I am using Heat Pump monitor with a Vaillant Arotherm Plus. I’m running Home Assistant and have both the MyVaillant and EMONCMS integrations running perfectly. Heat Pump monitor appears to be using a feed from the met office which isn’t very accurate for my location, sometimes a difference of up to 3C. 1) How can I check if the met office data is actually for my post code, 2) I would like to replace the met office feed with the data from physical Vaillant external sensor which appears in the MyVaillant integration. I thought someone may have already done this but I’ve had a quick search of the forum and couldn’t find anything. Apologies if this is already documented. Is anybody else doing this and if so how?
Hi Mark,
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Based on responses to similar questions in the past, I believe @glyn.hudson is the expert on the emoncms.org MetOffice API so he’s probably best placed to advise on how that’s been set up for your system and whether the location it’s using could be tweaked to make it more accurate.
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It’s certainly possible to use your own outside temperature measurement instead of the MetOffice data, since that’s what I do. An important step is connecting the
heatpump_outsideTField in the “My Heatpump” app to a suitable emoncms.org Feed that is populated from your Vaillant sensor. It looks like you’ll need the Emoncms History integration to be able to Send data from HomeAssistant to Emoncms.
In my case, I use a standalone Python script to push readings obtained from a variety of local sensors directly to the emoncms.org API, but if you’ve already got HomeAssistant receiving data from MyVaillant you might as well use HomeAssistant to manage the data flow for you.
David
Yes, that’s correct outdoor data is from a metoffice API based on the postcode.
There may sometimes be a difference between what the Vaillant sensor reads and the metoffice data. Often the Vallant sensor will report a degree or two higher, this can be becuase the Vaillant sensor is mounted on the side of your house, so it will be getting a bit of heat from the structure of the building. It also maybe subject to solar gain. It’s actually quite difficult to get an accurate local true air temperature reading. On the whole we’ve found the metoffice data be be prerry good.
Yes spot on, you can use your own data for outdoor temperature if you want. Once the data is in Emoncms you can select the new Feed in the MyHeatPump app
I had wondered if this is actually the better value to measure? This is the actual environment that the heat pump is operating in, rather than what the temperature is at a weather station X miles away from the heat pump?
I agree, an accurate local air temperature reading would be best. But as I mentioned, getting a accurate actual ait temperature reading is difficult. There’s a good chance the Vaillant sensor is not accuracy reporting the actual air temperature being drawn in by the heat pump since the sensor is being effected by the heat from the house. But assuming the Vaillant sensor is not affected by sunshine it might be the best value to use in this situation.
Hi folks, thx for your input. My external sensor is well positioned on North aspect, the only time it gets sunlight is early morning and late evening at the peak of summer which isn’t an issue. I want to use the Vaillant sensor as I live in an exposed area and whilst the met office data is generally good the local temperature can sometimes vary a few degrees. Does anybody have any sample scripts for taking the MyVaillant sensor data in HA and populating Emoncms
It should just be a case of checking what name your Vaillant sensor is showing up as in HomeAssistant then adding that name to the whitelist in the configuration file for the emoncms_history integration.
There are a few other threads relating to emoncms_history that might be useful - see e.g.