Hogboon

It very possibly was windy - fag end of Arwen or early onset Barra? - but I don't take note of any met. conditions other than outdoor temp. I agree with ReedRichards and find that LG's 'cutting edge technology' needs help from a recently acquired thermometer costing £1.50 from the garden centre. [Same with the so-called electricity 'smart meter' which is incapable of recording input to the grid from my pv roof panels.] In view of the MASSIVE sums of money to be earned from heatpumps - especially retro fitting them - the technology and support for end users such as myself, who am neither plumber nor engineer - is utterly inadequate and beyond belief. I have no experience of any make of heatpump other than LG so whether they are particularly bad I don't know, but as things stand at present if someone told me they were thinking of installing an LG I would say DON'T! [at the top of my voice!] Meanwhile, as a spot check today, with outdoor temp around 4º C and AI at +5 running 'continuously' the 07:00 starting temp of the house was 18º and by 08:00 was 18.7º and at 09:00 it was 19.1º so it looks like it should get to 20º by about 11:00. Fingers crossed...

Thanks ReedRichards and ProDave. I will persevere with the current A1 at +5 for 4/5 days but after day 1 it's not looking promising! Next up will be a similar 4/5 day continuous 24 hour run with AI 'off' and use the alternative 'Heat' mode. Such fun!

J1mbo: “The house is being allowed to cool too much. Set the hive, if you must use that, to 18 degrees between 10 and 7… “This is where things get interesting. If the heat supply was a gas boiler then of course it will be cheaper to heat it for 15 hours. It will use less energy and cost less.” Done. I have just finished two x 4-day regimes for comparative purposes to test J1mbo’s assertion that “…the amount of electricity required is actually more when operating the shorter heating period than just leaving it on 24 hours” Spot on! Here are my figures. The ‘benchmark’ data [26-29 Nov] are for my previous schedule i.e. turning the heating and hot water OFF between 22:00 and 07:00 Date Time ON AI kWh consumed £ average 26 Nov 15 hrs +1 25.4 = 5.01 27 Nov 15 hrs +1 29.6 = 5.84 28 Nov 15 hrs +1 32.4 = 6.40 29 Nov 15 hrs +1 22.0 = 4.34 £5.40 The comparison figures are for leaving the heatpump ON for 24 hrs save that the target temperature between 22:00 and 07:00 is 18º rather than 20º. Thus the system must heat the house from 18º to 20º between 07:00 and 22:00 Date Time ON AI kWh consumed £ average 4 Dec 24 hrs +1 24.08 = 4.75 5 Dec 24 hrs +1 23.08 = 4.56 6 Dec 24 hrs +1 28.42 = 5.61 7 Dec 24 hrs +1 25.35 = 5.00 £4.98 Which basically means I am a 24 hour ‘continuous’ convert. The improvement in kWh consumption and thus cost is in line with J1mbo’s prediction of 7% - in my case slightly under 8½% by my calculation. But I include the £ as they mean more to me than kWh. Domestic consumption across the two series was comparable as was the weather – hovering a few degrees above zero. I'm wirh ReedRichards when comes to oddity. "If you have a Hive room thermostat then selecting Air or Air + Water would surely cause the Hive to "fight" the LG controller as they are both trying to set/control an air (i.e. room) temperature. So, I think, the only sensible option is to select Water (being the leaving water temperature) as the parameter used for control. If so then the Indoor temp for auto mode is irrelevant (or N/A as it says in my installation instructions). You can set whatever values you like but it should not make any difference." It is set to ‘WATER’ alone. The coolant I believe is R32. What continues to perplex me about my system is the seeming unpredictability of the heatpump’s performance - let alone my ability to control it. For example yesterday the heatpump failed completely to raise the house temp to the required 20º for no apparent reason. The house got there in the end but only after the log-burner was lit. I am now running a similar 4 day schedule essentially the same as the previous 24 hrs regime [4-7 Dec] but with AI set to +5 and will post the results here when completed.

This was on my list of 'Things to Ask.' Presumably no-one sets out to manufacture a noisy machine so if there is a 'quiet' mode the trade-off is presumably a loss of efficiency - the machine running slower therefore taking longer to reach target temp and concomitantly using more electricity. Or am I wrong? If right, is the trade-off penalty so slight as to be negligible? B.t.w. I am poised to go 24/7 to assess grid consumption on my installation. And thanks for your other answers J1mbo. I only absorb such detail slowly but hopefully, like the tortoise, I will get there in the end.

