joth

I think there's been 3 reports of ecodans. @joth is seeing reliable 5.5W average standby load (266 Wh consumed in 48 hours). I have high confidence in this figure, as 2 different CT clamp arrangements agree (one dedicated on the ASHP, and another pair measuring grid import and household "indoor" consumption) @LA3222 is seeing 200W continuous standby draw. There was a comment that "To be honest I haven't scrutinised the system too much." and "Not sure how accurate the readings are that I'm getting", so I'm not sure of the confidence here. @Kenway is seeing 300W standby. They appear confident in that number, however I'm a little suspicous of the line chart showing kWh plotted against hours (is that kWh per hour, or extrapolated to per day, or something else? kWh is a quantity of stuff so this should be a stacked bar chart to make mathematical sense, not a line chart) We certainly could use another few readings. I have a friend with one, I'll ask them.

🙂 I don't care much about KwH vs kWh etc, but W vs Wh is a very important difference. It's like asking someone "how far is it to Scunthorpe?" and getting the reply "yesterday I did 45 mph"

Does it have to be the wall of the house, or could it be the wall of an outbuilding? Perhaps a small outbuilding, that's not yet been fully built.

I think you mean it consumed 313 Wh across the 24 hour period.

Yes the vampire load is very variable on my ecodan. After operating for 30mins at 11am yesterday it as dormant until 5pm, had 3 blasts of 25W and then dormant again until 3am. So ignoring the actual operation, the energy accumulator says the background load has drawn 124 Wh in the last day, giving an average background load of 5W. Not perfect, but low enough not to worry about. If the OP really is recording 200W average I think the unit has a fault. Mitsubishi tech support need a slap. (I had the same challenge with a Sony AV amp. A firmware update suddenly pushed the background draw from 1W to 60W. As a consumer I seemed to have no recourse for such a fault, even though it's illegal under the EU 1W regulations)

One more finding: I ran the DHW for 30mins at 11am this morning (reheated the tank right up to 55C), and the periodic 27W draw ceased for the following 5 hours. I presume as the compressor was nice and hot it didn't have any need for warming it up. Thus, the draw would appear to be dynamic based on environment and operational conditions, not a static invariant load.

It doesn't 😞 (Hence why I had this one spare, I'd replaced it with an emonpi for import/export measurements) There's a hack published to allow reading power direction, but I backed away from trying it. https://github.com/apreb/eNode#measure-direction-hack-

Very early days, but what I'm seeing with a dedicated CT (pzem-004t v3) is it alternating between 3W and 27W on a 30 min cycle, so maybe averaging 15W continuous. This is for a PUZ-WM85VAA with FTC6 controller.

I don't understand this graph, as it's plotting kWh against time. Is that kWh per hour? Also known as kW (averaged over an hour). If so, yes that does seem to be 300 W 😮 I've just put a dedicated CT clamp on my ecodan and it's happily drawing 3.7W. And it's been below 5ºC overnight. Something fishy going on here. I'll leave mine logging add day, and force heat some extra DHW later once PV is going, and see how the power profile looks.

All the best plugging a 32A heat pump into a tuya wall socket 😅

Depends what you call peak months. For the half year March - August, we exported over half generation on an 8kW array, and that's with a full home automation system working to maximize load shifting as far as I can. I expect with 12kW it would be an even higher % going unused.

That's 200W. And I guess 24/7 is unitless 😂

Fascinating. Do you have freeze-stat disabled? What is the outdoor temperature when it's drawing it? I will put a dedicated CT on mine just to confirm...

Which version? our monobloc puz-wm85vaa doesn't seem affected.

I'd be interested in the model number, as our monobloc puz-wm85vaa doesn't have this phantom draw. Looking at the databook it appears the ecodan monoblocs have "hermetic twin rotary" compressors whereas the split units "hermetic scroll" compressors which sounds like it would make a difference. The explanation from mitsubishi tech support is shocking though.

Funnily enough it was mentioned exactly 5 years ago by SteamyTea in this very thread.

I'd assumed ESHP was a typo for EAHP: Exhaust air heat pumps https://energysavingtrust.org.uk/advice/exhaust-air-heat-pumps/

I was thinking if combined with the "bonded rails" approach as per PeterW but I'm no expert.

Really OT side point: rotary heat exchangers are found to be prone at transferring airborne viruses from extract back into the supply air stream and should be disabled (bypassed) in the event of a, say, a pandemic. Enthalpy heat exchangers do not have this limitation, but also recover humidity/latent heat. (Guess who was selecting their MVHR in April 2020)

Another scenario is you have 12kW array installed but the only 10kW is approved in the G99 (let's say). So you could put all the panels on a 10kW inverter and that would probably be fine, or you could hold a few panels back to make another string to put on a DC battery charger to run DC loads from (I had this as my plan B, as the home automation and most the lighting is 24V)

What does PVGIS say? https://re.jrc.ec.europa.eu/pvg_tools/en/ A link on here to an eBay listing. No a lot though? ours was included in the supply& install price so I don't even know what it was, but nothing compared to the £3000 it would have cost us to go 3ph So decide the plan assuming export limitation, but put a G99 for it anyway as it will give you more "future proofing" if it is accepted. It may vary by inverter, but with solaredge you have to buy additional hardware to enable export limitation. Also, it will limit your choices to just those inverters your DNO recognises as being allowed for export limitation. And no I don't believe you can install and notify under a G98 route I think having>3.68kW inverter with export limitation still needs a G99 and permission in advance anyway, but others may know differently.

Rather adding redundant insulation can't you increase the screed thickness instead?

You'll never self use the full capacity of 12kW array, even with a battery, so personally I'd go MCS and G99 and attempt to get payment for anything unused. With a 8kW array we get about £250/yr in exports. A well oriented 12kW array could get double that, depending on self usage. And that's before any future price rises. There was a listing the other day for a self install system with the option of a MCS cert for and extra £345. If the G99 is rejected then 3ph or export limitation is plan B and C, but either of those cost more than the G99.

As that's 40W I guess it's incandescent rather than LED? If you're feeling cavalier, how about rewire the fitting to put both those bulbs in series?

Effective cooling via air requires (much) higher air flow rates than MVHR uses, so it's better to have independent "recirculating" air cooling device rather than use the MVHR for it. I've fitted a Fan coil unit (FCU) to the ASHP cold water supply in order to cool one bedroom. It works well, but does need a much larger buffer tank than the UFH system was specified with.