I’ve made a unit to read the temperature of outflowing and return water, and whether the boiler is being demanded. This is then sent to HA via MQTT.
I also wanted to add a sensor to detect when the boiler was actually fired up. I was hoping a reed switch on the solenoid (what turns the oil on) but the magnetic field does not operate the reed switch. I guess it’s engineered to keep the flux internal.
Short of cutting into some of the mains cabling (ie, from the internal thermostat, or the power to the solenoid itself, which I’m guessing is also mains!), has anyone got any suggestions?
I don’t think a tilt sensor would work as nothing visible moves.
I was wondering if some sort of microphone or accelerometer with a threshold set appropriately might work, but i’ve never used them. Maybe I’ll ask on the Arduino forum.
Split current transformer on the blower leads (well, just one technically) You’ll have to open the control box probably, but it’s not that intrusive. Or, on that 24VAC solenoid, but it will have to be AC to work. It’s the current, not the voltage that matters.The ESP32 has a ADC that will read a current clamp no sweat, especially with the emon library. Use ESPHome. It’s very versatile. You may have to tune the burden resistor to get the best results, just be aware that when the motor kicks on it will pull a surge and could easily over-volt the ADC if you have too large a burden resistor. There are many ways to skin this cat.
Tom
Yes, I’ll get one. I’d been thinking of designing something along those lines but wasn’t feeling that brave. Here in the UK I’m guessing that it is 240V AC not 24VAC as other posters have suggested. I will check that out though.
It does mean I have to break the cable - just not sure what the service engineer will make of it!
Thanks
You shouldn’t need to cut any wires if the solenoid cabling connects to screw terminals somewhere. Just connect the optocoupler or relay in parallel across the same terminals.
Thanks for opening this topic! I’m in the "thinking process of the same quest, only this is for a house in Switzerland, also using oil burners for the heating. The way I was thinking to approach was:
Measure the power usage?
When the burner is active it does use more power then when it’s idle. The water pump of the hot water will have a different pattern then the heater oil pump and blower that is on… (A thought not actively researched yet)
Measure the power usage I was thinking either by using a wall socket switch that measure power consumption… problem here is its a swiss so hard to find…
Since the heater is on a single Fuse i was thinking of measuring power consumption on the wire in the fusebox with ( SHELLY EM power clam)
The protocol of the heater sends out when its on or off, it’s a sort of S0 bus protocol,
I’ve bookmarked it but did not further researched it yet.
The noise in the room.
When our heater is “on” it makes a lot of noise compared when it’s off. So by measuring the noise in the room was an alternative way also in case everything else fails.
Opening up and adding wires to the heater
mnnaa as you mentioned as well not sure what the insurance and mechanical engineer might think of that when the drop by for maintenance or checkup
==== Measuring the level in the Oil Tank…
I have been looking of ways to do this “save” but so far on a dead end if it comes to fitting solutions…
The way I was thinking of this is:
Measure oil consumption over a period of Burning hours. My guess is that the burner will use approximately the same amount of oil per hour burned. In other words if it burned for example 100 hours the tank is almost empty.
All other solutions like measuring oil flow or liquid level, sound easy but not in a system that is closed and not ment for an end user to make modifications on.
I’m sure many people would be interested in monitoring their boiler.
My problem is that I have no power available at the boiler, other than when it’s being demanded by the hot water or central heating. It’s also quite a way from my router so I’ve had to use a ESP8266 as a repeater (it’s on github).
The ESP8266 at the boiler is a WeMos dev board with integrated battery and charging.
I’ve written a sketch that uses 2 TMP36s to measure the out and return temperatures, powering each up seperately for just a second using 2 GPIOs as outputs and feeding the output voltage to the ADC. That seems to work OK without the 2 interferring with each other.
I’ve also found a point on the dev board where the voltage goes high when it’s under power and I’m reporting on that and using it to wake the board up from light sleep - to save battery drain (particularly in the summer) I send it into light sleep after an hour of no demand. The rest of the time I take readings and publish every 30s or on a change.
I wanted to read the burn state to determine when a refill was near (after some calibration), but am still working on how to sense that, probably by the gadget suggested by Tom.
If I was starting again, I would now use a digital thermistor that sends the temperature to a digital input pin as they can be wired in parallel. I would also think about using the 3 port 240V opto isolator which is available to detect demand, boiler thermostat demand and burn. I could then detect a fault if the boiler thermostat was demanding but no burn.
Anyway, I’ll keep at it.
Since my last post above, I had to change the boiler as the old one had rusted away and started to leak!
I’ve updated my monitoring of temperatures to use 3 digital thermometers (DS18B20, outflow, return and cabinet), and am sensing Demand and the boiler’s internal thermostat demand. The new boiler’s oil solenoid is inaccessible so I’m not logging that. To compensate I just deduct 8 seconds from each burn time to account for the delay between the boiler thermostat demand and the boiler actually firing up.
Within HA I’ve got several entities that provide the price, flow rate, boiler rating etc and have got some Lovelace cards, Graphana graphs and the Energy integration set up. Here are some screen shots…
One night I had the same idea. I checked my boxes to find out what I could use.
I have a Finnish made Oilon burner, which gives 230VAC output when burner is on. I had some spare AC/DC transformers, some car relays and few cheap Aqara sensors.
So, I made on the spot an arrangement, where the burner 230VAC was fed to transformer outputting 12 VDC. To that I connected a car relay and on the relay I taped Aqara magnet operated door/window zigbee sensor to sniff the relay coil. I already had a Conbee II -powered zigbee network running.
Of course I could also use the burner internal solenoid, but did not bother opening the housing and try…
Quick and dirty just for testing, but it worked and it still is there…
Thinking of doing something similar to be able to measure when the burner is on. Has anyone tried an Aqara vibration sensor? Does anyone have any reasons why this would be a bad idea or any reasons as to why it wouldn’t work?
