Post and beam Posted January 20, 2023 Share Posted January 20, 2023 Hi guys Research is ongoing. I have been directed towards one of these heat pumps. I have not heard of them before. Grant aerona 3 Link to comment Share on other sites More sharing options...
HughF Posted January 20, 2023 Share Posted January 20, 2023 Made in Japan by Chofu. A good unit when installed correctly. The grant installation instruction’s essentially install it as an oil boiler which clobbers the efficiency. Link to comment Share on other sites More sharing options...
JamesPa Posted January 20, 2023 Share Posted January 20, 2023 32 minutes ago, HughF said: A good unit when installed correctly. The grant installation instruction’s essentially install it as an oil boiler which clobbers the efficiency. Well doesn't that comment, to the best of my knowledge accurate, say something deep about how the profit motive (or laziness or ignorance) can lead us to dumb down things to the point where the point is negated. I doubt many install an ASHP because its the cheapest or most convenient option, the point is that its eco friendly (whilst possibly being no less convenient and no more expensive). Clobbering the efficiency thus clobbers the point. If your analysis is correct this is clearly immoral, and should be illegal under trading standards rules. Profoundly sad! Of course the knowledgeable will simply ignore the instructions and do the right thing. it would be interesting to know whether that's a majority. Link to comment Share on other sites More sharing options...
Post and beam Posted January 20, 2023 Author Share Posted January 20, 2023 36 minutes ago, HughF said: Made in Japan by Chofu. A good unit when installed correctly. The grant installation instruction’s essentially install it as an oil boiler which clobbers the efficiency. I have no idea what that means Link to comment Share on other sites More sharing options...
HughF Posted January 20, 2023 Share Posted January 20, 2023 1 hour ago, Post and beam said: I have no idea what that means In which case you probably shouldn’t be worrying yourself with what heat pump you should buy and instead focus on a competent installer who you can trust. I’d suggest Brendon Uys from Heacol. Link to comment Share on other sites More sharing options...
JohnMo Posted January 20, 2023 Share Posted January 20, 2023 Grant install a modified Y plan, to make it easy for installers. If you went with the Grant badged unit, you need to educate yourself on how they should be installed, or go elsewhere. Link to comment Share on other sites More sharing options...
Post and beam Posted January 20, 2023 Author Share Posted January 20, 2023 1 hour ago, HughF said: In which case you probably shouldn’t be worrying yourself with what heat pump you should buy and instead focus on a competent installer who you can trust. I’d suggest Brendon Uys from Heacol. I disagree of course. Link to comment Share on other sites More sharing options...
Post and beam Posted January 20, 2023 Author Share Posted January 20, 2023 4 minutes ago, JohnMo said: Grant install a modified Y plan, to make it easy for installers. If you went with the Grant badged unit, you need to educate yourself on how they should be installed, or go elsewhere. My interest is trying to discover if this brand is reliable and viable for domestic use and also value for money. I have no interest in how to install one, thats what a competent installer is for and thats not me. I would engage somebody that i believe is trustworthy Link to comment Share on other sites More sharing options...
Bonner Posted January 20, 2023 Share Posted January 20, 2023 I have just had one installed so too early to recommend. Came with a 7 year warranty for what it’s worth. 1 hour ago, JohnMo said: Grant install a modified Y plan, to make it easy for installers. If you went with the Grant badged unit, you need to educate yourself on how they should be installed, or go elsewhere. @JohnMo, might be too late but how do I find out how it should be installed? Link to comment Share on other sites More sharing options...
ReedRichards Posted January 20, 2023 Share Posted January 20, 2023 (edited) 4 hours ago, Post and beam said: I have no idea what that means I would say there are three ways you can configure a heat pump: Like an oil boiler with a fixed output water temperature and just an on/off control to maintain your room temperature (probably with a limit to the number of starts per hour to prevent short-cycling). This configuration results in the highest running cost. Like a (more sophisticated) gas boiler where Weather Compensation is used to reduce the flow temperature as the outside temperature gets warmer. You might also get Load Compensation but few heat pumps offer that feature and you have to use the manufacturer's own controller/room thermostat. Advanced ("hard core") where you abandon the use of thermostatic controls and tweak your Weather Compensation settings and radiator/UFH flow rates to keep your house at a constant temperature as the outside temperature varies. This could take a lot of tweaking to perfect and not all heat pump controllers allow you to make a night-time setback if you don't want the same internal temperature 24/7. But this should give you the most economical operation. There's another separate issue with how you ensure your heat pump operates with a minimum volume of water (as they require). Edited January 20, 2023 by ReedRichards Link to comment Share on other sites More sharing options...
