suspicious_squirrel

Just a quick update: I dug out the original paperwork, the MCS "customer heat pump proposal pack" has an estimated SCoP of 3.91 at a flow temperature of 45°C (3.65 at 50°C for DHW). There is a caveat that it could be 30% lower than this, which I beat by 0.163 today! Though I'm also running far lower water temperatures...

Intelligent octopus Go, 23:30 - 5:30. Ah, my sensocomfort is wall mounted next to a 3d printer so sometimes it's the perfect spot, other times not so much. (it's on command strips so I can move it) When I navigate to the "circulation pump: on" I'm unable to change its state (no option to open it) Ah yes, run time 533h with 835 on/off cycles, so about 40 min cycles. I'll put a pin in macrame, but that garden is looking scruffy.

Just an additional thought, is there a way to monitor the ahsp run time? It seems to prefer to run hotter rather than longer. It’s hard to confirm this though since despite the assurances from the tabloids, I can’t hear when it’s running despite being sat about 2m away (inside)

Cheers, do you know what your heat curve is set to? I gave the overnight running a lot of thought, if we used the setback we'd maybe save off peak rate use in the evening, but then in the morning have the house ramping back up just after the cheap rate ends. I don't think there'd be much in it, but the current system feels like the most cost effective and comfortable. The adaptive and Room Mod moves me off pure weather compensation and relies on the indoor units thermostat doesn't it? I thought pure weather comp is normally best if you can get the curve dialed in. I'll have a look at the DHW stuff next, with the overnight tarrif even at a CoP of 1 it'd beat gas. I'll switch that off, could you tell me what "MO 2" is? No secondary pump, which I assume dosen't help my CoP since I assume the 50w (?) is being accounted for when with an external unit it'd be hidden. So a few of just having changed "Adaptive heat curve" to activated and I've had the follow results: 11th Nov Heating: CoP of 3 at 10.2°C outside temperature (total energy consumption 8.4 KWh) DHW: CoP of 3.5 at 12-12.3°C outside temperature (total energy consumption 1.7 KWh) (it was warmer at 3am than during the day) 12th Nov Heating: CoP of 2.8 at 8.7°C outside temperature (total energy consumption 9.5 KWh) DHW: CoP of 2.8 at 6°C outside temperature (total energy consumption 1.7 KWh) 13th Nov Heating: CoP of 3 at 8.9°C outside temperature (total energy consumption 9.7 KWh) DHW: CoP of 2.9 at 9-9.3°C outside temperature (total energy consumption 1.4 KWh) (another warm 3am) It sounds like there isn't anything drastically wrong with my settings. With the DHW CoP so close to the central heating, should I be looking at improving my pipework for the central heating? For the moment I've upped my heat curve to try and get the ASHP to run a bit harder to see if that helps things. - This is only temporary and I'll lower it back down.

Wow, thank you all for the feedback! The DHW tank is 300L and only heated once a day (overnight) to 41°C. The turnover is fairly high because of this, but I'm happy with the once a week legionella cycle just in case everything hasn't been cycled out sufficiently, it does lower the CoP of the DHW by 0.8 on the day it runs though. Yes, I probably have this worse than most since there are no external/supplemental pumps so nothing is hidden from the Vaillant app. I agree with your sentiment, my only concern is that the CoP suffers more as the weather gets colder, I'll be able to gather more data as we get into winter. I absolutely could have, unfortunately the air changes per hour used in the calculations are non negotiable which inflated the heat loss. My more realistic heat loss is 5KW when you reduce the air changes per hour. Done, I'll report back. It often feels like the ASHP is on for a shorter time than it could be (running hotter than necessary), I assumed this was due to its minimum output though. That’s reassuring, thank you. As mentioned I don’t have any external pumps so that is harming my CoP while likely leading to overall power usage. I’m not too worried about gaming it, I was concerned the system was running poorly and this would get worse as the temperature drops. I'll see what effect the heat curve setting has then change these too. The information for the DHW was more to help provide context to the heating CoP. I could probably improve the DHW CoP by running it at midday, but it’d be madness to not use the overnight rate. Yes, the heat loss is certainly lower, unfortunately we had to use the set figures for air changes in our heatloss.

