Vaillant Arotherm Plus Heat Pump VRC720 SensoCOMFORT Settings

[@hjalmarjohannessen3797]

Very informative video, and good Q&A’s Just got my Vaillant 10,5 started yesterday, here at Faroe Islands 🇫🇴

[@UpsideDownFork]

Thanks for the comment. Hope it's going well for you!

[@AnotherBoring43yearold]

Superb video! I’ve just had my ashp valiant installed with 250l tank and checked settings and all pretty much same as yours apart from some temps but that’s because screed is new and needs slowly heating i was told Only one change from eco to normal 🤞

[@joewentworth7856]

very helpful. one thing to be aware of is how the room target temp moves the heat curve. the heat curve graph is based on a room temp of 20 degrees, by setting 19 as your room temp this shifts the curve down almost 5 degree of flow. so having your room target at 17 your flow will be far lower than someone with 0.7 curve and room target of 20.

[@UpsideDownFork]

Yes, you're correct. I thought I had covered that in the video but apologies if I didn't. It wasn't a planned or scripted video, just a quick recording aimed at one member in the Facebook group who was struggling. Uploaded here too as thought it might help others on their journey.

[@joewentworth7856]

@@UpsideDownFork you seem to know it well. the curve can be tricky to understand. in the end you just want to lower it until its no longer keeping up with your house. enjoy the journey to better cops.

[@UpsideDownFork]

@@joewentworth7856 thanks for taking the time to comment!

[@terryrigden4860]

Most informative, thank you

[@UpsideDownFork]

You're welcome. I realise now that the video was a bit scatter brained as it was targeted at helping one individual that was struggling to find certain settings. I may record a more comprehensive and better thought out video going forward!

[@adrianbotos2819]

Hello. I recommend to use the Adaptive heat curve as Deactivated. This is under Instalation tab.

[@UpsideDownFork]

Thanks for raising that point. My adaptive heat curve is disabled 👍

[@MarkGaudie]

My adaptive heat curve was set to disabled on installation thankfully.

[@m23605]

Why?

[@UpsideDownFork]

@@m23605 It's only really applicable if you have the room temp mod set to expanded. If you have room temp mod set to inactive then Vaillant says that the Adaptive Heat Curve shouldn't interfere with your set curve. I think most of us disable the adaptive curve just to be sure we are in control!

[@m23605]

@@UpsideDownFork Thanks I'll have to look into what expanded means. This is for a rental so I want the system to look after itself. if it doesn't work, do you think I can make adjustments remotely? I've specced the internet gateway into the install job.

[@siekierkaKam]

Really appreciate you taking time to go through your settings mate. In my case im on diagram 8 schematics and my settings were not correctly setup by the installer. Thanks to your guide I adjusted mine. Could you please do me a favour and send me the link for schematics 8 diagram settings

[@UpsideDownFork]

@@siekierkaKam hello, it won't allow me to send a link here but you can either get it from the Vaillant Arotherm group, I've put it in the files section of the group there. If you struggle, email me at the channel email address and I'll send it back to you 👍

[@johnwestby3121]

Really useful video thanks. I dread to think how HPs will be set up when we eventually have a big uptake of them in UK ! My radiators warm up in the night when I have set DHW to come on with cheap electricity. Can I stop this happening please ? Thanks

[@UpsideDownFork]

I hope that a wide rollout will improve the education and implementation of commissioning these systems. No heat pump should be heating radiators and hot water at the same time. You should have a 3 way diverter valve that be default allows the heat pump to flow around the radiators and when that is energised it should stop all flow to the radiators and direct it through the coil in the hot water cylinder. If yours doesn't act like this, then you must contact your installer to have something corrected.

[@johnwestby3121]

Thanks for that. I shall be contacting the installer (Aira)

[@rolandrohde]

I actually have a bit of an issue with my Arotherm Plus 5.5KW unit...it appears to be incapable of providing a low enough flow temperature. When outdoor temps are above 0, it rarely manages to get the temps below 27-28 degrees which is of course more than I actually need. Seems even the smallest hwat pump (3.5KW unit is mostly identical) is somewhat oversized for our house.