JohnMo Posted January 20, 2023 Share Posted January 20, 2023 28 minutes ago, Bonner said: might be too late but how do I find out how it should be installed? Chofu-Operating-Installation-Manual.pdf Key difference is how they use the controller and generally connect it all up. The manual attached is very similar, just lots of pages longer and features cooling also. 1 Link to comment Share on other sites More sharing options...
Nick Thomas Posted January 20, 2023 Share Posted January 20, 2023 I have one of these, the aerona3 6kW using R32. Installed by a not-so-competent installer, emitters are radiators and there's a buffer tank. They offered to turn weather compensation off but I politely declined that ^^. Not sure what to tell you, it does the thing and isn't overly expensive to run. I'd prefer something with easy modbus integration for local control, but it's not a huge quibble. Link to comment Share on other sites More sharing options...
JohnMo Posted January 20, 2023 Share Posted January 20, 2023 13 minutes ago, Nick Thomas said: I'd prefer something with easy modbus integration for local contro I think that's one of the key differences, you have a control which grant hide away so you can't mess with it. The original manufacturer uses it as a full function controller Link to comment Share on other sites More sharing options...
Bonner Posted January 20, 2023 Share Posted January 20, 2023 19 minutes ago, JohnMo said: Chofu-Operating-Installation-Manual.pdf 3.15 MB · 10 downloads Key difference is how they use the controller and generally connect it all up. The manual attached is very similar, just lots of pages longer and features cooling also. Thanks, I will have to digest this and see how I can get the best efficiency from the HP Link to comment Share on other sites More sharing options...
Nick Thomas Posted January 20, 2023 Share Posted January 20, 2023 (edited) 7 minutes ago, JohnMo said: you have a control which grant hide away so you can't mess with it. The original manufacturer uses it as a full function controller They left the controller fixed to the UVC in the airing cupboard, so it thought it was always 30°C indoors. Made a difference to the weather compensation! I moved it so it's on the upstairs landing now, and I guess it's fine, but it's not what I had in mind, which is https://github.com/aerona-chofu-ashp/modbus . Possible, but a bit too skunkworks for me - i'd rather Grant/Chofu sold a little dongle that I could talk to rather than having to fiddle, and some heat pump manufacturers do. Edited January 20, 2023 by Nick Thomas Link to comment Share on other sites More sharing options...
HughF Posted January 20, 2023 Share Posted January 20, 2023 2 hours ago, Post and beam said: I disagree of course. I wasn’t talking in tongues, I figured as you were smart enough to operate this forum, you were smart enough to figure out what I was saying. Link to comment Share on other sites More sharing options...
HughF Posted January 21, 2023 Share Posted January 21, 2023 13 hours ago, Nick Thomas said: I have one of these, the aerona3 6kW using R32. Installed by a not-so-competent installer, emitters are radiators and there's a buffer tank. They offered to turn weather compensation off but I politely declined that ^^. Not sure what to tell you, it does the thing and isn't overly expensive to run. I'd prefer something with easy modbus integration for local control, but it's not a huge quibble. The Chofu modbus integration is pretty well documented, iirc… Link to comment Share on other sites More sharing options...
HughF Posted January 21, 2023 Share Posted January 21, 2023 12 hours ago, Nick Thomas said: They left the controller fixed to the UVC in the airing cupboard, so it thought it was always 30°C indoors. Made a difference to the weather compensation! Standard heat pump install then….. Leave the manufacturers supplied controller somewhere inaccessible and give people a Hive (shudder) ‘Smart’ thermostat 🤦♂️ At least it wasn’t in the loft… Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2023 Share Posted January 21, 2023 I installed a Grant ASHP this time last year on a new build being built for sale. I didn't do the plumbing and was not impressed with the plumber that did, he did not use blending valves or even pumps on the UFH manifolds, he just relied on the water pump inside the ASHP to push the water everywhere. But it did seem to work. I wired it according the the installation manual. It was very basic, a call for heat input and a call for hot water input, and the only controller used was the one Grant supplied. It all appeared to work but I never delved deeply into the finer details. but one thing that struck me was if you did a bit deeper than the basic "how to connect it" instructions, is there are a lot of additional inputs and outputs and a lot more things it can do, but most not very well explained. Link to comment Share on other sites More sharing options...