How interesting ! Using less grid power 24/7 compared with 15 hrs on/off is impressive. My aversion to having the heat pump on 24/7 is not entirely on, as it turns out, fallacious grounds of economy, but also partly due to the noise waking me up but does your calculation take into account the fact air temperatures at night tend to be lower than those in day time? so to extract xº heat the heat pump will have to run for longer and/or work harder? The other admittedly small factor favouring my 15 hour on/off regime is that no benefit can be derived from the PV roof panels during approximately half the working hours of the heat pump in continuous operation since when most required, i.e. midwinter, it is dark for approx 12 hours in 24. The other detail that strikes me is that even given my wayward requirements, the perverse behaviour of the system is not explained. There are occasions early in the day on 27 and 28 Nov [and again today] when the heat pump squirts out sufficient heat to raise the house temp by 0.4º If it did that consistently starting from say 16º C at 07:00 it would reach the target temp in about 5 hours rather than the 9 hours it is averaging at present. For the record, replacing the radiators is a no-no.

Thanks ProDave. Presumably for the purposes of house heat I do not need to fiddle with any settings for 'hot water mode' ?

Got it - thanks! So when the manual says to set the heating temp higher than the water temp., is it the 'LWT' they mean? My current settings are in 'heat' mode for 'Operation' the temp = 50º but the "water heating temp" in Installer settings = 20º-50º Do I need to change anything? [Similarly when operating under 'Auto' the LWT for auto mode is currently set 30º - 50º. Anything to change there?] ... and everything else!

Good morning J1mbo! Nice to have you on board again. I have just 'popped in' to upload the graphs here in the order they should have appeared as I seem unable to add them to the original post. I'm currently trying to stay awake r.t.f.m. On p. 20 it says: "Leaving water temperature...Set the desired temp higher than the water temp." What desired temp? The heating temp? The house temp? The water temp? and, come to that what 'water temp' - the leaving water temp? [and is that the same as LWT? re the installer settings?] Attached are all my current 'Installer settings'. installer settings.pdf

The answer to my opening question "would a bigger pump etc" seems to be "probably not". This post seems to have been based on the false premise that the unsatisfactory performance of my heatpump is due to poor flow - either from small pipes or inadequate pump. So with thanks to all those who stuck their necks out and proffered advice, knowledge, know-how etc and I now draw a line under this post - only to set another hare running under the title "Optimising LG Therma V Controller Settings". You never know; there might be someone 'out there' with a similar installation to mine and a similarly antiquated attitude to thermostat schedules etc who has already invented the wheel, in which case I'd be delighted to hear from you! Ttfn.

OBJECTIVE: to reach and maintain the target house temperature of 20º C as efficiently as possible. Which begs the question ‘define efficient.’ As far as I am concerned, this is the shortest time taken to attain the target temp and the lowest energy consumption thereafter in maintaining it. CONTROLS. As far as I can tell I have no way of controlling power [i.e. electricity] consumption other than through the LG controller. MEASUREMENTS. There is a separate electricity meter for the heatpump. Half-hourly readings are recorded during the schedule as are the outdoor and indoor temperatures. SCHEDULE. The heatpump is turned OFF between 22:00 and 07:00. From 07:00 to 22:00 the target house temperature of 20º C is controlled by a Hive thermostat. The DHW [hot water] is controlled by – you guessed it – the Controller. I occasionally turn it OFF in order not to interfere with collection of house heating data. I am fully aware that this schedule [especially being off between 22:00 and 07:00] is open to criticism but I am the customer here; there are reasons for adhering to this schedule which are IRRELEVANT for the purposes of this topic. I am/we are where I am/we are and I start from here. The INSTALLATION. LG Therma V 14kw monoblok ASHP. Worldheat High Gain unvented tank with system buffer, low loss header and immersion heater. A roof array of 12 x 320 w PV panels a] to supply power to the heatpump b] to heating hot water and c] surplus energy to grid. The HOUSE. 1½ storey 5 bed detached bungalow built c. 1975 described in EPS as 176 m². Double glazed throughout with insulated walls and roof [although could probably do with more in roof] Solid floors to ground floor assumed uninsulated. Existing radiators upgraded at installation of heatpump to 15 in total with new pipework replacing 10mm micro-bore; 22mm flow and return with 15mm drops to radiators. No under-floor heating. No other source of heating other than one small log-burner lit regularly in the evening. Space heating demand: 16,184 kWh per year. Water heating demand: 3,537 kWh per year. Total heat loss seems to have been 21,729 The story so far – or as they say on telly “Previously…” I altered some of LG’s Controller Installer settings as follows: Outdoor temp for auto mode: min -10º max 15º changed to -1º/15º Indoor temp for auto mode: min 16º max 21º changed to 18º/23º LWT for auto mode: min 20º max 50º changed to 30º/50º All other settings were left at their original or ‘default’ settings. Whether these were from the manufacturer or installer I have no idea. [Someone new to this thread might wonder why I do not get the installer to see to any/all of this. Tried that and failed. Also their level of understanding seems even more basic than mine; at least I know what the password for the Installer menu is!] Apart from the general thrust of this post I have a couple of other specific questions relating to the above. 1. Using ‘Auto’ in the ‘User’ menu on the LG Controller what exactly do +1, +2 etc pr -1, 2 etc do? Is this some sort of temperature override or instruction to increase/decrease the thermostat temperature setting? 2. In the LG Controller Installer settings, what should I set for ‘Temperature Sensor’ ? The options are air or water or air+water. It is currently set to water. Here is a graph of the heatpump’s performance from yesterday. Missing data points are those where I forgot or was unable to make a record. The user settings were ‘Auto’ and set a +1 [graph not uploaded for some reason. will fix tomorrow] It started off quite briskly but then ‘relaxed’ as if the aim was to arrive at the target temperature mid-afternoon rather than get there a.s.a.p and maintain it there till shut-down at 22:00. What I want is the graph to resemble the FICTITIOUS representation below. [graph not uploaded for some reason. will fix tomorrow] Today’s data was collected with the user’s ‘Auto’ set to ‘Heat’. Here’s the graph. [graph not uploaded for some reason. will fix tomorrow] There is a slight ‘improvement in performance on 28 Nov but apart from that there seems to me little difference between the two. Apart from starting from a slightly lower temperature on the 28 Nov, and reaching the target temperature a little quicker than under the ‘Auto’ setting the curves are pretty similar and display a tendency to delay getting to the target temperature until mid afternoon which is not what I want. Finally 3 sets of data for comparison of kWh consumption for 26-28 Nov. a] to reach 20º C from the starting temps. at 07:00 and b] total power used from 07:00 to 22:00 hrs. Starting tempº C kWh to 20º KWh 7am-10pm User setting 26 Nov 17.4º 20.4 25.4 Auto 27 Nov 17º 24.81 29.56 Auto 28 Nov 16.7º 24.91 32.37 Heat Apologies for droning on at such length! and many thanks for any practical advice.