[@UpsideDownFork]

Yes, that seems to be an issue. I've read about a few well insulated or smaller homes that suffer with this. Do you have the myVaillant app? Does it show you how many operating hours Vs cycles?

[@rolandrohde]

@@UpsideDownFork Yeah, it shows that I have 680 cycles in some 811 hours which is acceptable. I am trying to mitigate the cycling issue somewhat. My newest idea is using a Shelly Plus 1 connected to port S6 on the VR71 unit. This would turn the heating off (called externe Wärmebedarfsanforderung in German) when it has significantly overshot the desired room temp in the Bathroom. I will see how that affects things. Overall, it's not really a problem so far, but it is annoying that even one of the smallest Heat Pumps can't modulate well enough to always provide the appropriate flow temps for our building.

[@UpsideDownFork]

@@rolandrohde yes, for now the modulation ratios on these heat pumps appears to be 1:4 from what engineers say, hopefully they can improve that in the future and get closer to 1:10 and then heat pumps will work incredibly well under partial load. Good luck with your experiment! Although you don't have anything to worry about with less cycles than hours 👍 My buffer tank certainly helps the system in my house with reducing the cycling.

[@LookatBowen]

Interesting video, especially the first part regarding the heat settings, the heat curve, Min and Max flow temp. What did you mean by "use the TRVs as high limiters?" I have all my TRVs open at 5 (max). I have the room temp. mod set to Active, and my understanding of this is when the room temp. reaches the desired temp the boiler turns off. If inactive, what does it do when it reaches the desired temp? (I get the idea that is completely working off the temperature outside, and that was the reason I went for that solution, because I don't want to be mucking with the thermostat all the time. I have turned that option to Inactive to see what it does. Great video though, been searching high and low for answers, and you've answered quite a few questions I had.

[@UpsideDownFork]

Yes, inactive uses the outdoor temp sensor rather than the internal one. We find the internal temperature a LOT more stable by doing this, but you do have to ensure you get your heat curve right 👍

[@myatix1]

Would be interested in seeing an update on all your settings after having run your system for some time

[@UpsideDownFork]

Pretty much all the same. I've gone round and round trying to gain a little efficiency by tweaking to the max but what's shown here is pretty much perfect for my property. The only thing I need to actively be aware of is setting my DHW temp a bit higher in the winter and a bit cooler in the summer.

[@joewentworth7856]

With regards to the Vaillant 'working figure' AKA COP, it is a bit of an over estimate, from the wall controller live info, I could see the flow rate was ~800l per min and the compressor was off and it said the unit was using 0.00kw. So I suspect they don't measure the power used by the electronics or the circulation pump which makes the working figure higher than an independent monitor might suggest. still a useful metric to help you improve the performance but not a very accurate COP.

[@UpsideDownFork]

Thanks. That's a great point that Vaillant is very eager to make users aware of the fact that their figures are estimates. That said, there have been a handful of users who have fitted the whole open energy monitoring kit and they found that after a couple of months of monitoring, the figures estimated by Vaillant and measured by the openenergymonitor heat meter kit, was pretty much in the same ballpark. Ultimately like you say, a good baseline to work from when trying to optimise the system 👍

[@joewentworth7856]

@@UpsideDownFork I only say as i do not have independent measuring, and my working figure for the last year of use was 5.2 which although i have worked hard to get it as high as possible and the flow are only 40 degrees at -2. this figure is better than the data sheet suggest so maybe I just have a more inaccurate unit than those you are referring too.

[@UpsideDownFork]

@@joewentworth7856 have you considered combining your design temperature with degree days to calculate what your SCoP should have been according to the Vaillant specs?

[@joewentworth7856]

​@@UpsideDownFork that sounds interesting could you point me in the right direction to do this?

