an Oil-Tank Monitoring puzzle : Domestic Heating

[Michael GilliganParticipant @michaelgilligan61133]

[Michael GilliganParticipant @michaelgilligan61133]

When I woke, early yesterday morning, the house was rather chilly

… Radiators were stone-cold, and the boiler was obviously not running.

My new abode has oil-fired central heating with an outside boiler.

Opening the box revealed that the boiler had shut-down safely, because it had no fuel. … This was a surprise, because the Apollo ultrasonic monitor showed the tank to be approximately half full [or half empty if you’re that way inclined].

Details of the monitor are here: **LINK**

Apollo Ultrasonic Standard level monitor

So … I peered into the tank and decided that the boiler’s opinion was good : there was just enough oil to reflect my torch-light, but the tank is effectively empty.

Therefore, the mighty Apollo must be telling porkies !!

I unplugged it from the mains, and had a look at the DIP switches:

1, 2, 3 are ON

4, 5, 6, 7, 8 are OFF

This configuration is not listed on the setting chart in the instructions !!

… so what does it do ?

.

I don’t need help, I worked it out this morning

… but I thought some of you might enjoy the puzzle.

In the best ‘Agatha Christie’ tradition; all the clues are there in the document, along with a small shoal of ‘Red Herrings’

Have fun

MichaelG.

.

Direct link to the Instructions: 

https://dunravensystems.com/wp-content/uploads/2022/09/apollo-standard-oil-level-monitor-instructions.pdf

… only two pages, and the all-important chart is the top half of page_2

Edited By Michael Gilligan on 28/11/2022 09:56:47

[derek hall 1Participant @derekhall1]

Hi Michael,

I also have oil fired central heating. I used to have the Watchman" ultrasonic level measurement device. It looked very similar to yours.

However the device did not last more than about three years despite new batteries and repeated "pairing". Hopefully your is more reliable than mine was.

Looks like the sw 1 DIP is always ON, the rest of them seemed to be switched depending on the height of the tank. I wonder if it ever worked?

Currently I am using a low tech method, a piece of wood approximately calibrated with levels of 100 litres that I occasionally "dip" to check the level !

All the best

Derek

[John Doe 2Participant @johndoe2]

You have not told us the height of your tank, unless I missed it?

[egaParticipant @ega]

A purchaser of a property with oil-fired heating will normally expect to pay separately for the fuel remaining in the tank at completion. It sounds as though he or she would be well advised to dip rather than rely on high tech gadgets.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Doe 2 on 28/11/2022 10:22:52:

You have not told us the height of your tank, unless I missed it?

.

… Overall height of my tank is 1420, according to the leaflet … so depth might be around 1300

[ but you don’t really need that to solve my puzzle: it just provides a nice checksum at the end ]

MichaelG.

Edited By Michael Gilligan on 28/11/2022 10:47:09

[David Millar 3Participant @davidmillar3]

Is the solution somehow "baffling"?!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by David Millar 3 on 28/11/2022 10:45:23:

Is the solution somehow "baffling"?!

.

No, David … nice try though

It’s strictly down to deciphering that table.

The device appears to be working exactly as it should.

MichaelG.

[Brian WoodParticipant @brianwood45127]

Hello Michael,

As I see it, the combination 1,2,3 of dip switches applies to any depth of tank above and including 2450 mm and the gauge is not set to read your smaller size tank as the oil level will be 'apparently' below sensing height. Is that correct?

Retiring now for a hot coffee!

Best wishes Brian

[John Doe 2Participant @johndoe2]

I have read the setting instructions twice, and for your tank, the DIP switches 1,3,5 should be up, all others down.

The sequence 1,2….. is for tanks 1800mm height or larger, so your receiver was expecting a larger tank, and hence reported half full when it was actually nearly empty.

Or: The sequence 1,2,5 might have been set in error instead of 1,3,5, thereby making the receiver 'think' the tank was much bigger?

I cannot see how to work that out without knowing the height of your tank? Pray tell.

Edited By John Doe 2 on 28/11/2022 11:14:27

[Michael GilliganParticipant @michaelgilligan61133]

I agree with your analysis, John … but that wasn’t actually the question

What I asked was what setting just 1, 2, 3 ON would mean.

… because that’s how it was set.

MichaelG.

[John Doe 2Participant @johndoe2]

Ah, my apologies for misunderstanding your question. Well in that case, I don't know,. The sequence 1,2,3….. might refer to several larger tank sizes, but with one 'digit' missing or transposed. I cannot see the specific combination 1,2,3 referred to anywhere. Please put us out of our misery !

[BazyleParticipant @bazyle]

Switch 1 is just the warning sound enabled. That's why it is always on in the table.

123 is 2425mm depth with warning on.

Edited By Bazyle on 28/11/2022 12:13:26

[Ches Green UKParticipant @chesgreenuk]

so depth might be around 1300

1 = 500mm …eg depth of 500mm

7 = 50 … eg depth of 550

6+8 = 100…. eg depth of 600

So 650 mm is 1,6,7,8 ie 500 (1) + 50 (7) + 100 (6+8)

Therefore 1,2,3 is ….well, I haven't got round to adding it all up but I think that is the gist of it

Ches

 

 

 

Edited By Ches Green UK on 28/11/2022 12:22:22

Edited By Ches Green UK on 28/11/2022 12:22:51

[Taf_PembsParticipant @taf_pembs]

I've got a similar type remote gauge in mine..

