Posted by: @batpred

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For heating, I believe all we will need is to have it working as a programmable thermostat with different temperatures for different times of day and also vary by weekday (not necessarily for 7 days, but to have some flexibility). 

I am not a Mitsubishi owner so can't speak with authority.  The question you should ask yourself is do you want to vary flow temperature with time of day (and oat of course) or use a thermostat as an on off switch to do setback/set forward, with ft depending on oat only.  Most heat pumps will do the latter, relatively few do the former.  I can't comment on what Mitsubishi r290 pumps do.

Posted by: @jamespa

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I am not a Mitsubishi owner so can't speak with authority.  The question you should ask yourself is do you want to vary flow temperature with time of day (and oat of course) or use a thermostat as an on off switch to do setback/set forward, with ft depending on oat only.  Most heat pumps will do the latter, relatively few do the former.  I can't comment on what Mitsubishi r290 pumps do.

Ah, I should have been clear, I do not mean flow temp but the target room temperature. I only anticipate having a lower target at night as we find it better for sleeping. 

Posted by: @batpred

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Ah, I should have been clear, I do not mean flow temp but the target room temperature. I only anticipate having a lower target at night as we find it better for sleeping. 

 

Yes but there are two ways to do that, the first is to turn the heating pump off altogether using a thermostat (because that is what will happen), then turn it on again when the room has cooled.  This results in room temperature control by thermostat.  The second way is to reduce the flow temperature.  This results in heat pump control by flow temperature.  

They have different characteristics.

Another, arguably better, way to achieve what you want is simply to reduce the room temperature of the room where you sleep permanently, which is how the mcs design rules work.  Obviously this assumes you use predominantly different rooms for sleeping and living.

How quickly does your house cool.  Reducing target temp doesn't reduce house temp.  Loss from the house does that.  This may be too slow to achieve what you want in which case differential room temperatures is the way to go.

Posted by: @jamespa

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Obviously this assumes you use predominantly different rooms for sleeping and living.

Typically yes, if we exclude nodding off watching US "news" 😀 

Posted by: @jamespa

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Another, arguably better, way to achieve what you want is simply to reduce the room temperature of the room where you sleep permanently, which is how the mcs design rules work. 

Yes, the surveyor asked and I mentioned we would want the sleeping area to be 3C or so below the rest. Even if at night it could be more..

Posted by: @batpred

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Posted by: @jamespa

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Obviously this assumes you use predominantly different rooms for sleeping and living.

Typically yes, if we exclude nodding off watching US "news" 😀 

 

I would seriously consider just making the room temps different then.  You can then consider strategies like raising temp at night to take advantage of a tou tarrif.

My house, even though it is 1930s, doesn't cool sufficiently quickly for a nighttime setback to deliver comfort benefits without compromising late evening comfort.  Differential room temps solves this problem.   Yours may be different of course.

Posted by: @batpred

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We are considering an Ecodan ASHP R290, they seem to be solid and well designed.

For heating, I believe all we will need is to have it working as a programmable thermostat with different room temperatures for different times of day and also vary by weekday (not necessarily for 7 days, but to have some flexibility). And to use weather compensation with an external sensor. 

As the owner of a 8kW Ecodan R290 maybe I can help. 

While we don't use it, and just use weather compensation, I believe the Auto Adapt mode can do all of this. 

But as James, in subsequent messages, has suggested, maybe more simply designing the system so that bedrooms are always heated to lower temperatures might be better? 

Posted by: @batpred

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For the hot water, probably just set one target temperature and the times of day we will need it to warm the hot water tank to it. And the legionella cycle of course. And also have a holiday mode button..

The Ecodan controller can do all of these. 

Posted by: @batpred

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Essential is for all to be "wired in" regarding the controls are managing the pump, etc - without dependency on the internet during operation. 

There's no dependency on the Internet, all of the fundamentals can be controlled locally. 

Posted by: @batpred

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A nice to have is if the controls would also provide some information on overall consumption and cost. 

You can view consumption and production values on the controller, the same data is available via their Internet service MELCloud (if you want). The production values are reasonably accurate, the consumption values less so. 

Posted by: @batpred

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Below is an extract of the parts for one of the estimates we received. Just wondering if these controls meet our simple requirements?

• Mitsubishi Ecodan 290 Monobloc 8kW £4,462
• Ecodan FTC Wireless Thermostat PAR-WT60R-E £169
• Mitsubishi Incidentals £503
• Ecodan 8kW pack £1,195

Yes, either the first or last bullet point should include the FTC7 controller, either directly or as part of one of Mitsubishi's hot water cylinders. 