[@UpsideDownFork]

@@joewentworth7856 I haven't figured out the exact details but I am planning to do that once I have a bigger data sample, probably after a full year. I would like to present 1. My recorded consumption data according to Vaillant controls. 2. Estimated consumption based on MCS calculation formula 3. Theoretical consumption based on degree days, design temperature and extrapolating the flow temps based on my compensation curve. It should be theoretically possible and of course hopefully the 365 degree days are enough data points to level out over the year.

[@MarkGaudie]

My heat curve is set to 0.60 and so far so good really. COP of 3.6 so far for the year from Jan 2023 to date.

[@UpsideDownFork]

Thanks for contributing 👍

[@simonyapp]

Where is a COP displayed? Thanks

[@MikeGleesonazelectrics]

Very helpful video, thanks. Unfortunately a few weeks after my installation (same hp and controls) was set up I mistakenly reverted it back to factory default setting and lost all the commissioning setup! after some help from vaillant (the BG enguneer was most reluctant to return) I got it running reasonably well again but after yr vid I saw the curve was set on 1.2 so I changed it to 0.6. it now seems slightly warmer than before, good thing! One thing I noticed however is that my Target Flow temp is at 0C with no way of adjusting it. why would this be do you think? the min TF is set at 20c and the max at 46c. It seems to be working fine tho. Cheers..

[@UpsideDownFork]

Is your room mod set to inactive?

[@MikeGleesonazelectrics]

@@UpsideDownFork expanded I think..

[@UpsideDownFork]

@@MikeGleesonazelectrics So your pump will not be running on pure weather compensation. My guess is that your room temp is higher than your target temp and the sensocomfort has turned the pump off because of that. You will only find your true weather curve by turning it to inactive, but beware, any changes you make to the curve will take 24-48 hours to become clear.

[@MikeGleesonazelectrics]

@@UpsideDownFork Ok many thanks, I shall have a little play. The target Flow temp does come back on once its switched to inactive, as yours is but to me the target temp shouldnt read zero at any time at any setting but maybe its just me not understanding it..

[@UpsideDownFork]

@@MikeGleesonazelectrics Yes, it's a totally different approach once you set it to inactive. Low and slow, but you should see your CoP improve by doing that.

[@zalkhirsan9481]

That is such a useful video, even as CIBSE person I struggled with setting , what a about the max cylinder charging time and anti charging time ? You had it as 60 for each mine was 120 mins and 5 mins

[@UpsideDownFork]

@@zalkhirsan9481 it depends on your hot water strategy. Most of the time it won't take longer than 60 mins to reheat so it's possibly irrelevant above that number. The anti figure is how long after a cylinder reheat it will prevent the heat pump trying to do another reheat. Useful in the depths of winter if the building is cooling too much because it's diverting to DHW. If your DHW settings are good then those 2 numbers have little importance.

[@zalkhirsan9481]

That's superb 👌 thanks

[@Haik0]

This controls are so unintuitive and clunky, the naming of menus are so badly thought out. For how expensive and otherwise smart that device is, it would have been great to have it a bit slicker. Something like Nest or even Vissman controls are miles ahead of this potato. Thanks for clearing things out. Please do more of these videos, breaking down each menu. Appreciate it.

[@UpsideDownFork]

@@Haik0 I agree. Glad it could help 👍

[@lakshmikumar21]

Hi, in my case I have three zones, zone1 for radiators Zone2 again for radiators Zone3 for floor heating How do I set weekly planner? Do I need to set for zone1 and rest to manual? Or need to set the planner for all three zones Thank you in advance for your support

[@UpsideDownFork]

You need to set them for individual zones. For most efficiency you want the HP to be using as much volume as possible which means multiple zones open at a time, unless you have very large zones of Underfloor heating or radiators.