Great until they fill it to the brim which is then touching the sender unit.

It tries it's best – bless it – to work out what's going on for about 12 hours or so then gives up and decides someone is nicking the oil so sounds the alarm in the house – usually about 3AM..

[Speedy Builder5Participant @speedybuilder5]

I didn't see if you told us the gauge reading. If the gauge read half full, I can understand why.

Dip setting

Ie 123 on and others all off.

If the dip switch had been put in upside down then the reverse would be trueIe

123 off and 45678 on

That is set for a tank size of 2900 depth and would indicate that your tank was half full. Very clever of the previous occupier if he sold you the fuel !

Edited By Speedy Builder5 on 28/11/2022 12:31:44

Edited By Speedy Builder5 on 28/11/2022 12:32:02

[Martin Johnson 1Participant @martinjohnson1]

The solution is:

Rip it out and get a heat pump.

Martin

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Johnson 1 on 28/11/2022 12:42:08:

The solution is:

Rip it out and get a heat pump.

Martin

.

No, Martin that isn’t the solution to the problem I set

… I just posed a simple question for people to exercise their grey cells upon, not their ‘green’ ones.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Speedy Builder5 on 28/11/2022 12:30:55:
.

I didn't see if you told us the gauge reading. If the gauge read half full, I can understand why.

[…]

.

1. Yes, I said the gauge was showing approximately half full
2. The switches are correctly orientated … and 123 isn’t on the list
3. I did not pay for the remaining fuel …
4. although the Seller did try it on just before completion

MichaelG.

[Bantam BillParticipant @bantambill]

2425

Edited By Bantam Bill on 28/11/2022 13:26:07

[Speedy Builder5Participant @speedybuilder5]

what I should have said was that if the switch was in upside down, then 87654 become 12345 and being upside down, OFF becomes ON

12345 indicates a tank of 2900

ie a tank twice as deep, so when your tank is empty, it would show half full on the gauge.

Bob

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bantam Bill on 28/11/2022 13:24:58:

2425

Edited By Bantam Bill on 28/11/2022 13:26:07

.

Nicely concise answer, Bantam Bill

I will show my working later, but I ended-up with 2420

MichaelG.

.

Edit: __ but first, a little digression: This is why I am getting double posts

.

.

The funny thing being that if I just ignore it and refresh the forum page, my post is there.

Edited By Michael Gilligan on 28/11/2022 14:09:13

[Michael GilliganParticipant @michaelgilligan61133]

O.K. here we go …

The first obvious problem is the presentation of the ‘switch setting chart’, which serves only to obfuscate a simple table … so I put all the values into a simple spreadsheet.

Then we note that Switch_1 serves a special purpose, and is not relevant to the height of the tank.

The pattern [clearly visible when the settings are neatly tabulated] is simple binary.

So … assign values to each of switches 2 to 8 and add them up for each row

Then notice that the sums contain those Red Herrings that I mentioned !!

Now leap to the obvious conclusion that the list of heights has been fudged for ‘cosmetic’ reasons … they don’t really increment by 50mm, but the whole hundreds work.

The value in my column L is always 500+(20x the value in colum K)

… As presented here I have left the 40mm increments blank

The bottom line is that 1100000 = 96

and 500+(20×96) = 2420

So my empty tank was showing approximately half full.

Having set the switches appropriately, it now reads empty and I am sitting here waiting for a delivery of oil.

Brrr !!

MichaelG.

.

[Bantam BillParticipant @bantambill]

I assumed it was binary and that a fudge factor had been included in the table, but I just took an educated guess at the value. It reminds me when I was trying to program my inverter and struggled to work it out but got it in the end.

Basically you have to create a 9 bit binary number and convert it to hexadecimal and enter that into the VFD. in my case I wanted to change the polarity of terminal S4 which is bit number 3 so:-

Bit number 8 7 6 5 4 3 2 1 0

Bit setting. 0 0 0 0 0 1 0 0 0

Convert 0 0 0 0 0 1 0 0 0 to hexadecimal (that’s easy use a converter from the interweb) = 8

Entered 8 on the VFD, result it works.

Suppose you wanted to change the polarity of all terminals, the binary number would look like this:- 1 1 1 1 1 1 1 1 1 The hexadecimal is 1FF which is what to enter in the VFD, also hexadecimals are usually prefixed with 0x so it should be written as 0x1FF.

 

Edited By Bantam Bill on 28/11/2022 16:03:04

Edited By Bantam Bill on 28/11/2022 16:13:01

[Dave Shield 1Participant @daveshield1]

It may not be the settings I once had a problem with a large tank and incorrect level readings, I could see the echo trace on my lap top and it showed two return echos. One was from the surface of the liquid The other which was the larger, was from the surface and then was being reflected from the top of the tank, back to the surface and then to the transducer. The top of the tank was a wonderfull reflector.

I have had the same type of problems with radio signals where a reflection from a hanger door been moved became stronger than the signal that I was using to check the kit I was working on.

Dave

[Author]

Posts