Lost heating oil

Memyself_2

Hi - I have a tricky problem. I'm convinced I've been short-delivered of heating oil but may find it difficult to prove. I don't use a wireless gauge as these only register in 250 litre units in my 2500 litre tank. I use a Watchman dip stick which has 48 marks, so each mark represents 50 litres. I dipped the tank before an order for 1000 litres, then again after delivery. The level should therefore have gone up by 20 marks, but it went up by less than 16. This makes the delivery 800 litres and not 1000 ordered and paid for. Did I make a mistake in the pre-delivery reading ? No - because I have been dipping twice a month for the last 9 months as part of my oil conservation strategy which I put in place last summer. All previous readings are consistent with the one taken before delivery. I have treble-checked all my figures and readings. I have complained to the supplier but am simply informed by them that 1000 was delivered.
I have read on this forum of others who have complained of being short delivered, but they used their meter as a guide. This is too coarse at 250 litres per change of level. My dip rod may not be perfect but 200 litres is 4 notches = 4 inches in depth in my tank.
Question 1: If my rod method is accurate, and I can't see why it is not, then if I have been scammed, how many others have been as well ?
Question 2: Has anyone else made a similar discovery ?
Question 3: If there is a scam taking place, how big is it and how widespread.
I don't like the feeling of being ripped off like this.
Anyone have any comments ?

bobhawke

There are a few more things to consider. First is that the level of kerosene can change depending on temperature, not as drastically as lpg but it happens.

Drivers can't fiddle with the meter that measures how much fuel they pump out and they are regularly checked and serviced.
What they can do is fiddle with the tickets / ticket numbers etc and use that to steal from people and short them on deliveries. If it is the driver screwing you over then the company shouldn't have a problem proving it by going over his delivery tickets and tachographs. If the company is in on it then you are going to have a lot more trouble proving it.

Memyself_2

With temperature the same over the short period between taking the 'before' and 'after' readings it wouldn't account for a 4" depth variation over an area of some 25 square feet.

I'm interested in the possibilities of drivers altering metering systems. I've read of them altering their tachograph equipment to avoid breaking driving period regulations.

All I know is that I've been screwed by somebody for close on £100 and I'm not happy about it. It means that I will never trust another delivery without having the driver measure by dip before and after in my presence. What little faith I had left in human nature has been diminished yet further.

oysterman

Memyself wrote: »

With temperature the same over the short period between taking the 'before' and 'after' readings it wouldn't account for a 4" depth variation over an area of some 25 square feet.

I'm interested in the possibilities of drivers altering metering systems. I've read of them altering their tachograph equipment to avoid breaking driving period regulations.

All I know is that I've been screwed by somebody for close on £100 and I'm not happy about it. It means that I will never trust another delivery without having the driver measure by dip before and after in my presence. What little faith I had left in human nature has been diminished yet further.

99.99% of drivers would have no idea how to alter the metering system & if they could, they are sealed by trading standards or the meter manufacturers ie Alpeco. We have our meters calibrated once a year & any adjustments are done then.
I take it your dip has been calibrated by an official body, because otherwise you have'nt got a leg to stand on. I have been to customers who have said exactly the same as you, i just tell them to phone the office. It would'nt matter to me about seeing the dip before & after, because it mean's nothing.

alanfp

oysterman wrote: »

It would'nt matter to me about seeing the dip before & after, because it mean's nothing.

OK so it might mean nothing to YOU, but that's irrelevant. It sounds like a very reliable measurement technique to me, that could be easily verified. How do you think flow meters are calibrated?? they use tanks of a known volume - a known cross-sectional area and a height difference - just like the marks on a dip stick.


Did you (memyself) get the delivery ticket with printed meter readings? I agree with oysterman that this should be quite reliable - as reliable as when you fill up with 30 litres of petrol at a petrol station.

w50nky

What sort of tank do you have? Is the tank the same dimensions all the way top to bottom as in my old steel tank, or is it plastic with stiffening sections or bowed in the middle. This may not give a linear reading on your dipstick. My "new plastic" tank has stiffening sections in the middle part of the tank so a dipstick would not be accurate on my tank.

