Oil tank level sensor?

I'm looking for a sensor to monitor the level in my heating oil tank.

There are a couple of solutions that keep coming up but they are all hard linked to some vendor's cloud platform that isn't open AND they want to charge me a monthly charge to use them... and at some point no doubt they will end the service (knowing cloud only too well!)

I am after being able to track reasonably accurately my heating oil use - a level sensor would be fine, I don't need a metering one on the outflow.

Anyone done this before?

Thanks in advance!

Always good to search the SmartThings community too. This might work:

2 Likes

I was considering the same, however for oil volume. Not usage (at least not in detail).

For you goal you might consider measuring burner on time.

I have a couple sensors measuring water tank levels using an ultrasonic sensor with arduino board and hubduino. Built a custom device handler to let you know the percent full it is. But takes a bit of tinkering to build the sensor.

Thanks @ritchierich but thats a bit heath robinson for me - or rather I'd be no good at building it!

@johnrob burner on time is a good idea - how would you measure that? I guess the consumption rate is flat so it is a good call.

@kampto yes I actually have an ultrasonic sensor that displays remotely. However its a dumb device that just shows a LCD display with 10 bars of fill level. The cloud metering solution I mentioned is the same device but with some sort of wifi module plugged into it. Reading reviews its hardly stellar and costs a lot of money.

I use smart oil gauge (https://www.smartoilgauge.com/) and I wrote a driver to pull from their web interface. It's a bit rough, but it works. I haven't had time to clean it up and post it but I'm happy to share it. Also not sure its available outside the US.

It's a bit fragile as it depends on them not changing their login logic. I've captured their iOS app flow and may switch to that at some point.

The ultrasonic sensors are somewhat inaccurate above about 80%, so you'll see fluctuations.

I also have a water tank and use a pressure sensor (https://a.aliexpress.com/_mORqGeM) which works really well with a Shelly uni. I would think it would work in this case as well, however I haven't researched it and putting even small voltage into an oil tank seems like not a great idea...

1 Like

Your intuition is correct, however its not as bad as it seems. I still don't recommend it for a hobbyist.
Automotive diesel ( and I assume home heating fuel) can become stochiometric between 20 and 25 °C. When stoichiometric there is a finite amount of energy needed to initiate combustion. If the energy allowed into the tank is below the required level the design is intrinsically safe.

Regarding the pressure sensor. My first thought is the bottom of a fuel oil tank is full of sludge and may be tough to keep a pressure tube clear and empty. However I was thinking of my system and I could put a pressure sensor at the filter tap. I might have to only take readings when the burner is off but it may be easier than building an ultrasonic sensor.

1 Like

I think after a lot of thought and some of your comments that the best bet is to try and detect the boiler firing, record that and do some maths on the flow rate of the nozzle.

Not quite sure how to pick up the firing though - although I had planned to use a zwave room thermostat to trigger the heating (or rather use the receiver part for HE to trigger it based on other sensors) that still leaves the hot water that could call for boiler ignition.

Maybe a power use sensor on the mains cable to the boiler itself?

While it think this is the best approach, sensing is problematic.

I'm an engineer so my options are braoder than most. If your comfortable with circuits pls let me know.
Otherwise you might try this current sensor module.

I've never used one of these but they would seem to fit the bill. I would guess the output contacts could go to a contact sensor with provision for external contacts.

Another thought that would not use your HUB. You might consider a timer. Search Amazon for "elapsed time meter". One of these with the above sensor will simply cumulate burner time. I realize it won't have a fancy Hub interface but it will work and it is non invasive to the burner.

John

Below is data from my boiler. Data taken with a custom DAQ setup, recording only when something has changed. Perhaps it will help you get a feel for what you will be getting.