Are you planning on having a Mitsubishi or 3rd party hot water cylinder? I ask as Mitsubishi cylinders have a LLH (low loss header) attached that installers will use but you probably don't want/need. 

@batpred, others have already mentioned the sense behind running the heat pump at a steady weather comp and just having emitters throttled back so that sleeping areas are slightly cooler than living areas.

Personally, I agree and it fits in with the way we run ours, and about 5 years' experience shows it's an effective and efficient strategy. Beyond reiterating that point, I also wanted to make a comment or two on your other points.

Whilst the Mitsi wall boxes for changing settings aren't particularly intuitive, they are workmanlike and most certainly can operate without the Internet. Internet connectivity (via an optional wifi adapter that may or may not be included in your quote) is purely to link in with the Melcloud service and, as a result, allow for the app to work (and, therefore, remote interaction); it's certainly not essential, although being totally reliant on the wall box is not the most user-friendly.

My personal suggestion would be to invest another £35 and get an ethernet dongle that plugs into the FTC's CN105 socket and talks MQTT to a remote MQTT broker. That would allow you get the Mitsi talking directly to your Home Assistant, get all the stats you might want and get full local control. You can get a variant of the dongle that has a second CN105 slot so that you could then daisy-chain the Mitsi wifi adapter onto the end and still have it working with Melcloud in parallel - that's the way I have it running.

The dongle itself is based on a ESP32 board, and the firmware is available on Github (@f1p is the member here who developed it). As a result, you could do all of this for free if you had a spare ESP board kicking around, or at least very cheaply if you had to buy any CN105 sockets to solder on. However, the dongle already preloaded with the firmware is also an option.

The relevant Github repository is here.

The main reason I bring up this third party MQTT approach is your mentioning wanting to run the heat pump in auto adapt mode. Mitsi's approach is perfectly acceptable but the dongle's firmware introduces a greater ability to fine-tune room influence and offsets which, for a tinkerer like you with Home Assistant, may well be an attractive option.

I hasten to add, though, that in the event of Home Assistant crashing, the dongle would still continue to work as configured and, if you wanted to, it would be only a moment's work to remove the dongle from the equation in total. Moving back to your bullet point list, I'm not familiar with the last two items. I don't suppose you have links available, have you?

Posted by: @robs

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Posted by: @batpred

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Below is an extract of the parts for one of the estimates we received. Just wondering if these controls meet our simple requirements?

• Mitsubishi Ecodan 290 Monobloc 8kW £4,462
• Ecodan FTC Wireless Thermostat PAR-WT60R-E £169
• Mitsubishi Incidentals £503
• Ecodan 8kW pack £1,195

Yes, either the first or last bullet point should include the FTC7 controller, either directly or as part of one of Mitsubishi's hot water cylinders. 

Are you planning on having a Mitsubishi or 3rd party hot water cylinder? I ask as Mitsubishi cylinders have a LLH (low loss header) attached that installers will use but you probably don't want/need. 

Thank you, very useful, it seems it would fit the bill. In our case the reserved zone being 1m may make the difference, but I would be confident, it is a a very solid offering. 

We are very unlikely to use a manufacturer's cylinder as we need  large capacity but have a tight space to fit it in. So far, Joules and Tempest seem to be the best options.   

Posted by: @majordennisbloodnok

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The dongle itself is based on a ESP32 board, and the firmware is available on Github (@f1p is the member here who developed it). As a result, you could do all of this for free if you had a spare ESP board kicking around, or at least very cheaply if you had to buy any CN105 sockets to solder on. However, the dongle already preloaded with the firmware is also an option.

The relevant Github repository is here.

The main reason I bring up this third party MQTT approach is your mentioning wanting to run the heat pump in auto adapt mode. Mitsi's approach is perfectly acceptable but the dongle's firmware introduces a greater ability to fine-tune room influence and offsets which, for a tinkerer like you with Home Assistant, may well be an attractive option.

Thanks, I did have a go at programming an ESP board but something did not work the first or the nth time and eventually moved on. 😉 So I never got the dev environment fully working. 😏 

Posted by: @majordennisbloodnok

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I hasten to add, though, that in the event of Home Assistant crashing, the dongle would still continue to work as configured and, if you wanted to, it would be only a moment's work to remove the dongle from the equation in total. Moving back to your bullet point list, I'm not familiar with the last two items. I don't suppose you have links available, have you?

I am afraid no link, it seems that those last two are unique options to package for parts (and perhaps labour..).  I will use a feature checklist should I progress the estimate further.. 

Posted by: @batpred

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Thanks, I did have a go at programming an ESP board but something did not work the first or the nth time and eventually moved on. So I never got the dev environment fully working.  

Drop me a PM with any questions, can assist as much as possible if you wish to visit it again