[@lakshmikumar21]

Thank you very much for your reply. What does multiple zones open at times mean? 😊

[@UpsideDownFork]

if you can, have the zones timed to match each other as much as possible. An open zone is one that is connected to the heat pump because the timers are showing that it is on. Good luck 👍​@@lakshmikumar21

[@lakshmikumar21]

Now I got it, really appreciate the time and advice . Thank you again

[@tomorshala4888]

Hi Sir, I have Valiant arotherm 155/6 S3. I learned a lot from this video. The company who set it up on my house didn't seem to have much of a clue how to set the best settings for energy saving. Current settings: 1. Weather is 7 degrees, and temperature was MIN 52 and MAX 55 set up by them. How low do you think it makes sense to lower it? 2. Curve is 60, and right now i just turn on the room modulation as it was off, and pump was running non stop and room temperature i had set up at 20 but always stays as 24. 3. I set it up also time asisstant programe. 4. DHW i set it up at 40 degrees with time programe as well I hope these would do the trick so I could get energy savings. Just looking forward to hear from you about min and max temperature for heating. I use radiators btw. Any further tips would be highly appreciated!

[@UpsideDownFork]

Start by lowering your min flow temp to 25 degrees. This should help a lot. Increase your DHW store temp to 45+ degrees and then you will not need to run the legionella cycle.

[@tomorshala4888]

@ thanks Sir. One more question, do you suggest that during night from 10pm to 6am to turn on time programme for DHW and Heating? Does this help on energy saving?

[@UpsideDownFork]

@tomorshala4888 this depends on your energy tariff and if you have a low cost rate overnight. It is always best to have the DHW heat just once per day. 👍

[@tomorshala4888]

@ lowering min temperature to 25 and other adjustments lowered the energy costs today by 40%. Only concern I have is that current room temperature is 20.5 while desired is at 21.5. I tried to increase heat curve from 0.7 to 0.80.

[@UpsideDownFork]

@@tomorshala4888 That's great that you've lowered your costs. This video gives the quick step by step approach to setting the heat curve correctly. It does involve patience and many days. kzbin.info/www/bejne/gaSYZnufZ7RrZ6s

[@barriedear5990]

Great video. Our 400l cylinder uses an external heat exchanger plate, rather than internal coil. The thermometer pocket is 40cm from the bottom of a 150cm tall cylinder. The cylinder water going into heat exchanger is drawn from the bottom of the cylinder, so presumably pretty cold. I tried lowering the cylinder charging offset to 5'C but it seems to remain at 10'C. Any thoughts?

[@UpsideDownFork]

This seems to appear frequently when the heat pump is overpowering the cylinder coil / heat exchanger. Vaillant flow rate is high to try and help this issue, but it just can't shed the energy quick enough.

[@barriedear5990]

@@UpsideDownFork Thanks. Will see what flow rates I can adjust.

[@nicolettacharolidi4203]

Thank you very much - this is the most helpful guide to the controller. I was searching for troubleshooting, as our water cylinder does not seem to be working, but no fault code is given. Any ideas? Thank you very much in advance!

[@UpsideDownFork]

Is this a new system or an existing system that has developed a fault?

[@edwardlamb]

This is really useful. Thanks! Can I ask how you've set it up in terms of timings for heating? I am on the 'Cozy' tariff with Octopus so heating outside of the peak time makes sense - but I'm wondering if I should just set it to keep the house at a steady 19C (with 17C set back overnight) and ignore the timer function. Thanks!

[@UpsideDownFork]

For me I can't make cosy work out as a cost effective tariff for our lifestyle. Ours is set at 20 degrees 5:30-8am and again at 3:30-9pm. Setback set to 17 degrees between those periods 👍

[@MikeGleesonazelectrics]

I think octopus recommends setting the heating slightly higher during the cheaper periods, so that the house is warmed up somewhat when it reverts to the peak period, so using less juice. I'm on the intelligent Go tarriff so I do that by setting the room temp to 22C for an hour 04.30 - 05.30am, when the off peak period ends (7.5p/kwh) , then setting it to come on again at 20C at 07.30am. This should cost less than heating from 6am say.