Firmware Version:  Ver: RC13							
							
Creation Date - Time: 2020-2-16  14:36:48							
							
Δ seconds	 Temp °C	 Burner	 Circulator	 Aquastat	 Level 1	 Level 2	 Level 3
5	80.5	0	0	1	0	1	0
9	80.75	1	1	0	0	1	0
124	81.25	1	1	0	0	0	0
161	82.75	1	0	1	0	0	0
162	82.75	0	0	1	0	0	0
162	82.75	0	0	1	0	0	0
724	86.25	0	0	1	0	1	0
769	86.25	1	1	0	0	1	0
964	89.5	1	1	0	0	0	0
1016	92	1	0	1	0	0	0
1016	92	0	0	1	0	0	0
1016	92	0	0	1	0	0	0
2664	84.25	0	0	1	0	1	0
2731	81.5	1	1	0	0	1	0
2864	76	1	1	0	0	0	0
2869	76	1	1	0	1	0	0
2911	75.5	1	0	1	1	0	0
2911	75.5	0	0	1	1	0	0
2911	75.25	0	0	1	1	0	0
2983	75.75	1	1	0	1	0	0
3377	84.25	1	1	0	1	1	0
3449	80.75	1	1	0	1	1	1
3617	72.25	1	1	0	1	0	1
3694	69	1	0	0	1	0	1
3750	68.75	1	0	0	1	0	0
3880	75.75	1	1	0	1	0	0
4563	92.5	1	1	0	0	0	0
4583	93	0	1	0	0	0	0
4616	94	0	0	1	0	0	0
4616	86.75	0	0	1	0	0	0
7251	91.25	0	0	1	0	1	0
7333	90.75	0	1	0	0	1	0
7371	90.75	0	1	0	0	0	0
7404	90.5	0	0	1	0	0	0
7405	90.5	0	0	1	0	0	0
8622	83.5	0	0	1	0	1	0
8690	83.25	1	1	0	0	1	0
9219	84	1	1	0	0	0	0
9282	86	1	0	1	0	0	0
9283	86.25	0	0	1	0	0	0
9283	86.25	0	0	1	0	0	0
10759	91	0	0	1	0	1	0
10823	90.75	0	1	0	0	1	0
10979	90.5	0	1	0	0	0	0
11030	90.25	0	1	1	0	0	0
11031	90.25	0	0	1	0	0	0
12119	87	0	0	1	0	1	0
12176	86.75	0	1	0	0	1	0
12315	86.25	1	1	0	0	1	0
12339	86	1	1	0	0	0	0
12391	85.5	1	0	1	0	0	0
12391	85.5	0	0	1	0	0	0
12391	85.5	0	0	1	0	0	0
13479	83.75	0	0	1	0	1	0
13560	83.25	1	1	0	0	1	0
13721	84	1	1	0	0	0	0
13769	85.25	1	0	1	0	0	0
13769	85.25	0	0	1	0	0	0
13769	85.25	0	0	1	0	0	0
14097	88.5	0	0	1	1	0	0
14190	87.75	1	1	0	1	0	0
14861	81	1	1	0	1	1	0
15081	81.25	1	1	0	1	0	0
15362	88.75	0	1	0	1	0	0
15521	86.5	0	1	0	0	0	0
15521	86.75	0	1	0	1	0	0
15532	86.5	0	1	0	0	0	0
15581	84	0	0	1	0	0	0
15582	76.75	0	0	1	0	0	0
15582	86	0	1	0	0	0	0
15583	85.75	0	0	1	0	0	0
15583	85.75	0	0	1	0	0	0
16126	86	0	0	1	0	0	1
16200	85.75	0	1	0	0	0	1
16426	83.75	0	1	0	0	0	0
16437	83.25	1	1	0	0	0	0
16481	81.25	1	0	1	0	0	0
16481	81.25	0	0	1	0	0	0
16481	81.25	0	0	1	0	0	0
16624	69	1	0	1	0	0	0
16931	74.5	0	0	1	0	0	0
21832	68.5	1	0	1	0	0	0
21945	69	1	0	1	0	0	1
22056	76.25	0	0	1	0	0	1
22058	76.5	1	1	0	0	0	1
22246	86.25	1	1	0	0	0	0
22289	86.75	1	0	1	0	0	0
22289	87	0	0	1	0	0	0
22289	86.75	0	0	1	0	0	0
25416	68.75	1	0	1	0	0	0
25635	58.5	1	0	1	0	0	1
25736	59.5	1	0	0	0	0	1
25805	60	1	0	0	0	1	1
25925	60.75	1	0	0	0	0	1
25935	61	1	0	0	0	0	0
25972	61	1	0	1	0	0	0
26430	69.5	1	0	1	0	0	1
26483	70.75	1	0	0	0	0	1
26730	72.75	1	0	0	0	0	0
26778	75.5	1	0	1	0	0	0
26803	77.75	0	0	1	0	0	0
27367	86	0	0	1	1	0	0
27483	81.5	1	1	1	1	0	0
27483	85.25	1	1	0	1	0	0
27632	85.5	1	1	0	1	1	0
27764	71.5	1	0	0	1	1	0
27940	72.25	1	0	0	1	0	0
28300	75.75	1	0	0	1	1	0
28500	78.25	1	1	0	1	1	0
28535	77.5	1	1	0	1	0	0
28590	69.75	1	0	0	1	0	0
28829	76.75	1	1	0	1	0	0
29300	86.75	1	1	0	1	1	0
29460	89	1	1	0	1	0	0
29502	86.5	1	1	0	0	0	0
29503	86.5	1	1	0	1	0	0
29504	86.5	1	1	0	0	0	0
29504	86.5	1	1	0	1	0	0
29509	86.75	1	1	0	0	0	0
29551	87.75	1	1	1	0	0	0
29555	88	1	1	0	0	0	0
29584	82.75	1	0	1	0	0	0
29584	83.5	0	0	1	0	0	0
29584	87.75	0	0	1	0	0	0
29585	88	1	1	0	0	0	0
29586	88	0	0	1	0	0	0
29586	88	0	0	1	0	0	0
31720	79.75	0	0	1	0	0	1
31809	79.75	1	1	0	0	0	1
32020	81	1	1	0	0	0	0
32063	82.75	1	0	1	0	0	0
32063	82.75	0	0	1	0	0	0
32064	82.75	0	0	1	0	0	0
32871	82.25	0	0	1	0	1	0
32950	82.25	1	1	0	0	1	0
32998	82	1	1	0	0	0	0
33026	81.5	1	0	1	0	0	0
33027	81.5	0	0	1	0	0	0
33027	81.5	0	0	1	0	0	0
34898	73.5	0	0	1	0	1	0
34974	73.5	1	1	0	0	1	0
35201	78.25	1	1	0	0	0	0
35240	80.5	1	0	1	0	0	0
35241	80.5	0	0	1	0	0	0
35241	80.5	0	0	1	0	0	0
35329	84	0	0	1	0	0	1
35422	85	1	1	0	0	0	1
35422	85	1	1	0	0	0	1
35630	82.5	1	1	0	0	0	0
35687	76.5	1	0	1	0	0	0
35687	76.5	0	0	1	0	0	0
35687	76.5	0	0	1	0	0	0
35921	76	0	0	1	0	1	0
35967	76	1	1	0	0	1	0
36161	71.5	1	1	0	0	0	0
36209	71.75	1	0	1	0	0	0
36209	71.75	0	0	1	0	0	0
36210	71.75	0	0	1	0	0	0
36234	74	0	0	1	1	0	0
36328	77.25	1	1	0	1	0	0
36813	76	1	1	0	1	1	0

