Posted by: @batpred

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I had the impression that any Heat pump type of cylinders would be compatible with any heatpump...

Generally yes although some heat pump manufacturers recommend specific ones.

There is no fundamental thermodynamic reason why a heat pump that will go to 75C (which R290 pumps do) shouldn't be used with a non heat pump cylinder with a typical 0.6sq m coil, albeit efficiency will be lower (but the business case for replacing a perfectly good cylinder is unlikely to pay back in short time!).  However there apparently some issues with the flow temp algorithm which can cause problems with some heat pumps, particularly larger capacity ones. 

This whole 'heat pump cylinder' thing is in essence a hang over from older refrigerants which couldn't reach sufficiently high flow temperature, it is really time that it went away and became an efficiency/reheat time consideration not a 'must do'.  In fact I believe Heat Geek now do not replace cylinders by default.

For some while Vaillants own 'heat pump' cylinders have had a coil that is smaller than the 3sq m normally specified.  Maybe Vaillant have tweaked the FT algorithm further in their new model and so can now comfortably specify even smaller coil sizes.    

That makes sense. If the heat transfer into a cylinder is better, the pump can be run at a lower FT, helping efficiency. 

In our case, the heat geek calculator was generally providing a low guaranteed scop around 3.5. Potentially this is why it was excluding Vaillant tanks when in combination with the Pro 🤔. 

We are currently having our Arotherm Pro 7kw installed, with all wired options. The pro version of the 75 model is a bit more compact than the new plus, only heats to 70C, has some space saving  options (that we do not need) but probably very much the same. 

Very happy with the installers so far.. Any suggestions of what to check for? Since the system will go live while it cannot be put through real testing for heating.. 

One of the test modes in the installer menu forces it to heat the house.  Make sure your installer uses it!

Other than that just the usual checks described many times on this forum which I think you have been following pretty diligently.

Posted by: @jamespa

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One of the test modes in the installer menu forces it to heat the house.  Make sure your installer uses it!

 

when our system was installed in September 2 years ago the house was already 25C inside. So with the heating mode set to target 35C the windows were wide open (it was less than 35 outside) and the guy was dripping wet and trying to balance very hot radiators. I felt for him!

@judith @jamespa 

Our installer used screed drying mode. I think that does not deliver heating to the house. Appreciated since in this case, it would be all of us sweating.. 

They made all the reasonable checks and we know how to get to the right heat curve, been through all teh configs in the menus, etc, so happy with it.

We have a free visit included when we decide it is cold enough etc. just if we want it (for rad adjustments etc), I doubt we will need it. 

They will also monitor the system remotely through the gateway. 

Cooling function still not enabled but looking forward to it..

Posted by: @jamespa

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Other than that just the usual checks described many times on this forum which I think you have been following pretty diligently.

I had some AI assistance to put together a checklist, did the trick. It was a very smooth installation. They installed the Hager type consumer unit, etc. 

The only thing that I have not yet figured out is the best way to restart it (the Pro) so it does not throw a number of error codes in the process.

I was told to first power up the controls and then the pump itself. With that dedicated Hager CU, it would seem hitting the big red button (like if power would come back after an outage) would be a safe bet...  

Posted by: @batpred

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I was told to first power up the controls and then the pump itself. With that dedicated Hager CU, it would seem hitting the big red button (like if power would come back after an outage) would be a safe bet...  

 

I was told to do it the other way round, albeit for the plus.  Hey ho.

Posted by: @jamespa

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Posted by: @batpred

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I was told to first power up the controls and then the pump itself. With that dedicated Hager CU, it would seem hitting the big red button (like if power would come back after an outage) would be a safe bet...  

I was told to do it the other way round, albeit for the plus.  Hey ho.

It kind of should not matter... My main thought is to avoid spurious warnings..

But given that ModBus is in use here on the new Arotherms, I am wondering if anything changed..

So with the dedicated Hager CU, flipping the big red button to bring both pump and controls simultaneously back up avoids spurious fault codes!