@davidm06 I changed 2141 to 2 last night but it seemed to cause it to short cycle so I've moved it to 4 and it's been jogging along quite happily at 26 LWT using about 600w with no cycling so it seems to like that setting

I have 2141 set to 2deg all winter now and it’s working well, I have underfloor heating so the temperature loss is slow so 2deg works for my house and it compressor doesn’t cycle that often. I have the LWT set to 23 at outside temp of  +15 and 33 at outside temp of -4, my house is air tight and has lots of insulation so that curve works for us, took a month or so to get it right, every home is different. I’m really happy with it now, house is warm all the time and consumption is low, about 600w at outside temp of +5 and 300w at +10, the most I’ve seen it use was 1700w when outside was -2, but that’s fairly rare here on the south coast of Ireland.

@damonc interesting! It all depends on your house I reckon. If your insulation is not wonderful as ours isn't, 2C might be reached too quickly and if it short cycles it might not be great for the parts. I might also try 4C and watch the effect on our daily usage. Every house will be unique.

@davidm06 no doubt you're right, the house is newish and well insulated, maybe it's the volume of water and with it set at 2 it reaches target temp very quickly then goes in to cruise mode but the volume means it drops back 2 in a short space of time (this is at about 2 OAT) and the target LWT is about 27

Thank you all so much for the information in this thread, we have just had the nightmare install from hell of a Grant Aerona3 13Kw (hence the username) on the ECO4 scheme which we are still getting to grips with. The info in this thread has been great to give me the confidence that the settings we have are a good start point to tweak the system going forward. The image below is just a teaser of the hatchet job these cowboys have done, but that is for a different post! As for the original question of if the controller is a thermostat I believe it is, we have the ridiculously comedic EPH CP04 controls with the RF remote thermostat (they couldn’t even install the CP04i the cheapskates!). The remote thermostat is reading 19c but the system is seeing 23c which I believe is coming from the actual controller in the nice toasty warm cupboard with the tank in (which we lovingly refer to as the “plant room!”).

As the controls are so woefully unintuitive I have connected a Wavesure Modbus to ethernet adapter to my Home Assistant server and now get real time data from the heat pump to hopefully make it easier to tweak the system (Happy to share my adventure getting this set up with anyone interested).

Once again though thanks again to everyone for helping me get this far!

Si.

thanks to @davidm06 and @bajj but still not resolved the short cycling I'm seeing although really it's short running rather than short cycling it's probably running a full cycle every 25 minutes but of that about 5/6 minutes it's running raising the flow temperature to 29 It'll hold it there for a minute or so and then switch to circulating allowing the flow temperature to drop back over the next fifteen minutes to 25, which I assume represents the hysteresis difference. I've got UFH and radiators upstairs. It's 3° outside. I don't see any ice on the fins. I don't think it's defrosting. I don't really understand why it's not just running constantly and maintaining the 29° flow temperature. Maybe I should set the hysteresis to 0.5° but that's well away from the default and so feels unwise. Could it be anything to do with the frost protection settings grateful for any thoughts from the group.

@grantmethestrength I'd be interested to hear more about your Wavesure Modbus to ethernet adapter install. I can provide my email if you don't want to post.

Posted by: @grantmethestrength

↑

The remote thermostat is reading 19c but the system is seeing 23c which I believe is coming from the actual controller

The system should not be seeing the 23C, in fact it does not see / use any internal temps any more, it is just showing the current temp. The reading on the EPH is the temp it is trying to reach.

Grant, like other manufacturers, use other manufacturers HP and rebadge it. It allowed two controllers, one master one slave. Master was normally in plant room, slave in the lounge and it was this that controlled the HP. 

After a short while they dropped using these controller to schedule the heating etc and switched to other controllers (EPH etc), but they did not remove them completely as they now use them to set up insulation. So it still shows the IAT and OAT. You can actually use this controller if you want to run the HP, but the user interface / settings are old hat now and things move on.

They have now come out with another controller for the R290, but it can be retro fitted to the R32 and thus (I believe) remove the controller attached to the HP

Posted by: @davidm06

↑

@grantmethestrength I'd be interested to hear more about your Wavesure Modbus to ethernet adapter install. I can provide my email if you don't want to post.

Add me to that list

@uk_pete_2000 Sorry I should have explained better that is the reading off the modbus register 33 “indoor temperature master actual” which I think is an inbuilt thermometer in the controller that is in our “plant room”. It is totally separate from the RF controller temp and as I have since found out isn’t affecting any tinkering I am doing.

I have gone over the broad strokes of the modbus integration ina response on another thread. More than happy to share my experience further.

Regards

Si.

@davidm06 a bit more detail here.