[@UpsideDownFork]

@@MikeGleesonazelectrics Unfortunately this just doesn't work with systems that are running true weather compensation because they will typically only warm up at a rate of 1-2 degrees per hour. Also, who wants to avoid cooking etc between 4 and 7pm. I know it's a different story if you have a decent home battery and inverter but I think the marketing and targeting towards heat pumps is misleading as for most people it will not work out cheaper because of how hard you will need to run the pump before and after the period to make up the difference.

[@MikeGleesonazelectrics]

@@UpsideDownFork I guess thats where different home situations arise.. in my case I have retained gas (reluctantly and for now) just for cooking as we have a full gas cooker. It also helps to heat the house for the evening in winter and is (at the moment) relatively cheap. Used just for cooking its cost £4.67 so far for the month incl standing charge. I do have solar pv and a small battery and now that elec prices gone/going up further I am about to replace/add to the battery with a larger one which is able to charge up for 6 hours @ 7.5p/unit. This is the ultimate and then prob can disconnect the gas completely. No wonder the take up of ASHP has been so low in the UK with the cheap cost of gas, its such an anomoly and needs to change. I should have held off for a bit, I only got the £5k grant!!

[@UpsideDownFork]

@@MikeGleesonazelectrics Yes, you raise many good points! Our gas is now gone and with it the £100 per year of standing charges. Our gas hob has now been removed but waiting for the Induction hob to be installed so right now we are in limbo and making use of the oven, slow cooker and microwave to get us by for a few days. I'll put together a whole video about getting rid of gas.

[@simongooden63]

Hi, thanks for all the videos! I have the same unit (although a 12kW unit) and same programmer. I was wondering if you had considered getting rid of your buffer to improve efficiency? I've spoken to Vaillant and know how to do it, however I'm worried about flow rate. Would be good to know your thoughts. Thanks

[@UpsideDownFork]

Hello Simon, thanks for your comment. Yes, i've covered this in some of my other videos. I'm monitoring my current performance throughout this winter and i'll decide what we do with the buffer later on. My preference would be not to entirely remove it but to re-pipe it as a volumiser on the return leg of the rad circuit. As my 7kW unit requires 20-55L for a defrost cycle (dependant on water temp), the buffer tank plumbed as a volumiser on the return would mean that it shouldn't initially draws heat from the radiators themselves during defrost. Your 12kW unit will require more volume for defrost I would imagine but you can check that in your manual. I don't believe there are any disadvantages to using as a volumiser. The theory that a buffer decreases operating efficiency is definitely based in science and engineering understanding but some of the claims of a 25% decrease seem somewhat exaggerated. There are so many variables when it comes to distortion that it could in reality only be a 5 or 10% decrease in efficiency. I've tried my best to match the flow rate on our rad circuit with the flow rate of the heat pump itself to minimise any distortion which will keep our efficiency as close to a non buffer system as possible. My most up to date running figures were just published a couple of days ago if you look on my channel.

[@simongooden63]

Hi, thanks for responding so quickly. Which video of yours covers this subject? The only downside to turning the buffer into a volumiser might be that you'd reduce you return temperature a little bit but I'd imagine that would be fairly minimal. My 12kW unit requires up to 150l but I have 11 large column rads and they add up to at least over 280l, plus I then have some underfloor. My worry with my system is whether the primary pump will work when I take the secondary one and buffer away. I was told by Vaillant that I need 2000l per hour, currently I'm only getting around 1500l. I'm not sure why and if this is really an issue. I was going to take away the pump on my UFH as well. Any thoughts? Also, how did you match the flow rate of your two pumps, are pumps easy enough to play with? Maybe as you said it's not worth all the fuss anyway. Thanks again

[@UpsideDownFork]