As mentioned previously, the menu options on my controller do not include one for 'Energy.' It sounds exactly the sort of thing that is needed so why it is not included on my controller when it is clearly described in the User's Manual is beyond me - like almost everything to do with heatpumps! The only Menu options on my Controller are for Setting, Schedule, Lock and Timer. The Controller's 'Home' page [if that is what it is called] currently looks like the image below. Should anything there be tweaked? 'Intuitive' is clearly not in the South Korean lexicon.

Cor blimey ! if that is allowed these p.c. days. It wasn't on 'auto' but now [09:00] is, and icons etc have gone a rather fetching purple which would impress my grand-daughter as it is currently her favourite colour. All other settings remain as before. Thanks for that J1mbo.

Quite right Luke1 ! Had a look and there it is - an Emlite M20. What I had been expecting was something resembling the attached. I assumed that setup was what was required for RHI instead of which there is one small meter 10 feet off the ground in a dusty corner of the garage only frequented by tarantulas. Meanwhile the heatpump seems to have reverted to its old ways. Yesterday started 'chilly' [but above freezing] and thereafter was 8-10º yet the heatpump took from 07:00 till 16:00 to raise the house temp from 17.7º to 20º. As my wife was awol for the whole day there were no additional demands via hot water and the doors and windows were not all open. I will get back in touch with LG, explain the setup and heat requirements here and see if they have anyone who understands how to configure their equipment. Frankly, I consider yesterday's performance totally inadequate. [LGMMSP C_10_19v1] LG MMSP Wiring Diagram Plus Cloud Set Up (2020) (1).pdf

Installer's response: I have asked for its location. What the "additional LG equipment" might be I have no idea unless it is LG's PENKTH000 mentioned in an earlier post but my understanding from LG was this form of metering was unacceptable for RHI. If it's unacceptable to them why would I want it? I'm not doing any of this for fun! I don't want to "measure SCOP" etc but do want to know if the heatpump is performing efficiently etc. Currently there seems no way of telling, but if the metering required for RHI is installed then presumably that could tell me what I want to know. Right now the heatpump is still churning away trying to raise the house temp from 17.6º at 07:00 to 20º. Current temp [at 12:45] still only 19.1º Outdoor temp here [near Taunton] about 8º.

More 'strewth - but this time spelled with a eff. My 'contact' with RHI, if such it turns out to be, was via a friend who tells me that, according to them, they aim to respond within 10 working days, so I shan't hold my breath. Have meanwhile fired a broadside at the installer and await a response.