OK, I've turned the heating off and put Frost Protection on with min 14 and max 16. I'll post the results of the experiment in the evening!

Posted by: @ecodan-efficiency

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Hi Gary, have you actually used Frost Protection and verified that behaviour? I was told by the official Ecodan support that Frost Protection will not do anything if the heating is "Off".

I haven't used it so it will be interesting to see the results of your experiment.  Tech supports response isn't very clear, what do they mean by if the heating is off.  I would understand if you turned off the controller that frost protection may not be active, but if you just put the heating into prohibit mode (the square symbol) then I would expect frost protection to still work as that is the whole point of it.

Posted by: @ecodan-efficiency

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My current option would be to use a schedule and once a day warm to 10 degrees say, however I can't then get out of that mode while not in the house and it means wiping the schedule I would normally use while in the house.

If you put the heating into prohibit mode before you leave, it will ignore all the schedules in the controller.

Then when you know you are returning you can use the app to set a specific date schedule the day before to turn the heating on, once its back on it will follow the schedule in the controller. You will have to remember to delete the schedule in the app otherwise it will turn back on, on the same day next year.

You will also need to leave the tado set to the required room temperature.

@ecodan-prisoner What's the tado set to, presumably lower than the 14C, I will be interested to see if the heat pump fires up based on the temperature  sensor in the controller.  Where is the controller if its still attached to the main control unit on the cylinder will it may not get cold enough to turn on

Posted by: @ecodan-efficiency

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@davidalgarve Hi, the noise I'm referring to is the noise coming from water pumps that are located near the cylinder.

"Pumps" - plural. Could you give an idea of which Mitsu unit you have, because I have only one built in pump in the Ecodan unit and a second one in the buffer tank/ central heating unit and this latter will be coming out as soon as I can persuade the contractor to do the necessary conversion to volumizer! However, both of them are near silent and could not be heard at 0.5m

@gary I don't use Tado and the Mitsubishi room stat is in the hall and will reach 14 soon enough.

Posted by: @ecodan-efficiency

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@majordennisbloodnok Hi, I have a genuine use case that is causing me frustration where the property will only be periodically occupied in winter. Saying that I should set it and forget about it is not helpful in my case. As described above, I use the system more like a traditional boiler, which means Tado would in theory be adequate. I am aware of "Holiday Mode" - however it is opaque, I don't trust its operation, and is too awkward to use - especially for a 3rd party.

I agree if one were running the unit in the much lauded, although too complicated for mass adoption, flow temp/compensation mode then Tado as it currently stands is not an option (I've not spent time investigating where Tado are at with more sophisticated ASHP specific controls since having the unit permanently on is a complete non-starter for me personally). The idea that I would waste money and countless hours researching modbus/home assistant just to be able to remotely toggle the heating mode and have more than one preset schedule is, I'm sorry, questionable at best.

@ecodan-prisoner, thanks for the extra information; that helps.

However, I think you misunderstand slightly my point. Whilst I wasn’t aware of (or simply missed) the fact the place will only be periodically occupied during the winter, it doesn’t change the fact that whilst it is occupied running the heat pump in its weather compensation fit and forget settings will likely be the most economical option. Holiday mode simply allows the heat pump to take a break from those settings and only fire up to avoid frost damage and so forth. Telling the heat pump to come out of holiday mode a day before the house is occupied again will mean it’s warm enough when people arrive. None of that requires running the heat pump like a gas boiler.

I obviously get your point about wanting to get a break from the noise of the pumps and your plan to get a plumber to investigate the pumps is an entirely sensible course. It does still acknowledge that the problem is not the heat source and so unrelated to either the brand of heat pump or the app used to control it.

As for my comment about hooking something up to the heat pump via modbus, that wasn’t a recommendation. Nor do I think Home Assistant should be a first port of call for fixing a system fault. Home automation systems are for extending functionality, not for fixing fundamentals. Nonetheless, I also mentioned Homely since forum members who have it seem happy with it, and it could represent an alternative way of controlling the Ecodan without having to use Melcloud. Overall, however, the only point I was making there is that Melcloud is just an app and modbus allows alternative ways of accessing ALL the functionality the heat pump offers, meaning there are multiple ways round most problems.

Overall, though, it does feel as if, as long as the pump noise can be resolved, all your issues will be covered by running the heat pump low, slow and constant in weather compensation mode and only using Melcloud to periodically switch holiday mode on or off.

Hi @majordennisbloodnok . It's probably best to leave how I'm operating the ASHP to one side as it's orthogonal to the topic, which is the  limited melcloud functionality primarily. It's a straw man argument.

Regarding Homely (which I hadn't heard of), I don't see any mention of integration with Misutbish on their website: https://www.homelyenergy.com/compatibility/

Fair enough, @ecodan-prisoner. Whilst I suspect the way you choose to operate the heating would affect how much functionality you’d need from Melcloud, you won’t find any disagreement from me about the need for that software to get some improvements.

As for Homely, it looks like you’re right. I can’t see Mitsi mentioned as compatible either. 

@davidalgarve Hi, it's a PUZ-WM85VAA with a pre-plumbed cylinder type thing. They are fairly common.

Posted by: @gary

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but if you just put the heating into prohibit mode (the square symbol) then I would expect frost protection to still work as that is the whole point of it.

You would be wrong! In prohibit mode the Frost Protection mode does not activate - so at least Ecodan support were correct. As it stands this function appears useless.

I'm sitting looking at the app with heating set to prohibit, and of course now I wast to activate it again - why can I just click the little house symbol to toggle the modes! Infuriating.

@ecodan-prisoner You are correct. I have previously investigated the Homely option. It is not compatible with Ecodan and Homely state that they have no current plans to change that.