JamesPa Posted January 21, 2023 Share Posted January 21, 2023 (edited) 16 hours ago, ReedRichards said: I would say there are three ways you can configure a heat pump: Like an oil boiler with a fixed output water temperature and just an on/off control to maintain your room temperature (probably with a limit to the number of starts per hour to prevent short-cycling). This configuration results in the highest running cost. Like a (more sophisticated) gas boiler where Weather Compensation is used to reduce the flow temperature as the outside temperature gets warmer. You might also get Load Compensation but few heat pumps offer that feature and you have to use the manufacturer's own controller/room thermostat. Advanced ("hard core") where you abandon the use of thermostatic controls and tweak your Weather Compensation settings and radiator/UFH flow rates to keep your house at a constant temperature as the outside temperature varies. This could take a lot of tweaking to perfect and not all heat pump controllers allow you to make a night-time setback if you don't want the same internal temperature 24/7. But this should give you the most economical operation. There's another separate issue with how you ensure your heat pump operates with a minimum volume of water (as they require). This excellent summary made me think about the motivations of both installers and customers, and what is needed to change behaviours so that are least most pumps are installed at worst in mode 2. The underlying problem is that mode 1 is quick, thus cheap, and more or less guarantees a warm house. Modes 2 and 3 take progressively more time to set up, more probably than most will pay for, and don't guarantee a warm house unless done well and then tweaked. But an installer needs to set up quickly and leave, not come back when the ambient temperature has changed so (s)he can adjust the slope correctly or wait around while things stabilise etc, and most homeowners don't want to fiddle with the plumbing. So perhaps the question is (given that the motivations are unlikely to change) what technology, information or practical rules of thumb are needed (and can it be made cheaply) to make modes 2 and 3 no more difficult and expensive to set up than mode 1, and just as reliable. Discuss! Edited January 21, 2023 by JamesPa Link to comment Share on other sites More sharing options...
HughF Posted January 21, 2023 Share Posted January 21, 2023 @JamesPa you’ve got the Lizzie curve for WC which is a reasonable ‘set and forget’ WC curve, then you’ve got homely which is an automatic WC/flow temp optimiser, you tell it your target room temp, it figures it all out. Link to comment Share on other sites More sharing options...
JohnMo Posted January 21, 2023 Share Posted January 21, 2023 8 minutes ago, JamesPa said: to make modes 2 and 3 no more difficult and expensive to set up than mode 1 It's not an easy one as two identical houses, will have differing heating needs depending on what the owners feel is right. You may be happy with 19 degrees, the next person not happy unless it's 22. This gives a different curve and different heating profile. Mixing in load compensation with WC is fine in concept, but with low temp UFH leads to over and undershooting, the system response is out with the controller parameters. Link to comment Share on other sites More sharing options...
JohnMo Posted January 21, 2023 Share Posted January 21, 2023 1 minute ago, HughF said: Lizzie curve So what's that? Link to comment Share on other sites More sharing options...
HughF Posted January 21, 2023 Share Posted January 21, 2023 1 minute ago, JohnMo said: So what's that? 45@-2/-5/-whatever, 37@15 Graham Hendra (freedom heatpumps) came up with it as a good starting point that stops people phoning up and complaining that their radiators don’t feel warm. Link to comment Share on other sites More sharing options...
JamesPa Posted January 21, 2023 Share Posted January 21, 2023 (edited) 4 hours ago, JohnMo said: It's not an easy one as two identical houses, will have differing heating needs depending on what the owners feel is right. You may be happy with 19 degrees, the next person not happy unless it's 22. This gives a different curve and different heating profile. Mixing in load compensation with WC is fine in concept, but with low temp UFH leads to over and undershooting, the system response is out with the controller parameters. There is a severe danger that the perfect gets in the way of the good, to the advantage of the bad. If doing it perfectly is too complex most will default to mode 1. I wonder if anyone has done some calculations to work out where an easy compromise lies (and what penalty is paid for the compromise) something that's easy and good, if not perfect. Something like the Lizzie curve plus balancing the emitters for consistent delta T (which is easier than balancing for room temperature) maybe. I wonder what the Germans do, they have had weather compensation on their boilers for decades. Edited January 21, 2023 by JamesPa Link to comment Share on other sites More sharing options...
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