@@simongooden63 in your case with all that circuit volume it's probably not worthwhile to use a volumiser. I have 4 large radiators but the other 10 are all medium size, although I do have well over the minimum system volume, an extra 45 litres will only help the thermal mass and my pump will easily reach the 1200lpm it needs. I balanced my heating circuit pump to the heat pump itself by setting the heat pump to a fixed flow temp and measuring the DT across the flow and return. I then measured the DT on my heating circuit which was much smaller as left by the installer. Dropping the constant curve on my grundfos pump from 3 to 2, got it to almost match within 1 degree. Once I put it back onto full weather compensation, the DT between the HP side and the rad circuit side remained pretty closely matched as I monitored those temps for about a week at various times. Ultimately, it will never be a perfect match unless the heat pump could control the heating circuit pump modulation. I'm sure the real experts will also factor in the balancing of rads to achieve the correct DT on the rad circuit side. I did measure all of them and got them.all pretty close after a few days of back and forth. A clamp thermometer or at a push an IR thermometer are your best friend if you want to monitor and/or tweak 👍

[@simongooden63]

​@@UpsideDownFork thanks again for your help. One last set of questions... I've bought a clamp thermometer as you suggested but I see there is a temp probe on my primary return, do you know if this temp can be found in the SensoCOMFORT settings? I can only find the flow temp, not the return. Secondly, in regards to balancing the rads, do you mean you measured the flow and return temp at each rad and adjusted the lock-shield valve to get the same flow and return temps for each rad across the circuit?

[@UpsideDownFork]

@simongooden63 Return temp isn't in sensocomfort, but in the main controller. I ignored those temps for my measuring so that the same meter was used for both and don't have to worry about calibration. Yes, the rad balancing was measuring the flow and return across all radiators. Once those are correct then I measured all the ambient room temps and had to go back and adjust a couple of lockshields to try and get the right balance between room temp and DT across rads. Hope that makes sense.​@@simongooden63

[@AnotherBoring43yearold]

Can I ask, my new valiant ashp was done this week and it’s only got an outside thermometer and the hub temp sensor is off How does it know all the room temperatures? Do you monitor each room individually and if so how? Just all new to me and would love to learn more

[@UpsideDownFork]

I use these in the rooms to roughly monitor room temp. amzn.to/3TMyaJ8 You can pay more for Bluetooth or data logging thermometers if you want. I started with getting the heat curve set correctly to heat our living room which is the coldest in the house and then worked backwards from there. If necessary, adjust the room TRVs to limit overheating in some of the other rooms, especially if you often leave doors closed. I found that because the heat pump is pretty gentle in the way it heats that the rooms and the house were naturally quite well balanced and I didn't need much intervention, especially once I lowered the heat curve to where it should be. The old gas boiler was many times worse with hot and cold spots all over the house.

[@AnotherBoring43yearold]

@@UpsideDownFork thanks! I’ll look into those monitors Good idea to work backwards from coldest room We’ve just extended the house and had the task of insulating every internal wall which was fun We have solar, Tesla pw , two evs and now ashp so need to see if octopus offer a better option to octopus go that we are on Gives us 5 hours off peak at 8.5p and I like that it’s simple and we never use peak so that’s nice Can’t get intelligent yet as cars aren’t compatible and smart Hypervolt isn’t yet either Thanks again

[@UpsideDownFork]

@@AnotherBoring43yearold The best tariff will likely be directly linked to how many miles you do in the EV, unless you're happy to switch at least once a year. With your PW, you will probably be best served by the Cosy tariff when it gets really cold and the heat pump is consuming a lot of energy. But then again if you do a lot of miles in the EVs every day then you may be best sticking with Go and just trying to load shift as much as you can to the cheap energy window. Good luck, I quite enjoy the game of tariff hopping! Consider trying the Octopus Compare app as well. It will take your smart meter data and show you how much it would cost on various tariffs. Difficult for you to get a perfect picture because it will be influenced by the load shifting.

[@marcuscooper9544]

Hmmm... my unit doesn't have the option to turn off or edit the Anti-legio settings.

[@UpsideDownFork]

That is very strange!

[@daydreamstar1707]

Has this model increased your gas/energy bill? Compared to what the sensoHOME control panel would cost to run.

