Benpointer

Doh! Yes should've done that! 🤦‍♂️ Anyway, there wasn't much above 55C in the top of the tank; I duly dumped it. And hey presto the ASHP ran consistently at 3.5 kW draw for 20 mins without a problem heating the water. I did notice some build up of frost on the back of the ASHP but to be expected, I guess. Seem to prove the issue is not with the ASHP itself. So... On further investigation there is a mixer valve on the UFH heating circuit (photo below), presumably to ensure the flow to the floor is not too hot. It was set to MIN. (When? Did I do that in the summer to 'save money' - I don't remember doing so). I have now set mixer valve to MAX and the ASHP has been running uninterrupted since(!), showing 41C target and 41C actual flow temp. So that's progress. I'm not totally out of the woods yet though as the ASHP is still only drawing about 1.0 kW. My assumption at this point is that there is a flow issue with the UFH that prevents the 41C water getting to the floors at a sufficiently high rate, thus the ASHP is not having to work very hard to keep the UFH water at 41C. Not quite sure the where to go next. There's a Boiler Buddy which has never been cleaned to my knowledge so that may be worth looking at (albeit, it's on the ASHP circuit so would affect both UFH an DHW if that was the issue). There's a dedicated pump for the UFH circuits but if that had failed, I assume we'd have no heating at all. The lad the plumbing firm sent round was not much use btw - scratched his head then called his boss, who suggested the ASHP might need re-gassing (why?) Photo of the UFH mixer valve, now set to MAX:

I am going to try to see if I can get the ASHP to run without interruption in Hot Water mode, rather than UFH, in an attempt to rule out blockages in the UFH circuit. Normally we don't use the ASHP for HW because, reasons, but it is connected for HW. (We use solar HW and an immersion for HW). Just need to persuade Mrs. P. it's ok to dump 100l of 65C water to get the thermostat to trigger ASHP HW heating (!)

Well I think so but I am not sure how I would tell for sure? There appear to be two circulation pumps, one on the out and one on the return. I do have a plumber coming out to look at the issue tomorrow but he is not an ASHP expert - I am hoping he will either give the UFH a clean bill of health or spot and resolve the issue. Again, I am not sure how to tell for certain. The side and back look frosty for sure but not, as far as I can tell, full of ice. Here are a couple of photos: (Thanks for the replies btw!)

PS, just to say Emporia shows the Ecodan is drawing an average of about 1.1kWh each hour, so our COP adjusted 8.5kW ASHP is more like a 3kW heat pump at the moment, which is clearly not enough to keep even our well-insulated bungalow (c180m2) warm.

Hi all, We've just got back from a weekend away to find our ASHP-underfloor-heated house rather cold (17C versus thermostat settings of 20-23C in various rooms). Obviously it's cold outside (-0.9C at present) but we've never had this before and our system has been in 12 years. It's a Mitsubishi Ecodan 8.5kW pump. Both the ASHP and the underfloor heating appear to be on. The UFH is showing demand from all zones as you would expect. The ASHP is in Heating Eco mode and has the target water temp set to 43C. Checking the power use of the ASHP with my Emporia monitoring I see that it is cycling between no power and full power (c.2.6kW) every 10 minutes or so, as follows: Here's a cycle in second intervals: Over the same 10 minute cycle the actual water temperature rises from 27C to 46C and then falls rapidly back again to 26-27C once the ASPH stops. It feels like the problem may lie with the UFH circulation rather than the ASHP. As I say, we had the system for 12 years without issue and we've been able to keep the house nice and warm through previous snaps. If anyone has got any ideas about what the issue is, I'd be grateful. Thanks

Just thought I'd mention that Earthwise got back to my question about whether there was any way they could recommend to combine a Solic 200 and a timer, with the following fulsome reply: "Hi, The SOLiC is designed to mounted on its own dedicated circuit so fitting a timer is difficult. Thanks Iain CM McRitchie, FCCA Director" So that'll be a 'no' then.

Er... Sorry to butt in on this one but in our FIT scheme at least we get an export payment for 50% of what we generate, regardless of how much we actually export. That is because the company paying our FIT (Energy Warehouse) has no way of knowing how much we actually export - there is no meter for that. So an assumption is made that we export 50%. We don't have a battery - I've looked but I still think the pay-back is too long, we don't plan to be in this house for many years. But if we did install a battery, we'd still get an export payment for 50% of what we generate even if never exported anything. Edit: Apols @FerdinandI see you have made the point about 50% assumed export where you don't have an export meter.

Thanks for the suggestions everyone. I have contacted Earthwise to see what they suggest. Don't know why I didn't think of that before. As has been suggested the Boost function would be fine if you could have it happen at say 19:00 every day. (Maybe I should build a little bot to press the button each evening 😁) The changeover relay/contactor solution sounds like it ought to work but I would need to get my head around it to be totally confident. It will be interesting to see if Earthwise recommend that. Thanks once again for all the ideas!

