MyHeatpump app: Automated detection of heat meter air error

I’ve added a feature to display an error on the MyHeatpump app if the heat meter air issue is detected in the data. There are two modes:

Automated error detection

E.g on system 266, https://heatpumpmonitor.org/system/view?id=266:

This flags an error if the following conditions are met:

  • electricity consumption is more than 200W
  • heat output is 0W
  • DT between flow and return is more than 1K
  • there is at least 60s of error state in each error period.
  • flow temperature is at least 30C

Error flag based on heatmeter error register

The axioma heat meter that we now supply as standard provides an error register that we can use to detect this issue. The error register is recorded to a feed called heatpump_error which is then configured for use in the app:

image

The axioma is a little more conservative in when it flags the error, e.g it didnt flag the error until a few minutes later compared to the automated conditional detection method above.

Axioma flag:

Automated detection:

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Hi Trystan,

My system now shows a data error.

I don’t think I have a data error though!

It is just the normal pre-heating of the compressor in my Daikin heat pump.

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Thanks @matt-drummer. I checked for this on Colin’s and couldnt find good examples, thanks for noting it on yours! I’ve change the conditions to require:

  • DT: 1.5K
  • At least 2 minutes of error state.

That seems to have cleared it on your system. Will refine until I get this right.

Thanks Trystan.

Maybe you need water flowing to detect an error?

Unfortunately you get both flow rate = 0 and heat = 0 during this error state…

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Of course, I didn’t think before I typed!

I’ve changed the implementation slightly to require a minimum error period of 60s and a minimum flow temperature of 30C and added a visible note with link to documentation Removing Air from Heating Systems — OpenEnergyMonitor 0.0.1 documentation when you open the show detail section:

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Can you check mine too, Ta Sean

Hello @Heatsave you had the issue on your first hot water run but it seems to have cleared after that? Did you do anything to sort it?

Love this - we’ve never looked at the time lag between detection and flagging the status in district heating applications, and now are the criteria documented - thanks!

@TrystanLea thanks for this- a great feature. Does it also exclude the erroneous data from the overall COP? I constantly have this problem at the end of my hot water cycle despite trying to clear the system of air. Think I may need a deaerator.

No not yet. While I’m pretty confident in the error detection capabilities , I’m not 100% confident yet to the point that I’d want to start automatically excluding electricity data at those points. It’s probably best to use it as a flag to notify of the issue for now.

Errors can now be highlighted on the daily summary view, and interestingly I have 14minutes in my 4 and a bit years of data with the conditions met to trigger this flag, even though I have a sontex heat meter.

See little red dot in the middle:

Clicking through to that day (Im not sure what went wrong there)

See my dashboard here: Emoncms - app view dashboard

To see errors in historic data the daily summary data needs to be recalculated. I need to make a button for this…

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Another example of daily view showing lots of heat meter error time, system: https://heatpumpmonitor.org/system/view?id=296

I haven’t been through all systems to recalculate the error history yet, so this will not automatically show for all systems until I have done that.

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I’m a little confused by this.
Expanding out to 1week shows “air issue detected for 5mins”, but when I try to zoom in (or out) I can’t find where this is being flagged. Is this “spurious” error detection going on or is there really something I should be looking out for in more detail?

Probably spurious, as you zoom out, interval of each data point is longer and that seems to be circumventing my checks. Will test on your dashboard and see what’s needed to avoid.

Oh will be interesting when mine is processed as I’ve had that issue in the past.

There you go: :slight_smile:

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Excellent, thanks.

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Can you detect when immersion is running, and not present it as an error? Maybe even correct for the missing heat?

Emoncms - app view

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