Posted by: @hjd

Morning all

New member here. I have a 14KW Ecodan system installed in a 370sqm new build (2017). It was pretty poor in terms of efficiency but I have been following all your great suggestions on the forum and I am slowly getting it working much better.

Thanks for all the advice about sticking to weather compensation and also opening up all the actuators and zoned circuits and letting the FTC work it all out for itself.

I now have a couple of questions for your collective wisdom:

- Is the room temperature control (auto adaptation) superior to the weather compensation control option, or do they work in parallel?

- If so, I don't have the wireless thermostat / controller - the FTC5 is in with the cylinder, which is obviously unrepresentative of the house. Should I buy one and would it be relatively easy to self install?

- Is there value in having the wifi adaptor too and then being able to monitor usage via the MELCloud, or is that just a gimmick?

Many thanks

Howard

@hjd, the simple answer about auto adaptation is that we (people on the forum) don't know. I assume auto adaptation works in parallel, that is the FTC5/6 changes the flow temp to achieve the room temp set.  In a way, that's what I'm doing manually.  I have a weather compensation curve that works quite well.  I also have thermometers in the house.  If I want it hotter/colder, I move the weather compensation curve up/down on the FTC6 screen, check the thermometers and repeat until it's right.  E.g if Mrs M goes away for the night I can move the curve down,  if my mother in law comes to stay I might move it up; you get the idea. 

Mitsubishi claims auto adaptation has some sort of prediction/learning, which might help too.  

The easiest way to try might be to move the FTC controller outside the airing cupboard.  For me, that would be easy and I'll probably try it.  The next cheapest way would be to buy/install a thermistor to detect room temp; they seem to be from £20 or so.  The most elegant but expensive solution is the Mitsubushi wireless thermostat.  Looking at the manuals, all of these might need some hardware changes (dipswitches and/or wiring to the FTC/5) but nothing too hard.

I'd definitely recommend the wireless transmitter/Melcloud.

Posted by: @hjd

Morning all

New member here. I have a 14KW Ecodan system installed in a 370sqm new build (2017). It was pretty poor in terms of efficiency but I have been following all your great suggestions on the forum and I am slowly getting it working much better.

Thanks for all the advice about sticking to weather compensation and also opening up all the actuators and zoned circuits and letting the FTC work it all out for itself.

I now have a couple of questions for your collective wisdom:

- Is the room temperature control (auto adaptation) superior to the weather compensation control option, or do they work in parallel?

- If so, I don't have the wireless thermostat / controller - the FTC5 is in with the cylinder, which is obviously unrepresentative of the house. Should I buy one and would it be relatively easy to self install?

- Is there value in having the wifi adaptor too and then being able to monitor usage via the MELCloud, or is that just a gimmick?

Many thanks

Howard

Hi HJD,

Welcome to the forum,

Weather compensation monitors the ambient air temperature, and varies the water flow temperature, dependent upon the parameters set within the FTC controller. Keeping a home at a reasonably constant internal temperature is a balancing act, as the ambient air temperature falls, the heat loss increases, so to maintain the indoor temperature more heat energy must be put in by increasing the water flow temperature. The reports back from members would indicate that weather compensation works quite well.

The heat demand and internal temperature can be affected by other factors, such as solar gain, wind chill, rain effect and human activity, all of which can increase or reduce the heat demand. So, even if the slope of the weather compensation curve has been fully optimised, there will still be variations in the indoor temperature away from the desired level.

Auto adaptation measures not only the outdoor air temperature, but also the indoor air temperature, and acts to fine tune the temperature control to maintain the indoor temperature closer to the setpoint. So if the indoor air temperature were to start to increase due to solar gain or human activity, then auto adaptation would slightly reduce the water flow temperature, to try to counteract the temperature rise. Conversely, a falling indoor air temperature due to wind chill and/or rain effect, would slightly increase the water flow temperature.

Weather compensation with auto adaptation, will therefore maintain the indoor air temperature closer to the desired setpoint, and I do believe it will allow the indoor temperature setpoint to be adjusted, as with a standard thermostat.

Posted by: @hjd

Morning all

New member here. I have a 14KW Ecodan system installed in a 370sqm new build (2017). It was pretty poor in terms of efficiency but I have been following all your great suggestions on the forum and I am slowly getting it working much better.

Thanks for all the advice about sticking to weather compensation and also opening up all the actuators and zoned circuits and letting the FTC work it all out for itself.

I now have a couple of questions for your collective wisdom:

- Is the room temperature control (auto adaptation) superior to the weather compensation control option, or do they work in parallel?

- If so, I don't have the wireless thermostat / controller - the FTC5 is in with the cylinder, which is obviously unrepresentative of the house. Should I buy one and would it be relatively easy to self install?

- Is there value in having the wifi adaptor too and then being able to monitor usage via the MELCloud, or is that just a gimmick?

Many thanks

Howard

If you're happy to keep the indoor temp set at a constant value throughout the day/night, weather compensation alone seems to be more than up to the job.

It's also the easiest solution as you don't have to add anything to the system. 

Try it for a month and see how you get on with it.

@markc Thank you. That is my plan A but good to have it validated. If I need more, it doesn't seem like the additional components are too expensive to source.

@derek-m Thank you Derek. I appreciate your insights. It is remarkably difficult to really interpret what a lot of the 'manuals' are saying!

@kev-m Thank you for sharing your experience and recommendations. I may have to get acquainted with the dip switches!

Just curious but you have a 14kw ASHP in 370m2? It must be a very highly insulated property indeed...that does seem to my amateur eye a possibly undersized pump for what is a very large house. We have a 16kw in a 210m2 house and it copes well but I have no doubt it would be on pretty much permanently if fitted to a significantly larger property. You must have some fairly large electric bills I assume...

Posted by: @hjd

@kev-m Thank you for sharing your experience and recommendations. I may have to get acquainted with the dip switches!

Recent video of someone installing the wireless device in case it is useful in any way.

@siko Good question. We didn't specify it so not entirely sure who did the calcs. That said, for 7-8 months a year it only has to deal with hot water. For the remaining 4/5 it is dealing with heating as well. In recent weeks - and it has been fairly mild - we have been running at about 10-12KWh per day on heating. Not sure if that is good or bad really!

That seems really good, I must admit I don't know what the separate usage is for ours but we are very heavy users of electric and our total usage (water, heat, light, power etc etc) was 843kwh in Oct, probably on track for 1000+ in Nov. So we average prob 30 kwh a day for everything...again I don't know if that is good or not, but compared to before the ASHP came our bills are only marginally higher.....so far!

Posted by: @hjd

@siko Good question. We didn't specify it so not entirely sure who did the calcs. That said, for 7-8 months a year it only has to deal with hot water. For the remaining 4/5 it is dealing with heating as well. In recent weeks - and it has been fairly mild - we have been running at about 10-12KWh per day on heating. Not sure if that is good or bad really!

Hi Howard,

12kWh for a large property is very good. Do you have any heat loss calculations for your property? Where is your location?

Have you considered a solar PV system to both help power your ASHP or help provide hot water from Spring through to Autumn?