Many thanks for the reply. Yes, it would be nice to fix the ASHP issue but... it's an early Ecodan 85 with an FTC2 controller, bought and installed very cheaply 12years ago, without a warranty. Several (Mitsubishi companies) people have been to look at it but none could solve the problem. The latest, this year, said our best option is to live with it until the ASHP fails when it will probably be cheaper to put a completely new unit in rather than trying to fix it. Regarding a timer. We have used the LAP timer (not the most reliable tbh, failed after a couple of years). We do have a very good digital timer on the immersion heater now but the question is: how can we run a timer and the PV diverter in parallel, so that the PV diverter heats the HW during the day when we have excess PV and the timer comes in in the evening if there has not been been enough PV to take the HW up to the IH cut-off temperature?

The Earthwise Solic 200 looks like a good piece of kit for half the price of its competitors but doesn't seem to include a timer to force the immersion heater on if the tank has not been heated up during the day by diverted PV. Currently, we have to use an immersion heater to heat our hot water in the winter because our old ASHP controller has always locked out when trying to heat HW. (Although we do have solar HW too which works well in the summer.) So ideally, I'd like the immersion heater to use diverted excess PV during the day and then come on for a couple of hours during the early evening (from the grid) to heat the HW if it is not up to temperature. Anyone know a way I could combine a time and the Solic 200? Thanks!

Lol yes, maybe that's right. As least we will be able to drink the contents of our wine cellar as we go. 😉

Sorry to post this but I'm having some dark thoughts... I have 4kW of PV panels, no battery. I appreciate I cannot use the power generated by the PV during a grid power cut. But if the worst happened with Russia and the grid failed permanently, yet here in rural Dorset we were still alive, is there anyway I could completely disconnect from the (non-working) grid and configure the panels and inverter to make use of that PV generation during the day?

Haha thanks - I think I'll save that for the day Emporia want to start charging a subscription!

I cannot post any photos at the moment due to time constraints but will aim to post some later this week. Yes, the app does show what you are exporting to the grid. The app is available on iPhone, iPad or browser. It has the same look and feel on both iOS and the browser. I assume there is an Android version too. (Edit, yes there is) The app shows Net usage, PV generation, and Total usage, then spilts the total usage by circuit, depending on how many sensors you have. So if PV generation is zero (e.g. at night) Net and Total are equal. If PV generation exceeds Total usage, Net usage is shown as negative (i.e. you're exporting to the grid). You can view by second (so effectively your realtime usage at that moment), by minute, hour, day, week, month or year. For day/week/month/year you also get total amounts 'In from grid and "Out from grid' shown. You can select which day week or month you want to look at (I'm not sure how far back you can go - hang-on, looks like a month for day data, six months for week data, two years for month and year data). The data is stored on Emporia's storage (this is a disadvantage - fears they could charge fro this in the future). You can download a .csv table of your recent data to feed into your own spreadsheets or database. Early days so far but the app is much batter than I expected it to be.

That's beyond me, I'm afraid. I can't really understand why the direction of the sensors is important but it seems to be.

Ah, and... Our Ecodan 8.5kw ASHP is using 27 watts on standby, which I am ok with tbh.

Quick update: I took the plunge with an Emporia Vue £160 on Amazon with 16 x 50A sensors. So far, so good. Here's some thoughts from the Amazon review I posted earlier today: A clever product which seems to work well. Good app and great support. This was a UK DIY install. A few notes re installing in the UK: I managed to fit 15 50A sensors in my consumer unit. It was a bit of a squeeze but it all fitted in ok (see photos) Make sure you get each sensor round the right way, they are clearly labelled 'breaker' with an arrow (in the photo, I have two sensors, 3 and 7, upside down, I fixed that before closing the consumer unit). The 16th 50A sensor went on the PV feed live, the 200A on the live from the grid supply meter. The device itself was definitely not going to fit in the consumer unit. I therefore shortened the 4-wire power lead and connected it to a two-core connector: red, white and blue leads to neutral, black to live, with some shrink wrap over the wires for neatness and to provide double insulation. You can see this in one of the photos. The other end of the connector is wired into a standard UK 3-pin plug which is plugged into a wall socket. This works fine, no need as far as I can see to wire the power lead directly into the consumer unit. I guess the only issue is that you could accidentally unplug the power lead or switch the wall socket off, at which point you'd lose monitoring of course. As our socket is in the service cupboard this isn't really an issue. I did have an issue after the install when trying to configure the device via the app. It failed at the point I told it I had solar PV. Within the app there is the option to connect to a chat support service, which I did. The guy (James) was really helpful, checked lots of things with me. He was a bit worried that the unit wasn't powered directly from the consumer unit but... eventually we discovered I had made the novice mistake of putting the 200A sensor on the live feed from the meter THE WRONG WAY ROUND (doh!) Once I flipped it, it all worked fine. Tbf I have one further minor problem - the tip of the jack plug has broken off one of the 50A sensor leads. I don't think that was me. I actually have 15 circuits plus the PV so ideally I could use all 16 50 A sensors. I have emailed Emporia to see whether they can replace it or whether I should go via Amazon. I suspect it will be fixed without issue. Anyway overall a good product and very good support. Aimed primarily at the US & Canada but it's working well for us. I can now see how much of our PV generation we are actually using minute by minute, and how much we are giving to the grid. This will help us decide whether batteries would pay for themselves.

