Posted by: @craigh

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installers were more than pathetic, I've still got air in my radiators now after bleeding them many times and also I had to sort the external pipe insulation out as there was great big holes by the valves and the joints weren't sealed properly, I don't want the installers anywhere near my house though.

Sounds like my installation…

I found the manual for the Dixell controller only on a retailer website for MKM Building Supplies. 

This should have been easier to find from Daikin.

It’s essential that you check the set point on that controller as it controls when your secondary pump kicks in and I found the factory setting way too high at 37degC.

(press the set button)

The effect is that the heat pump starts up by only warming the buffer tank. With no heat being lost to the radiator circuit it overshoots its target flow temperature and shuts down. This happens repeatedly until the buffer tank reaches the set point temperature. Only then does the water start circulating through the radiators and the system have some chance of achieving a steady heat transfer to the house. 

I have mine set to 25degC so that I get water flowing in the radiators as soon as possible after the heat pump is starting up. This has effectively eliminated start up cycling.

(press and hold set and adjust with arrows when the display is blinking; press set again to save)

Also, the Madoka is not just a dumb thermostat. It supports modulation and allows you to get the best of the efficiency from LWT control whilst allowing some real world feedback. It can go slightly above or below the weather curve to account for temporary changes to the heat loss e.g. solar gain or someone leaves a door open for too long.

If it wasn’t for DHW and the occasional defrosting, this keeps my pump running permanently in winter and maintains a comfortable temperature.

I hope that helps.

Morning @majordennisbloodnok 

Can I ask your take on the smart+ subscription? @toodles has given me a really good insight into the homely system but he's recommended to ask your advice on whether the subscription is worth doing and it maybe pays for itself?

You gave me some great advice a few weeks ago on another subject, you were a bit worried you'd waffled on😴, but your advice were spot on thank you and at a level I could understand clearly.👍

I'm past the point of trying to sort the efficiency manually so getting a homely installed seems a great idea after reading a lot of posts on this website, I've got the hub pack and the d-com units on it's way, I'm not an electrician but certainly capable of having a go at installing it all in a safe manner if pointed in the right direction, as I mentioned to Toodles the installation manuals not the clearest, I'd like to know how to power the d-com unit and can I buy the cabling at somewhere like Screwfix mainly but any advice on the the whole install is greatly appreciated. 

Thank you 

Regards 

Craig 

@craigh Hello again, I meant to indicate that @majordennisbloodnok uses automation and that I think, uses the Agile tariff. What I was trying to suggest was the Major may be able to provide a comparison and whether the Agile tariff still works out cheaper for his uses than Cosy might. All these comparisons are very difficult though as every variable complicates any comparison. Times of demand, storage capability, willingness to apply attention to automation or manual faffing etc., is there an EV in the equation and so on. Regards, Toodles.

@craigh, @toodles, sorry for the delay in responding.

Yes I do use Octopus Agile incoming and yes I do automate stuff with Home Assistant. I also have tried Agile outgoing although I’m just on their standard variable Outgoing at the moment.

I can’t comment on whether or not Cosy would be better or worse for us since we have a relatively small battery (6.5 kWh). The really cheap off peak rates for Cosy, Flux and Go tend to be at their most beneficial when you can store enough power to tide you over the relatively long peak price times whereas Agile only tends to have two relatively short peaks - the main one being 4pm-7pm. In addition, none of the other tariffs ever get negative pricing which, whilst rare, can and does happen with Agile.

Our usage patterns are all over the place so the regularity of the other ToU tariffs isn’t ideal for us and Agile combined with rules for exploiting time shifting, opportunistic pricing and saving sessions is a much better fit. However, in order to make Agile work for you, you really do need to get away from set scheduling or manual tinkering and that’s not for everyone.

As for Homely, Havenwise and the like, the main thing they can do over and above ensuring you’re running on weather compensation is to overheat your home at times of cheap energy and throttle back when leccy is expensive. In effect, it’s turning your home into a heat battery and that can certainly increase your savings a bit. However, the tradeoff is that you have to accept wider temperature swings and that’s something my wife and I don’t like.

@djp01 you've done well finding anything out about that Dixell unit. Lol. Daikin and even the manufacturers of mine heat world couldn't tell me how to set it up, what a contraption to put on a heat pump. By the sounds of it it needs to be set up at different target temperatures at different times of the year, there'll be a lot of people out there unaware of this I would of thought. If you press set+down at the same time you can go into the settings (if you dare) as theres a few tweaks you can try, just take pics or something of your original settings. The 1st one that comes up is hy(hysteresis), you can trial bumping that up a bit to stop the secondary pump starting and stopping every 2 mins if that's happening, AC(anti short cycle) increasing that valve forces the compressor to rest for longer, you can also set an offset if you think your buffer temp calibration is different to the heap pumps but I'm not sure what on this one but its called Ot on the menu. I'm by far no expert though, I've just been dropped in it and spent hours and hours trying to find stuff out. I didn't have a moments hassle with my 13 year old baxi boiler, it just did its thing and I did mine, I'm praying @toodles knows his stuff and the Homely system can save me from spending the foreseeable in a straitjacket, I wouldn't mind but I much prefer being cool, the missus is loving all this heat 24/7 heat though, 19.5⁰c seems even her limit though so how you do 22.5⁰c @toodles I'll never know. Lol. Thank you @majordennisbloodnok for your reply too, always good to get your take when you need some top notch advice. Thanks everybody. 

Craig 

@craigh I refer to our somewhat elevated temperature of 22.5 deg. C as our ‘comfort level’ for good reason; this is the temperature at which both of us are comfortable.

This I think is the result of medical conditions and possibly to a certain extent, our *ages. Though speaking for myself alone, come the summer when we will probably have the global warming ‘Phew, what a Scorcher’ weather again, I will be quite comfortable as I don’t seem to have any problems. My wife finds it a bit on the warm side though, however, we have blinds on all windows; the ability to shut them on the sunny aspects of the house and change these later in the day as the big yellow thing swings round to the south and then west. We manage to keep the house cool enough with judicious use of some fans.😉

*As a youngster, I was happy with 19-20 degrees and when working in precision engineering, this was just as well as all measurements are supposed to be made at 20 deg. C. anyway. Regards, Toodles.