Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Oil boiler

Wed Nov 21, 2018 9:22 pm

Hi all,

I want to know how much oil my boiler is burning on a daily basis.

If my boiler is switched to stay on for day six hours, I would like to know what proportion of this time it is actually running and burning oil.

When it is running and therefore burning oil, there is an electromagnetic solenoid valve (240 volt) which is energised so I could take a feed from this and then monitor how long this is powered for.

My questions are:

Will the Pi be able to do this and if so, how would the data be collected?

drgeoff
Posts: 9739
Joined: Wed Jan 25, 2012 6:39 pm

Re: Oil boiler

Thu Nov 22, 2018 7:23 pm

No RPi model is capable of directly sensing (more than once!) the presence of 240 volts ac. You will need an interface circuit or device to produce an input to the RPi which is safe for the RPi itself and safe for human life, animal life and property in the surroundings. You will also need an understanding of the safety aspects in order not to compromise them. From what you have written so far, I cannot "give you a pass mark" on that. Can you allay the doubts of potential responders?

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Thu Nov 22, 2018 7:27 pm

Thanks for the reply but I’ve not yet actually ch3cked the line voltage from the control relay to the solenoid valve and for all I know, it could be 12v dc.

As I’m very new to these, what device would you need to send voltage to the RPi?

drgeoff
Posts: 9739
Joined: Wed Jan 25, 2012 6:39 pm

Re: Oil boiler

Thu Nov 22, 2018 7:34 pm

Lusk wrote:
Thu Nov 22, 2018 7:27 pm
Thanks for the reply but I’ve not yet actually ch3cked the line voltage from the control relay to the solenoid valve and for all I know, it could be 12v dc.

As I’m very new to these, what device would you need to send voltage to the RPi?
Establishing the solenoid voltage and whether AC or DC is rather fundamental before suggesting a device.

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Thu Nov 22, 2018 8:28 pm

Thanks and having checked, the solenoid is 12v dc.

I would also like to record voltage at a switch which is 240ac.

boyoh
Posts: 1316
Joined: Fri Nov 23, 2012 3:30 pm
Location: Selby. North Yorkshire .UK

Re: Oil boiler

Thu Nov 22, 2018 9:29 pm

If your oil burner as a flame inspection window, you could use a simple
LDR /opto isolator circuit to switch a 3.3vdc to your Pi in/put .It will be a
Non intrusive to the boiler supply The Opto isolator will give you total
Isolation from the boiler mains .

Regards BoyOh
BoyOh ( Selby, North Yorkshire.UK)
Some Times Right Some Times Wrong

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Thu Nov 22, 2018 9:34 pm

That’s an elegant way of doing it and whilst I’m sure it doesn’t have that option (aside from the current photocell installed by the manufacturer) but I’ll have another look to see if there’s space for it somewhere.

Brandon92
Posts: 773
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Oil boiler

Thu Nov 22, 2018 10:04 pm

Your are writing that your boiler had some electric in them. So, do you know it has a communication connector somewhere. Or can you buy something from the manufacture to control the boiler from a distance. If so, that part could also have a indication if the boiler is active. And this may be a easier way of getting information from your boiler.

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Thu Nov 22, 2018 10:12 pm

Unfortunately, the boiler is too old to have any form of automation incorporated into it.

Brandon92
Posts: 773
Joined: Wed Jul 25, 2018 9:29 pm
Location: Netherlands

Re: Oil boiler

Thu Nov 22, 2018 10:33 pm

Okay.
Maybe a other option could be mounting a proper temperature probe on the output (tube)** of the boiler. Or a other save place where it is closer to the "hot place". But be very careful with placing part inside the boiler*.You don't want to block some important airflow. Otherwise your boiler could produce the deadly CO.

*I would not recommend that. That you place something inside the boiler. Also if the boiler damage something, and the issurent company sees that you heve modified it. I think you have a big problem then.

Edit
**you could also sense the temperature of the input water. To see it the output is still hotter than the input.

User avatar
buja
Posts: 498
Joined: Wed Dec 31, 2014 8:21 am
Location: Netherlands

Re: Oil boiler

Thu Nov 22, 2018 11:08 pm

I think a Pi is perfect for this kind of thing, but there is some engineering to do.

As mentioned above, tampering with 240 VAC brings serious safety issues, but even 24 VDC and 12 VDC are not without issues. And a Pi can take only 3.3 Volt DC for input, anything higher than that will fry the SOC.
But there are current and voltage sensors that are perfectly safe to use (example: https://www.tinytronics.nl/shop/nl/sens ... 3-000-100a).

Your first question was about measuring oil consumption. Measuring the weight of the tank would be the best way to do this, but probably not very practical. Some kind of level sensor is what you need here. Mounting a sensor inside the tank is probably not a good idea (you don't want any electrics inside an oil tank), but there might be sensors that can measure the liquid level from the outside. Maybe a flow sensor on the oil line from the tank to the boiler is a good solution.

So you need to look for sensors that can be used in your particular situation, and you probably need to do some Analog-Digital conversions as well. Everything you need is out there, but you need do some searching and some engineering to make it work.

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Thu Nov 22, 2018 11:17 pm

buja wrote:
Thu Nov 22, 2018 11:08 pm
I think a Pi is perfect for this kind of thing, but there is some engineering to do.

As mentioned above, tampering with 240 VAC brings serious safety issues, but even 24 VDC and 12 VDC are not without issues. And a Pi can take only 3.3 Volt DC for input, anything higher than that will fry the SOC.
But there are current and voltage sensors that are perfectly safe to use (example: https://www.tinytronics.nl/shop/nl/sens ... 3-000-100a).

Your first question was about measuring oil consumption. Measuring the weight of the tank would be the best way to do this, but probably not very practical. Some kind of level sensor is what you need here. Mounting a sensor inside the tank is probably not a good idea (you don't want any electrics inside an oil tank), but there might be sensors that can measure the liquid level from the outside. Maybe a flow sensor on the oil line from the tank to the boiler is a good solution.

So you need to look for sensors that can be used in your particular situation, and you probably need to do some Analog-Digital conversions as well. Everything you need is out there, but you need do some searching and some engineering to make it work.
Thanks for this and I’d actually previously looked at getting a flow meter but the price for one was horrendous.

Sogoing back to the clamp idea you’ve mentioned above, would this plug into the PI and what would be the steps after this?

User avatar
buja
Posts: 498
Joined: Wed Dec 31, 2014 8:21 am
Location: Netherlands

Re: Oil boiler

Fri Nov 23, 2018 6:52 am

Did I mention clamp? I am not sure what you mean here.
Looking at it some more I agree with other posters that making modifications to the boiler installation has some safety issues.
Which makes the idea of some light sensor looking at the flame inspection window a very attractive one.
Prices for hobby flow sensors for water are somewhere in the 5-10 euro range, but for oil/petrol/diesel they are quite a bit higher.

For the oil level sensor I looked at level sensors for fuel tanks for yachts. They work with a float, similar to fuel tanks for cars. Probably not precise enough for measuring the actual consumption, but at least you have an indication of the oil level.

For the Analog-Digital conversion there are, again, many options. I have an Explorer HAT Pro lying next to my keyboard. This device has 4 analog inputs (0-5 Volt) and 4 digital inputs and comes with a Python library, could be just the thing you need.

Lusk
Posts: 7
Joined: Wed Nov 21, 2018 9:16 pm

Re: Oil boiler

Sun Nov 25, 2018 8:07 pm

buja wrote:
Fri Nov 23, 2018 6:52 am
Did I mention clamp? I am not sure what you mean here
The item you posted is a clamp and used for measuring current.

Return to “Beginners”