Thanks @JohnRob

I read someone's blog that said about using the elapsed time meter approach. Its a good approach but being less of an engineer and more of a computer geek I sort of wanted to push for a digital solution.

What about one of these clamp type sensors on the power cable to the boiler?

But a timer is digital :slight_smile:

Remember you only need to measure ON Time.
I suggested the non contact current current switch because personally I would not break the burner wiring to pass it through a low cost device.

An engine hour meter that accepts line voltage is what I've used in the past. Your burner nozzle and oil pump pressure will give you the flow rate. Then multiply that by your hour meter. This is a dumb setup but works.

The last time I had to deal with an oil furnace was in my parents' home 50 years ago. I know the oil delivery companies estimated oil usage using a calculator for heating degree days based on average daily temperature readings. In the US and Canada that data is readily available and there is a calculator that makes the estimation quite easy. I do not know if the UK has something similar. Once you determine the historical fuel oil usage for your home, it is easy to estimate when you need to refill the tank.

Still trying to figure out how this works and how applicable it may or may not be to a fuel oil tank application....but it says it is.

image

This could work whenever it comes out (been a while since it was announced, says Fall 2022 but I doubt it since 2022 is almost over), but you will need to buy the FLRG48 float level gauge that Sinope will sell for use in fuel tanks. Might want to reach out to them and ask more details and ETA?

1 Like

That looks exactly like I want!

Not sure its available in the UK, but should be able to import it.

It even says on their page that its HE compatible!!!

1 Like

You could search Sinope patents.

1 Like

Download the Hubitat app