I have a hydronic heating system (aka. radiant floor heating) – basically house gets heated by pumping heated water through tubes under the floors or small radiators. It’s supposedly a closed system but it includes an auto-topoff from domestic water and a venting system for releasing air bubbles that includes some evaporative losses. Plus there’s the risk of leaks .
I’d like to add a passive sensor to measure the amount of water flowing into this system from the auto-topoff, and, of course, I’d like that measurement to make its way into Home Assistant so that I can track it over time and/or set warnings.
Here are my setup/constraints:
I don’t want to break the bank. A few hundred dollars is ok; a thousand is not.
I’d prefer a meter that doesn’t require cutting the pipe but can add one if needed. The pipe is 3/4"
Communication via Wifi or Z-wave. Nothing that depends on a 3rd party cloud server that might be gone in a few years. I don’t (yet) have zigbee or thread setup…
I do not need – or want – an auto-shutoff. I’ll make my own shutoff decisions thank you very much. This rules out the “Moen FLO” type of thing (as does the cost)
I do apparently have THIS meter currently installed which includes a pulse output. However I have no idea if it is calibrated or accurate.
I really do not want to build a home-brew solution – e.g., nothing that depends on writing my own YAML for a general-purpose ESP32 etc. based on vague incomplete instructions from some random internet site (sorry too many bad memories). Additionally, I have no way to calibrate or test the calibration of whatever I produce: how many pulses from the existing meter equals a gallon? Is my pulse meter double counting? etc.)
I think you choose wrong approach trying to measure the water added to the system. If there are no leaks, the quantity is so minimal that it’s hard to measure and since you exclude calibration, maybe impossible.
Auto-topping likely uses pressure sensor and that’s likely best approach for you to get indication if there are problems. Either measure pressure or try to detect when the auto-topping valve opens and closes.
I have a pool with an auto-fill and my water sensor (Flume) does not detect when the mechanical refill valve is open because it’s only a very small volume per minute that gets through.
After I backwashed the pool filter (approx. 60gal) the sensor will tell me that there is a ‘leak’ for about two hours - so, in principle, this works.
But the normal top-up flow is just too little to be recognized - even during hot Arizona summers.
The only thing I can think of is to install a separate physical (sub-)water meter like the one you’ve linked to. But even then, it might take quite a while until a sensor recognizes anything, except in a catastrophic scenario.
I did the calibration that their app suggests. Very limited test, but I filled a 2 gallon container and calibrated with that. I then ran 1, 2 and 8 gallons and it was very close. I was going to compare to our city water meter but the Droplet is downstream from outdoor faucets that get used frequently. And I’m not sure what good being accurate is as challenging the water company probably wouldn’t work out for me. I’ll try and compare to the meter over a few days and comment again.
If you already have a meter installed and measuring the value you want to track, just set up an ESP32 cam and use AI on the edge to digitize it and make it available to HA. This is how I track my whole home water usage.
I also have floor heating like that. My system does not replenish water by itself, I have to open a valve to do this.
From experience I can tell it’s barely any water at all. I have to open the valve at most once per year or two and keep it open for a few seconds.
If you are worried about a leak (which I think is really really unlikely after the initial tests went well), perhaps you can just turn off the automatic top-off. There’s probably a valve in there on the input pipe. Then you can observe the pressure in the system (in my case this is displayed by the heater, I would expect something similar in your system).
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(sorry too many bad memories). Additionally, I have no way to calibrate or test the calibration of whatever I produce: how many pulses from the existing meter equals a gallon? Is my pulse meter double counting? etc.)
I’ll try and compare to the meter over a few days and comment again.