@hcas The biggest individual feature to be checked to ensure that the ASHP runs efficiently is to ensure the unit is set to Weather Compensation. The second thing is that the Leaving Water Temperature has not been set on the installer’s favourite setting of 50 degrees C.! A starting point of 35 degrees might be set and work from there. Regards, Toodles.

@hcas hi hcas, I’m very pleased with my Altherma 3H HT. over the winter period (Oct 28th to March 25th) we used 3140kWh of electricity which produced 13024kWh heat for a SCOP of 4.15. I estimated this cost me £695 on Octopus Go. With gas at 6p/kWh and a 90% efficient boiler, that would have cost £781. All good. 
I think the efficiency comes from running in weather compensation mode & only heating h/w at night on low tariff, when the ASHP isn’t heating the home. I.e. system doesn’t keep switching between heat & h/w. 
System was annual serviced today. All good. Waiting for formal report. 
Can have a video call if that works. I am thinking of doing an open house via visitaheatpump.com - if I can persuade my wife at allow strangers in.

@julianc Hi JulianC, I'll DM you and we can perhaps set up a brief call like you suggested!

@hcas I'll be the first to admit I'm a complete novice when it comes to ASHPs, anything I've tried on my own I've learned from reading hours and hours of these kind of forums so I'm not sure how helpful I can be but I'll give a brief run through of my setup.

I'll start with the am I happy with how it's running, over all I would say yes I am happy with the system and how it runs. But, I am not impressed with the level of after sales service or tech support that Daikin or their sales partners offer here in Ireland, I've found it quiet poor. They never really shared any info on how to run the system or how best to set it up, any issues or questions I've had that I called them on they didn't seem to want to know about them. They also ONLY offer a 36 month parts warranty and 12months labour warranty.

That's what led me to this forum(and others). I'm in a new build house since April 2023 that I over spec'd with insulation and went with triple glazing so I benefit greatly from solar gain. I didn't however go with full air tightness or MHRV, I have humidity controlled wall vents in each room.

I had been running my space heating with individual room stats calling for heat, or not, and with a fixed LWT of 34degrees and found that it worked well and was happy with performance, but I knew no different on how to run it at the time.

Since I stumbled upon this forum in late January I have been toying around with Weather Compensation on my Space Heating and trying to get it set up. I had just about got it to where I want it (I think) before the outside temp started getting a bit warmer. I currently have it set at 34d LWT at -2 outside temp and 25d LWT at 18 outside temp but the individual stats are still controlling each zone. That is as far as I can go on that for the minute though as I think I'm at the wrong time of year to get a true setup on the weather compensation, my space heating hasn't called for heat for nearly 2 weeks now so I may wait until next winter to get a true setup on WC. I do plan on running it like some have suggested on this forum though with the rooms calling at 2 degrees more than desired to keep the unit running longer at lower temps. Having done 1 winter at fixed LWT I'll have a comparison to work off of next year. 

I run my DHW on schedule + reheat. I set it to 50degrees schedule set point and 48degrees reheat set point with a hysteresis of 4degrees. For us I find this works best as there is constant comfortable hot water and when it does need to re heat it's only topping up a few degrees so not running excessively, I also find that tank holds the heat quiet well, my DHW cycle only really runs after one of us has a shower. I am pretty happy with what it was costing, between 1st April 2023 and 31st March this year my total electricity cost was 2,240€uro, but that's everything, heating, lights, cooking, hot water, etc.(No other energy bills)

One issue that I have found is that the LWT and RWT are nearly always the same on Space Heating even though I have a delta T of 5 set and this sometimes causes short cycling when smaller zones call for heat. I was blaming flow rates but I have those pretty much bang on now I think. The possible cause in my opinion is where Daikin have positioned the RWT sensor, they have it after the Space Heating bypass valve, I think it should be positioned before this valve on the return line from the manifolds as that is where the true RWT will be and should taken from this point. I'm going to source a PT100 and test my theory at some stage before next winter to see if it resolves the short cycling.

I know the above is not overly technical and there is far more knowledgeable guys on this site but it's as good as I can give for now. I'm hoping by the time next winter is over that I could confidently say I know about running a Daikin ASHP.

Best of luck with yours

@crasher that’s interesting. One of the reasons I chose Daikin was because of the 10 year fixed price service, warranty & parts. I’ve found the support to be ok. They faffed a bit first couple of years booking the service. But this year I was called to agree a date. Early on I chatted to their technical help line. I’m in UK.

@julianc I went investigating after I saw you mention a 10 year warranty, they don't seem to offer it over this side of the water. The best I could get was 36 month parts and 12 month labour that I got when I bought the unit, my labour warranty has now expired. To keep the parts warranty active I have to get it serviced annually by a specified partner of Daikin at a cost of €250 each time so I'm essentially paying €750 for a parts warranty. A lot of their tech support and servicing seems to be run through service partners as opposed to Daikin themselves as well.

@crasher

I hope you realise that a PT100 is only a sensor and will require a suitable indicator to read the actual temperature.

@crasher Hmm that is expensive

@derek-m I do, I'm an electrician by trade working in maintenance so have the means to test my theory 🙂

@crasher Thanks for this detailed explanation! Are you using the Onecta app or controlling everything through the MMI and the thermostats?

@hcas My unit wasn't supplied with a wifi adaptor card so everything is through MMI and thermostats for now.

I never really felt the need for using the app to be honest, most likely because I didn't know enough about my system and when running at fixed LWT it just ran and I wasn't overly concerned with performance so wasn't looking into things as much as I probably should have been. But since I've started trying to learn more about its performance and become more interested in what I can actually get out of it I think the wifi adaptor card will be a purchased shortly and the app makes sense to be using.

@crasher If you're happy with the controls provided through MMI and associated running cost, and you don't want remote control or additional "smartness", there is limited benefit in adding Wifi.

However, once you add Wifi, you could do some cool things with your heat pump and go beyond weather compensation, like using predictive controls. I've written some scripts for this - happy to tell you more about it if you're curious!