DanDee

Urban Plumbers never installed a buffer on their V installs

My question was rhetorical, Why say something so skewed just because someone else said it? No fact check?

To a refrigeration engineer that sounds like saying that a car in order to keep the same speed(or reduce it's input) down hill, instead of reducing the gasoline feed, it just goes into neutral or lower gear.

In all data sheets the rated output be that min/normal/max is always stated at the same 7outdoor/20indoor for A2A and 7out/35water or 55water. With other temp ratings specifically pointed out. I don't know where your -5 comes from. The lowest minimum output at lower temp also does not necessarily holds true, due to the safety minimum modulation of the compressor at freezing temps which is higher than at +7...+12. But spinning the compressor at the same speed will obviously put out more heat with every degree of outdoor increase.

Any details/data/document on this?

The excessive oversizing would indeed lead to both cycling and inefficiency. In heating mode a single wall split A2A will start cycling if the vane and fan speed are not set in a way that warm air output is not pushed as far as possible in the room, the air temperature around the unit rise faster that for example your case, where you will use a flow/return duct, that cycles the air around the house. Another issue with some units is the room thermistor that is seated on top or next to the condenser coil, where it reads a higher air temp than the rest of the room, triggering cycling. The inefficiency arises from the same effect of the air warming up around the unit, which reduces the heat transfer rate vs the production. Again having a central intake with outputs in different rooms can mitigate this, to an extent. In cooling mode(in countries where this is highly important) oversizing again triggers not only cycling, but the unit running less rather than continuously, it removes less humidity from the air, creating discomfort. So hobbyists have to find a ways to run the unit such that it blows the air away from the unit, use a ceiling fan and move the thermistor or find a unit where the remote is the room thermistor. Testing when the wife is not home. ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓

Make it think it is over 1.2bar

Can we agree it's a bit pointless to talk about HP not being suitable when talking about a house that is leaking that much? It's a bit aberrant. That house would have bigger issues before talking about the HP, and if you only talk about them when a HP is involved, then you failed at it already.

Skim through this topic https://community.openenergymonitor.org/t/vaillant-arotherm-owners-thread/21891/42 Summary The bottom line is that the COP from openenergymonitor / heat meter setup is pretty close to the built-in Vaillant COP figures (using both the Working Figures from the controller or using the raw data from Sensocomfort controller). So on this evidence, the built-in information on the Vaillant Arotherm Plus is likely good enough for most regular folk. Heat Meter COP: 3.39 Sensocomfort COP: 3.26 Controller: COP 3.2 heat (2.4 hot water) - AKA “Working Figure” But whilst the COP are around the same ballpark, we notice that the raw data from the Sensocomfort isn’t exact when compared to the heat meter. Electric Input (3% out?) Heat Meter: 647kWh Vaillant: 631kWh Heat Output (7% out?) Heat Meter: 2195kWh Vaillant: (1427+ 613) = 2058kWh But close enough for most people not to care? Hope this helps.

I need to re watch the video(I seen in the past, not today), I think the video was done with examples from other systems vs the one I mentioned(his current one). The system in my analysis runs very well when it comes to delivering medium to high output, very rare does modulate efficiently as expected for minimum output, but often starts to cycle due to the flow temp rising as a result of the system increasing the compressor speed at the time when the condensing temperature/pressure is on the rise anyway due to how the system manages the opening of the expansion valve(closing and opening at certain levels within whatever the parameters set in the system).

I do not have an answer for that.

In the brochure that I shared the link to, you have the outdoor unit with either 1 single indoor unit, 2 indoor units or 3 indoor units. The system with 2 indoor units having a better COP than the one with 1 indoor unit, but this only when they work in tandem. P.S. Yet it will be more efficient to run 2 separate systems, than one outdoor with 2 indoor(multisplit) if you need to run the upstairs and downstairs separate.

This is an example of how John's 6KW Ecodan, instead of running smoothly at minimum it chases its own tail in between compressor speed and expansion valve, continuously adjusting its opening until the system overshoots the target temp and starts cycling. With the cycle COP being lower due to the system pressure adjustment, and not being able to set itself to a fixed condition(or more constant).

The difference wasn't due to how cycling occurred, but due to how the heat pump manages its refrigeration cycle/pressure/expansion valve when it hits the steady state(target flow temp), in a particular range of flow temp from 29-30C to 34-35C. yet when the flow temp is rising from 20 to 35 at the start, that issue doesn't occur. Sometimes at the same flow temp during the same heating cycle there's no issue initially and then the issue starts. It happens even at 35-37C(rare occurrence). This shows how the issue temporarily occurs until the system finds its happy medium at the bottom range output of the HP.

That's the noise of what it means to import 50% less gas from Putin, get used to it. Treat it like kids noise, be them yours or someone else's.

Rebranded Chinese Midea(already on the market) https://www.elettronew.com/en/prodotti/categoria/clivet-heat-pumps-2149.html https://barillafuture.com/collections/clivet-single-fan-ashps

https://heatpunk.co.uk/ (You can also find a copy of the Freedom Toolkit - spoken of below HERE and the JS Harris sheet can be found HERE. Ed)

The flow meter/sensor needs cleaning as well.

That's a weird way to state the details of the coil, so both .4m2 and .8m3 cylinders have been sold in the past with HP's from the whole range of 4kW to 16kW. Does that mean is it worth buying and using today? Can you buy it/use it and give the forum the verdict?😁 https://www.daikin.ch/content/dam/document-library/installation-manuals/heat/air-to-water-heat-pump-low-temperature/ekhwsu-b3v3/EKHWSU-B3V3_4P344370-1B_2019_08_installation manual_English.pdf

That doesn't happen anymore since the HEX version

From mitsubishi, both same compressor size. the AC loses efficiency due to the length of line set, both by losing temp and higher workload to achieve the same condensing pressure the A/W has a compact refrigeration system, bigger evaporator, refrigerant receiver to optimize the unit The AC is sold world wide, the A/W not so much. £1.5K vs £2.5-3k

That's when you use the hot water from the tank.

https://www.goodenergy.co.uk/blog/how-we-know-our-heat-pumps-outperform-others/#:~:text=At this level the average,average performance across all seasons