[@UpsideDownFork]

The panels themselves will not change your running costs, but the settings will 👍

[@NJT-TWRV]

Hi, Could you let us know the model of the VRC720 you are using, there are at least 6 variants, each with it's own nuances particularly in the Help (?) function. It will be something like VRC720X/Y Where x is either F or blank and Y = 1,2 or 3. Cheers

[@UpsideDownFork]

Hello, this one is the VRC720f/2. I didn't touch on that in the video as the core functionality is the same across the models and the biggest difference that end users will notice is if their system is not schematic 10. They will likely have additional options that mine does not show if that's the case. Thanks for taking the time to comment 😊

[@luk5827]

The target flow temperature can be lower than 30C also ? So , if you want to command just with wheather compensation sensor , without inside room temperatur , than you need to disable adaptive heating curve ?

[@UpsideDownFork]

Yes, the flow temperature can go lower than 30 degrees. Adaptive heating curve may automatically be disabled when you select room. Temp mod. Inactive, but it's good to disable it if you want full control 👍

[@luk5827]

@@UpsideDownFork If i'll use gas boiler ecoTEC than i'll can setup the calculated by heat curve target flow temperature lower than 30C ?

[@borjacasbas1887]

room temperature inactive is more efficient that expanded? thanks!

[@UpsideDownFork]

Different approaches for different homes but inactive will give you more consistent heat throughout the whole home as it's not susceptible to solar or other heat gains in the room where the sensocomfort is placed.

[@MarkGaudie]

My cylinder charging offset is also set to 10k

[@UpsideDownFork]

Good, sounds like your commissioning was done properly.

[@what-lies-in-your-skies]

Is it cheaper to have the system on manual or on a timed setting? Im in a newbuild. Aaron services came out and changed it from auto to manual settings. My temperature is set at 17°c

[@UpsideDownFork]

That depends on lots of factors, but manual is not the right solution for most people, most of the time. 1. What is your lifestyle? Are you mostly home or mostly out? 2. How well insulated is your home? Being a newbuild it should in theory be quite good. Rule of thumb: - If you are away most of the day time for work, then use the timed setting with a 2 degree setback. - If you work from home then leave it at a constant temp all day long but you still really want a 2 degree setback at night as it is better for our bodies to sleep in a slightly cooler temp.

[@what-lies-in-your-skies]

@UpsideDownFork thank you for your help, the engineer advised how he set it up is most effective 🤷‍♂️ we're home most of the time, it was set on 18 on timed and setback was 16. I changed it to 17- 15 set back. I asked him which is cost effective, not sure if having it on constant or having a set back, not sure if costs more for it to climb back up the 2° once the morning comes. I just hear the fan on on a night and hoping it doesn't cost a fortune.

[@UpsideDownFork]

@@what-lies-in-your-skies In terms of running efficiency (CoP), it is probably better to leave the same temperature 24/7 but in terms of running costs, a 2 degree setback will definitely work out cheaper to run on a standard electricity tariff. If you have a cheaper night rate then it's a totally different story.

[@MarkGaudie]

In terms of heating my hot water cylinder I only run it at night on cheap night rate

[@UpsideDownFork]

That's the way to do it 👍

[@swedishkev]

Hello again, I have heated floors, now it's minus 19 here in Sweden. My heat curve is on 0.70 I noticed tonight that my rum temperature has gone down from 22 ish to to 20. So this means that the system is struggling to keep right temperature. Flow temp is about 39 degrees.. Any ideas,do you think it's just understandable that it's struggling a bit with this cold here. House is well insulated. 3 glass windows. 4 bedroom ,2 floor house. System is split75/5 think it is a 7,5kw system.

[@UpsideDownFork]

Hello there, do you know what your design temperature is? Was the UFH installed at the same time as the heat pump?

[@swedishkev]

@@UpsideDownFork UFH? What is this ?

[@UpsideDownFork]

@@swedishkev under floor heating.