Thanks! I'll take a look

I can only find a US site and they don't seem to have all the components in stock 😞 I can't find iotawatt on Amazon.

Thanks joth and billt, lots of info there. It seems like most of my concerns can be overcome. I'll also take a look at iotawatt. Cheers

Er... isn't that what PhilT did, and posted their answer on 6 June?

Thanks I will take a look at that. Yes, I read the thread about the Ecodan base load concern - I am not sure if there was a conclusive answer though? It's one of the reasons why I want to start monitoring.

Thanks for the reply SteamyTea. Have I got a meter already? Only the BG smart meter which does not work most of the time 'because of cellular phone issues'. I could probably manage to link an Arduino to a cheap meter to do some logging (I have done some Arduino projects before although I am a bit rusty now) but I am not sure I want to devote the time to that if I can buy something off the shelf for £100 or so. Some of the questions I want to answer are not to my mind obvious. For example, our ASHP has always been 'on' 24/7/52, with usage controlled entirely by the room stats (so it's not really operating this time of year). This works well from a comfort pov, but is there a background load? How much does our pond pump and filter cost us to run? Should I keep the MVHR running through the summer? Could we run certain things at a time better optimised to use the PV power we generate? etc.etc.

Hi all, I am thinking of buying an Emporia Gen 2 Vue Energy Monitor with 8 or possibly 16 50A sensors to help further improve our energy efficiency. We have an all-electric, well-insulated house but the running costs are now going up with recent energy price rises. The house has underfloor heating run from a Mitsubishi Ecodan 85 ASHP. We also have 4kW of PV panels, solar hot water and MVHR. I'd like to be able to monitor the electricity use in detail hence the potential Emporia purchase. I know these devices hold the data on a cloud, with potential future risks that that poses but still they seem the best option at the moment. I have some questions which I cannot get clear answers to from the Emporia website. If someone has one of these units or knows the answers to my questions, I'd appreciate any thoughts... The device has two 200A clamps which need to go around the L and N supply leads into the distribution box. Why both leads? Just curious. Does this device measure the live voltage or make a voltage assumption to calculate the power level? Can I measure the PV panel output on this device too? If so how? If we are feeding into the grid will the monitor distinguish that, or see the power going through the supply leads as an absolute value (i.e. will a 1kW feed into the grid from our PV panels look like we are using 1kW from the grid?) The instructions say the clamps have to be fitted inside the consumer unit (CU). Anyone know why? The issue for me with fitting them inside the CU is that the ASHP, UFH, MVHR and solar water are all on one CU circuit, so I wouldn't get any granularity about the individual demand from each of those devices... ...Also, is it safe to open the consumer unit to fit those clamps, if the main switch is off? (Obviously I can be careful not to touch any bare wires but it sounds a bit scary to me!) If I clamp a 3-core cable (e.g. the individual supply to the ASHP) would I get a double reading, or zero? (i.e. would the currents running through the live and neutral wires be added together or cancel each other out?) Sorry, that's a lot of questions but if anyone can answer some of them, I'd be grateful. Many thanks Benpointer

Hi all, Just to briefly introduce myself: We completely refurbed a 1960s bungalow 10 years ago, building a SIP two storey extension, more than doubling its size, adding cavity and external wall insulation to the original bungalow at the same time. We installed underfloor heating driven by a Mitsubishi Ecodan 85 ASHP. We also added 4kW of PV panels, solar hot water, MVHR, and rainwater harvesting. We did all that back in 2009-10 and at the time I got a lot of help from the old Navitron forum. Since when we have been enjoying the house and been very pleased with the results. I have joined Buildhub now because: Whilst originally the PV FITs were covering our electricity costs, that's a long way from true now. So I am looking at what further efficiencies we might make. I think we will do another house project in a few years, maybe a new build but we'll want it to be as efficient as possible, so I could be seeking thoughts, ideas etc. As an aside I am secretary for our small village hall, which is a converted stone 19th chapel. The heating costs have gone through the roof (as does most of the heating tbh!) so I might be looking for any ideas members have about managing heating costs for a building that is unoccupied most of the time. I apologise that it looks from that list as though I am just on the take but hopefully, with our experience of a major eco-rebuild I can offer some ideas in return. Anyway, that's me introduced! Benpointer