Foreword Hi, a new account here. I feel slightly bad about pitching up and asking for help immediately, but so many of my searches for trying to problem solve for myself end up here. It’s the most knowledgeable place I’ve found so I thought it best. This post has got rather sprawling so I’ve added headings. Introduction I had an ASHP fitted mid September and I’ve not been seeing anything like the CoP I expected after putting everything into heatpunk (4.36 CoP @ 35°C flow) and going off experiences shared on youtube. The set up is a Vaillant Arotherm 7 heat pump feeding the house with a surveyed heat loss of 6.73kW at -2.2°C. The heating is run on an open circuit with our bedroom TRV set to 3 (~20°C) to avoid it overheating at night. The desired temperature is set at 20°C (but set to run in pure weather compensation at 0.5) There is a volumiser on the return and no secondary pump. In my mind this would give the ASHP the best chance of running efficiently even if it used more power to maintain heat overnight rather than ramping up in the morning. Looking at my efficiency and comparing it to others, it feels like it should be 1/100% higher than the ~3 I’m seeing now we’re just getting into the heating season. My first assumption was our heating circuit must be causing the issue, it’s a retrofit for a gas boiler with some pipe runs I can’t trace. Everything I researched (largely from these forums) and then checked appears to be ok though: The flow rate gets to 1207 l/h (20 L/min). The flow and return to heat pump delta is around 3.3°C (measured using a couple of cheap digital thermometers with probes placed 190 cm from the heatpump in/out as the pipe runs). Request I’m now out of ideas, and I thought it best to talk to people who know more than me. Is this normal; am I missing some wider context as to why my efficiency isn’t great; have I messed up the setting; is there something else to check? I’ve listed below some example CoPs from the Vaillant app and also typed out all the (relevant) settings from the thermostat unit. If anything else would be useful I can sort that too. CoP from Vaillant App Low demand: Heating: CoP of 2 at 17°C outside temperature (total energy consumption 0.568 KWh) DHW: CoP of 3.2 at ~15°C during cycle outside temperature (total energy consumption 0.94 KWh) 7th Oct: Heating: CoP of 3.4 at 14°C outside temperature (total energy consumption 3.2 KWh) DHW: CoP of 3.1 at 11.4-12°C during cycle (total energy consumption 1.3 KWh) 12th Oct: Heating: CoP of 2.9 at 10.4°C outside temperature (total energy consumption 6.4 KWh) DHW: CoP of 2.6 at 8.3-8.7°C outside temperature (total energy consumption 1.1 KWh) October Overall: Heating: CoP of 3.2 at 11.3°C outside temperature (total energy consumption 158 KWh, total Heat Generated 507.0KWh) DHW: CoP of 2.9 at 11.3°C outside temperature (total energy consumption 50.8 KWh, total heat generated 147KWh) For comparison a youtube video with the same ASHP from someone local (ish) had heating CoP of 4.6, at a total heat generated of 507.8KWh (shockingly close to my total heat demand) in October. From memory they run a setback temperature of 18°C overnight and have the heat curve set to 0.60 (upsidedownfork) Heat Pump Settings on thermostat unit. Installation configuration Installation Water pressure: 1.2 bar eBUS compontnets [Not imporatant?] Adaptive heat curve: Deactivated Current room air humidity: 51% rel Hybrid manager: Bival. Point Heating bivalence point: -25 °C DHW bivalence pont: -20 °C Heating alternative point: Off DHW alternative point: Off LHM temperature: 25 °C ESCO: Cooling off ESCO contact status: Blocked Back-up boiler: Off Buffer cylinder offset: 10K Max. pre-heatng time: Off OT constant heating: Off Flow temp. Corr. max. Value: 0K Basic system diagram config Basc system diagram code : 8 [DETAILS] HP control module configuration MO 2: Not connected MI: Not connected Heat Pump 1 Status Heating Current flow temperature: 26 °C HP Control Module Status: Off Circuit 1 [Set in the app to 20°C all the time (bedroom TRV set to 3 to stop overheating) in manual Operation] Circuit type: Heating Status: Heating Target flow temperature: 29 °C OT switch-off threshold: 18 °C Heat curve: 0.50/0.55 (0.5 was a little cool) Min. Target flow temperature: 20 °C Max. Target flow temperature: 45 °C Set-back mode: Normal Room temp. Mod.: Inactive Cooling possible: No Pump status: On DHW [Set via the app to charge every night from 3-5:30 to 42°C] Cylinder: Active Target flow temperature: 0 °C Cylinder charging pump: Off Circulation pump: On Anti-lego. day: Friday Anti-legio. Time: 02:00 Cylinder charging hysteresis: 7.0 K Cylinder charging offset: 10 K Max. cyl. Charging time: 90 min Cly. charg. Anti-cycle. Tme: 60 min Parallel cylinder charging: No Noise reduction mode [Empty schedule] Thanks in advance for any suggestions you have, at an extra cost of about 10 quid in October compared to if I had the same CoP as Mr Fork, it's not the end of the world, it is annoying not understanding why though.