24 (which is a literal extrapolation of your current curve and so won't change anything from OAT 15 degrees downwards). I think that'll solve your immediate problem unless others more learned see any flaw in my thinking.

Posted by: @clockworks

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...

When the heating is required, I'm very happy with the comfort levels - as long as there's not a lot of sunshine.

Season scheduling won't work, as the dates can vary massively from year to year. We can have a mild April and May, then a few cold weeks in June.

...

Totally agree.

Posted by: @clockworks

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...

Being a 1960's bungalow, the windows are very large, and a lot of solar gain in different rooms at different times of the day.

I tried Auto Adapt mode, but it really couldn't cope when it was relatively cold outside, but sunny. We had a lot of over/undershoot and cycling. Ended up less comfortable and costing more.

...

We have a very similar problem; an 8 metre East facing wall that is pretty much all glass. Solar gain is significant. A lot of what we're doing will be very relevant to you.

Posted by: @clockworks

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...

I'm using Home Assistant, but all I can do is adjust the wireless thermostat from my dashboard, and see the flow temps.

I've got smart temperature and humidity sensors in every room already, but just for dashboard display.

I keep thinking it would be great if I could use these temperature sensors to either automate the thermostat setting, or better still, add an offset to the WC curve to get proper whole house auto adapt. Basically automate the "plus/minus" offset on the FTC control panel.

Will this CN105 dongle give me the control needed for proper automation in HA?

Edit:

I just googled "cn105 dongle", and it looks like you can make one with an ESP32. I've got a bunch of these, as I've been playing with ESP Home in HA to make some custom sensors.

You've no idea what a rabbit hole you've just looked down - in a good way.

Last things first, will the dongle give you the control you need - yes. It exposes everything you can see in Melcloud, it allows you to control everything you can control on the in house display and it adds some extra features of its own. Oh, and it's all done locally so if you lose your Internet connection you can still continue regardless and additionally it refreshes every few seconds rather than the slower updates of Melcloud. Finally, depending on the connections you choose for your hardware, you can insert the dongle between the FTC and the Mitsi wifi adapter so you don't even need to choose between the dongle and Melcloud; you can have both at the same time.

Now for a bit more of an explanation.

The code for getting an ESP32 board to do the necessary was created by a Github user called f1p, and he happens to also be a member here (@f1p). The code is provided open source, and it so happens he also sells prepackaged ESP32 modules on Ebay. If you fancy messing about with the ESP32 board and connectors yourself, feel free and you can just flash his code onto it, but I happened to choose the lazy route and get an already configured one with the extra port for daisy-chaining the Mitsi wifi module to. In fact, since I had the odd wifi dropout in the loft where the FTC happens to be, I ended up getting a second module that's ethernet rather than wifi, but once again with that extra daisy-chaining slot.

The extras are where I find significant benefit.

Firstly, @f1p has provided his own alternative weather compensation curve. The Mitsi curve is more a straight line and so is relatively inflexible, but the dongle's curve can be an infinite number of separate point, so describing an S curve, for instance, is a doddle. If your requirements need it to tail off gently or suddenly drop off a cliff, this is the way to achieve it.

Secondly, the FTC already has a manual offset capability; the option to tell it to increase or decrease the flow temperature from the compensation curve by a set number of degrees. The dongle also provides for this, but there are now two extra offsets; one for solar gain and one for wind chill (in fact, they're just three offsets so they could be called anything you like, but solar gain and windchill are the scenarios @f1p was designing for). That means that, in Home Assistant, I use a combination of the sun's elevation and position (from the Sunlight Intensity integration) and the cloud coverage (from the Metar Weather for the nearest airport) to decide how much to reduce the heat pump's flow temperature to compensate for solar gain and the difference between the forecast temperature and the forecast "feels like" temperature (from the Met Office integration) as a starting point to decide how much to increase the heat pump's flow temperature for compensating for wind chill. The dongle nets these off and applies the result.

Thirdly, the dongle can accept from Home Assistant regular updates on OAT and IAT from third party sensors if you have them - as you say you have. This may or may not be what you want, but the flexibility is there.

Fourthly, the dongle has its own version of auto adapt so that its compensation curve can also take into account the actual room temperature - whether that temperature comes from the Mitsi IHD or a third party sensor. You don't have to use this feature but it's there nonetheless.

In short, the little dongle - home made or prepackaged - linked into Home Assistant gives you all the control I think you'd want. As an aside, I've even added some automations to spot when there's an Octopus saving session being advertised, opt into the new session, turn the heat pump off 15 minutes before the session starts and then turn it back on again 15 minutes after the session has ended. If you can think it up, you can probably do it.

I think @majordennisbloodnok has put together an excellent summary of my adapters.

I would just note while there are ESPHome projects available I would be a little bit cautious. I chose to use MQTT for flexibility and broad compatibly 

1. ESPHome broke all Serial communication for 3months last year following a bad update, then again for a few weeks at the start of this year. Not ideal for a device which requires stability and makes me think ESPHome is a bit more suited to simpler projects.
2. MQTT in home assistant in particular allows dynamic discovery - which is an amazing feature for heat pumps and the different configurations people have, e.g. if you have a FTC7+R290 then I can make your hot water maximum adjust to 70C to match the real unit or even interchangable between air to air & air to water units. With ESPHome you would have to recompile yourself with new setpoints.
3. With MQTT you can also send over the internet (or across network segments) too, helpful if you want to pair with services like MELPump. ESPHome is limited to only local connections with HA

Major and f1p - thanks for the very detailed replies.

I've had a read through of the dongle documentation, and it looks ideal for what I want to do - plus a lot more that I never thought of!

I've already got MQTT set up, used in conjunction with my Sofabaton X2 remote to trigger HA automations, so I basically understand the concept.

At the price the dongles are selling for, seems pointless trying to make my own, plus it's a good way to support the project.

Can you confirm that it comes pre-flashed and ready to plug in, or do I have to install my own firmware via ESP Home?

Yup, ready to plug in. The most awkward part I found was finding the socket on the FTC6 board to plug the dongle into. Other than that, @f1p's instructions were fine.

Posted by: @clockworks

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Can you confirm that it comes pre-flashed and ready to plug in,

Yes, Pre-flashed plug & play