[@swedishkev]

@@UpsideDownFork no this is a new pump install 4 months ago. I still have lots of air noises in the system though. Before was a sanyo eco from new 2008. Never ever had all these noises in the pipes. Obviously, it will not run to the best efficency. I am going to get this looked at soon. But this does not have so much to do with why system was struggling at minus 19.

[@UpsideDownFork]

@@swedishkev I would make sure that the flow rate is set correctly according to the spec of your underfloor heating pipework/manifolds and of course the Vaillant heat pump itself. Flow rate is critical. 👍

[@swedishkev]

Hello mate, l see that you had a room temp on 17 and you got 19 degrees. ?I have all floor heat on the 2 floors,and you have radiators. I normally have 22 downstairs and some rooms are at 21 or 20 upstairs. Dont know if there is much difference. by the way have the 75/5 split system. Water and air. Sensor atsode by the fan and l think there is an indoor sensor in the 720 wall unit.I am in Sweden and a week ago it went down to minus 17 and then I suddenly only had 20 down stairs and 19 upstairs. Would of thought ,the system should of coped better. All was checked and no faults. My heat curve is on 0.6 this means nothing to me ,have no clue if it should be higher or lower. Its not so cold at the moment and only minus 5. Max flow temp,l think is on 38 degrees. but in app seen it up tp 55.. Also when l look at the blue screen on the pump its says 48kws, any idea what that is saying. I am only using on average 26kws per day according to the senso app. I really have not much idea what any of this all means. By the way one zone all on manual and l don't have heating coming on at different times either.

[@UpsideDownFork]

Hello, I can't advise you on your system I'm afraid but in the video the actual temperature is higher than the target temperature because it is just going onto the setback And i had also taken the controller into my home office to make this quick video. My home office has large south facing windows so regularly experiences some solar gain throughout the day. Take care!

[@swedishkev]

@@UpsideDownFork thanks,l only wanted to understand,heat curve and flow rate, and if you had any thoughts on why my system was slow at keepingcthe heat,when it got to minus 17. You seemed very knowledgeable.

[@UpsideDownFork]

​@@swedishkev the website energy stats UK has a good section about the compensation curve that might help.

[@ismailmyzyri7131]

Hello, Can this controller replace my VRC 470/4 for my Vaillant Aerotherm HVAC?

[@UpsideDownFork]

You'll have to ask Vaillant technical about that, I'm not familiar with your unit I'm afraid.

[@Noname4now2025]

Can be used only on vaillant heatpomp?

[@UpsideDownFork]

Yes, this is only a Vaillant controller.

[@MarkGaudie]

I run my hot water up to 50 degrees. Once a week a run legionnaires cycle to 60 degrees.

[@UpsideDownFork]

Yes, this is recommended but based on my personal risk assessment, it's unnecessary for us.

[@MarkGaudie]

@@UpsideDownForkI honestly don’t think I need the legionnaires cycle as we use up most of the water everyday with bathing the kids and showering etc.

[@UpsideDownFork]

@@MarkGaudie That's the exact reason for us too.

[@kiwim3p587]

Just a word of warning, flushing the tank every day doesn't eliminate the risk of legioneers, it lives in the biofilm and sludge in the bottom of your tank, strongly recommended to steralize the tank at least once a week.

[@nevenkofilipek]

19.5 temperature.... dont be ridiculous, you have literally cold house.

[@UpsideDownFork]

Haha, mate, you should do some exercise and improve your circulation if 19.5 degrees feels cold to you. 19.5 degrees is shorts and t-short temps for the young and healthy.

[@nevenkofilipek]

@@UpsideDownFork Below 21 is for me not comfortable in my house because outside is 0

[@mkkd85]

Anything below 23 feels cold during the winter (young and healthy folks here).

[@UpsideDownFork]

@@mkkd85 Where are you people living? Southern California?!

[@siekierkaKam]

19.5 with central floor heating everywhere is enough in my house with 2 floors. If I set it to 20.5 it becomes impossible to do anything inside as I literally sweat like crazy