I think the installer is out of their depth as reading between the lines they have only done it before where the system is in the house and there was quite a bit of staff turnover during the installation/commissioning.  Also different staff came for different parts of the job (radiators versus ASHP) and I don't think they were talking to each other.  To be fair, I'd assumed that they were project managing things, but in hindsight I should have checked that or got our builder involved.

As far as I can tell the system is not running on weather compensation, so won't be as efficient as it could be.  It's all a learning curve!  I need to figure out whether to go back to the installer, or find someone else to come and review (I'm assuming Mitsubishi won't be much help, but I haven't tried that route).  Thoughts apprecaited!

You have various options.

If it is not too difficult the display part of the Ecodan controller could be moved into your home and located in the main living area, which would allow the auto adaptation function to be utilised should you wish to do so.

Alternatively you could leave your system as is, and use the Weather Compensation mode (WC) in conjunction with the Hive thermostat, provided that the Hive thermostat does not have a cycling function that cannot be disabled.

The objective should be to use any room thermostat (Hive or otherwise) as a high Indoor Air Temperature (IAT) limiter, such that it is normally calling for heating and enables the heat pump to operate. If the IAT should increase above the desired level due to solar gain or human activity, the room thermostat would disable heat pump operation until the room thermostat resets.

Normal IAT control should be achieved by the heat pump controller varying the Leaving Water Temperature (LWT) dependent upon the Outside Air Temperature (OAT), which in turn varies the heat loss from your home.

More information about your system may be helpful so that more detailed advice can be provided. Photo's are also useful.

I've spoken to the installer a couple of times and they are not sure, but would a simple solution to move the ecodan controller to the house (instead of with the integrated boiler unit in the garage)?  We have a cable conduit that we could use, but would appreciate any thoughts/ideas before I go back to the installers

In short, yes.

Then turn the hive (if it is connected which seems to be in doubt for some reason) up to a temperature about 2C above that desired, so the main temperature control is down to the heat pump.  You may need to adjust the WC curve and/or set it to auto adapt if this has not already been done, but it sounds like it probably has.

If you wire the hive in, the behaviour unlikely to change unless the heat pump autodetects the third party on/off signal and uses this to override its own controller, or you also change some other setting on the heat pump to tell it to ignore its own controller and respond only to the hive.

Exactly my point, once wired in to the FTC and appropriate dip switches changed the Ecodan will ignore the main controller and use the Hive to call for heat.

Currently, we have no idea to what if anything the hive is connected to.

Alternatively, as we have both said move the main controller into the house.

Like most things there is more than one way to solve the problem

Understood

If you wire the hive in, the behaviour unlikely to change unless the heat pump autodetects the third party on/off signal and uses this to override its own controller, or you also change some other setting on the heat pump to tell it to ignore its own controller and respond only to the hive.

Exactly my point, once wired in to the FTC and appropriate dip switches changed the Ecodan will ignore the main controller and use the Hive to call for heat.

Currently, we have no idea to what if anything the hive is connected to.

Alternatively, as we have both said move the main controller into the house.

Like most things there is more than one way to solve the problem

I wouldn't go as far as saying I really understand, more likely proving that a little knowledge is dangerous again :)  Trying to improve as we go (like a lot of folks, including a lot of the installers it seems!)

Thanks again,

Archibold

I never said it should be used as a temperature controller or a limiter or anything other than to resolve the issue of the Hive's calling for heat and not activating the heat pump.

I said you could move the main controller into the house but in 2 of the 3 heating modes (fixed flow temp and WC) it will only work the same as the Hive will as a temperature limiter.

If you want to use autoadapt mode then you would need the main controller in the house but we are now into too much detail for the OP's original issue.

The first time people post with an issue who are unfamiliar with how heat pumps function, they want a response they can understand, I was merely trying to keep the answer simple.

I do agree with your final sentence!  However...

If, as you say, the Hive isn't wired to the controller (do we actually know that?), and assuming that the heat pump switches on at least sometimes, then just wiring it in is unlikely to help so far as I can see.  Currently the presumption, based on the behaviour, is that the heat pump is set up to respond to its own controller (which is in the wrong place).  This means that (if the hive is disconnected) it is effectively behaving as if the Hive were permanently calling for heat (otherwise it would never switch on), and deciding what to do based on its own measurements.  If you wire the hive in, the behaviour unlikely to change unless the heat pump autodetects the third party on/off signal and uses this to override its own controller, or you also change some other setting on the heat pump to tell it to ignore its own controller and respond only to the hive.

If the hive is in fact connected then the explanation is exactly as suggested by OP, but obviously wiring it in has already been done.

Either way I cant see how 'wiring the hive in' can alone fix the problem.  

So to my way of thinking we need to go back to basics and set the heat pump up as its makers intended.  In many ways that's simpler to understand, ditch the hive and use the ecodan controller but relocated to the correct place!  Furthermore its what OP actually themselves suggested, which tends to imply that they understand it!

In short, and unless I have missed something, the simple answer to the question posed by OP is 'yes'.

I never said it should be used as a temperature controller or a limiter or anything other than to resolve the issue of the Hive's calling for heat and not activating the heat pump.

I said you could move the main controller into the house but in 2 of the 3 heating modes (fixed flow temp and WC) it will only work the same as the Hive will as a temperature limiter.

If you want to use autoadapt mode then you would need the main controller in the house but we are now into too much detail for the OP's original issue.

The first time people post with an issue who are unfamiliar with how heat pumps function, they want a response they can understand, I was merely trying to keep the answer simple.

So sounds like I need to move the controller inside (or get a wirless one and pair) and remove the hive, as a first step!

Follow-on question is that the kitchen diner has under-floor with a pump and was using a secondary hive thermostat to control.  Presumably I still need something that opens the manifold there and activates the pump?  It is not set-up as a secondary zone from the ASHP as that would have required a second distribution pipe from garage to house - IIRC, and it isn't that large a property.

Sorry for the silly questions, I'm learning as we go along here.

Thanks!

Archibold

Your Hive's should be telling the heat pump when to turn on and off as you are not using the Ecodan main controller as the thermostat as its not in the house. 

It really shouldn't!

Yes you could move the controller inside the house and use it as a thermostat but then you don't need the Hive's.

And you really should!

Most heat pumps should be controlled in most situations by their native controller.  The use of external controls other than as temperature limiters (but definitely not temperature controllers) is pretty much certain to reduce efficiency.

Mitsubishi wireless controller in auto adaptive mode is much more sophisticated. 

Indeed, and designed specifically to control a heat pump, with its particular characteristics, not a boiler which has very different characteristics.

Using the heat pumps native controller with properly adjusted weather compensation will ensure that the heat pump is on for long periods operating at a flow temperature which is as low as it can be to deliver the energy required to the house.  This massively improves efficiency (and comfort!).  This is fundamental to the thermodynamics of how they operate which is very different to a boiler.  Using an external thermostat/temperature controller will do the opposite.  There is possibly a place for simple external controls, but not as the main temperature controller.  The exception to this general statement is Homely, which is specifically designed to optimise some heat pumps. Whether Homely can do better than the sophisticated controller built into the Ecodan is an open question at present.  Quite probably not unless you use the tariff optimisation/look ahead functions which I believe require a subscription

Your Hive's should be telling the heat pump when to turn on and off as you are not using the Ecodan main controller as the thermostat as its not in the house. 

That's what it sounds like from your description.

Yes you could move the controller inside the house and use it as a thermostat but then you don't need the Hive's or just connect the Hive's to the Ecodan.

What is the house Hive connected to if its not connected to a heat source?