I have a Mitsubishi Ecodan ASHP with the Mel Cloud app. The system was newly installed to a new build one year ago with UFH but have a number of ongoing issues, the main one being that once the outside temp gets to 7deg or lower it doesn't achieve the required flow temperatures. I have notice that on the Mel cloud app the set temperature slider automatically goes to 14deg and cant be changed. But once the outside temperature gets back to 8deg or above it can be adjusted. Any help would be much appreciated as i am really struggling to get any solutions fro
I have a Mitsubishi Ecodan ASHP with the Mel Cloud app. The system was newly installed to a new build one year ago with UFH but have a number of ongoing issues, the main one being that once the outside temp gets to 7deg or lower it doesn't achieve the required flow temperatures. I have notice that on the Mel cloud app the set temperature slider automatically goes to 14deg and cant be changed. But once the outside temperature gets back to 8deg or above it can be adjusted. Any help would be much appreciated as i am really struggling to get any solutions fro
m the installer.
Welcome to the forum.
The App appears to be showing a room temperature of 8C, where is your controller located? Is your system operating in fixed Leaving Water Temperature (LWT) mode, Weather Compensation (WC) mode, or Auto Adaptation (AA) mode?
@derek-m Hi Derek, by controller you mean the one in the photo below? If so its located in a plant room and set to WC mode I believe. Is there a reason for the set temperature altering itself. Thanks in advance
@derek-m Hi Derek, by controller you mean the one in the photo below? If so its located in a plant room and set to WC mode I believe. Is there a reason for the set temperature altering itself. Thanks in advance
Is the actual temperature 8C in your plant room? If your system is operating in WC mode, then the normal display should show a large '0' zero, or if an offset has been applied some value between +5 and -5. If that is the case then I suspect that changing the value via the App will have no effect.
I don't have a Mitsubishi, so I cannot advise about the delights of MelCloud. There are others of the forum that are much more experienced.
Do you have any other temperature displays within your home?
@derek-m Thanks Derek. I would say its around that temperature in the plant room. The setting is +2 in WC mode. I have the concealed thermostats in the plaster which are connected back to a heatmiser stat in the plant room/landing cupboard.
I was wondering if the setting changing was the reason that the system stops working once it gets to an outside temperature of 7deg or lower. I have had no joy with different engineers and my current monthly electric bill £2400, with this spike due to the ASHP constantly running to get the required heat but failing.
@derek-m Thanks Derek. I would say its around that temperature in the plant room. The setting is +2 in WC mode. I have the concealed thermostats in the plaster which are connected back to a heatmiser stat in the plant room/landing cupboard.
I was wondering if the setting changing was the reason that the system stops working once it gets to an outside temperature of 7deg or lower. I have had no joy with different engineers and my current monthly electric bill £2400, with this spike due to the ASHP constantly running to get the required heat but failing.
I'm afraid that heat pumps and heatmiser's, and the like, don't play together nicely and are often fighting to prove who is in charge.
If you would like to provide details of your system with photo's, it may be possible to get it operating more efficiently.
What is the type and size of your home and do you have any heat loss calculations?
@leftbacks If your room stat is behind plaster is it even able to communicate with the heatmiser in the plant room?
My initial install was commissioned with Heat Miser controls. They and Ecodan/Melcloud don't play at all well. Can be made to work but not efficiently or effectively. I had my installer back to change to all Mitsubishi controls and the system is way better.
Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.
@derek-m The system is a ASHP for heating UFH Ground floor and First floor also hot water with a 300l tank. The home is new build in traditional block and insulated cavity of around 215sq/m (not sure if you double it to include the 2 floors, if so 430sq/m).
I have a Mitsubishi Ecodan ASHP with the Mel Cloud app. The system was newly installed to a new build one year ago with UFH but have a number of ongoing issues, the main one being that once the outside temp gets to 7deg or lower it doesn't achieve the required flow temperatures. I have notice that on the Mel cloud app the set temperature slider automatically goes to 14deg and cant be changed. But once the outside temperature gets back to 8deg or above it can be adjusted. Any help would be much appreciated as i am really struggling to get any solutions fro
m the installer.
Actually I have just been looking at a different problem for a different forum member, and I would suggest that you check the freeze stat function, as described on page B-72 of the attached manual. It would appear that this function fixes the LWT and runs the main water pump to protect the heat pump from freezing water.
Why the adjustment controls on the MelCloud app change or freeze/unfreeze is an issue that I suspect only a call to the MelCloud related support line will be able to answer – it is likely to be quite uncommon. The displayed room temperature is being given by the thermistor within the controller, and is only used when running Room Temp/AA mode. As is the target temperature value you are trying to change. So they should be irrelevant if you are in WC mode – it would be useful to post an image of the main info screen on the controller to check. (If you are in AA mode then this low room temp value may be one factor causing issues.)
One other thing it might be worth trying to check is whether you have up-to-date software on the FTC. My system was installed early last year but I suspect the tank unit had been sitting around in a warehouse somewhere for a bit. On the controller the room temp displayed was -39C, the installers said it was a known problem and so fitted a third party thermostat for controlling WC mode. It was only when a Mitsubishi engineer came in December to replace the outside unit's PCB, and he checked the software running on the controller and said it was out of date, that the updated software resolved that particular issue.
Not sure how you find out though, I'm sure it came up onscreen via pressing buttons on the controller but I can't as yet work out where that info is hiding. The up-to-dateness might be something Mitsubishi support can tell you through what they know via MelCloud.
Mitsubishi EcoDan 8.5 kW ASHP - radiators on a single loop 210l Mitsubishi solar tank Solar thermal 3.94kW of PV
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