Just a thought.

Memyself_2

My tank is a Titan 2500 - Bunded - so tank in a tank. Yes, the outer walls at top are ribbed, and yes I accept that there will be variations in capacity at different levels. The walls are very rigid, very upright. I thought all this through before I decided to ask for opinions as it would be unwise/unfair to report a perceived shortage of say 50 or even 100 litres.
Yes, the ticket was machine printed so indicating the volume automatically recorded by the delivery. I understand that this equipment has a tolerance of just half of 1%. I found myself looking at an estimated 20%
It has been suggested that temperature variation between 'before' and 'after' could account for some difference. I agree, although in my case there was minimal temperature difference.
I just cannot find a rational explanation for the perceived volume loss of my estimated calculation of the area of the inner tank at that location - between 20 and 24 square feet multiplied by the dip measured difference of 4 inches. I make that between 6.7 and 8 cu ft. One cu ft = 28.32 litres so by volume I come to between 190 and 226 litres. My dip rod calculated variance is in fact 225 litres but I opted for the lower figure of 200 as a more reasonable estimate on which to base my case.
I hope I have explained my standpoint such that whichever way I look at it, I find it too hard to put down to linear anomalies. Why would Watchman, who made the rod, bother to mark it in 48 equal graduations if they are so meaningless. Why not just 3/4, 1/2, and 1/4 full? Incidentally on occasions I have compared a dip reading with a gauge reading that had just newly registered - and they tallied.
The only way I can ultimately prove to myself if I am right is by removing either 800 or 1000 litres, which of course I am unable to.
Do I make sense or do I sound just like a moaner looking to complain?
I actually wish to be proved wrong or be given sufficient room for doubt. I'd then be quite happy to withdraw my case. Any volunteers?

oysterman

OK so it might mean nothing to YOU, but that's irrelevant. It sounds like a very reliable measurement technique to me, that could be easily verified. How do you think flow meters are calibrated?? they use tanks of a known volume - a known cross-sectional area and a height difference - just like the marks on a dip stick.

A customer showing me a dipstick reading to me before & after is irrelevant, unless the customer can verify to the company how accurate it is, they will not do anything about it.
To get it calibrated would be very expensive i would imagine. The trouble with these plastic bunded tanks is there shape as has been said already, i would have no idea how to work out the contents of it, but i would imagine the shape of the tank is where the answer lies.

Memyself_2

Thanks Oysterman and others who responded. I have to admit, as I said at the outset, that making any sense out of this I knew would be difficult. I'm pleased that no others have had a similar problem (or at least no others have said so), and concede that there must be one or more hidden causes (like tank shape variations) to make my dip-stick system unreliable for this sort of purpose. A pity, as it has been useful as an indicator of my usage under varying weather/temperature conditions. It so happens that 200 litres is the (perceived) amount I was using per month in the coldest period of winter, or 50 litres a week. I shall still continue to monitor my use. When this time next year I purchase another 1000 litres - won't it be interesting? But don't watch this space!

Cardew

Memyself wrote: »

Thanks Oysterman and others who responded. I have to admit, as I said at the outset, that making any sense out of this I knew would be difficult. I'm pleased that no others have had a similar problem (or at least no others have said so), and concede that there must be one or more hidden causes (like tank shape variations) to make my dip-stick system unreliable for this sort of purpose. A pity, as it has been useful as an indicator of my usage under varying weather/temperature conditions. It so happens that 200 litres is the (perceived) amount I was using per month in the coldest period of winter, or 50 litres a week. I shall still continue to monitor my use. When this time next year I purchase another 1000 litres - won't it be interesting? But don't watch this space!

My gut feeling is that you are correct in being 'short changed' as 200+ litres discrepancy is difficult to explain away unless your tank is weirdly shaped.

I am also cynical enough to believe that if there is any sort of scam possible, even involving people in the depot, then there will be some people willing to take advantage.

However your chance of ever proving it, unless you laid a trap with authorities involved, are zero now. Even then if another driver(or even the same one now they are aware of your concerns) came then it could a full delivery.

On a slightly different tack, I know(well am completely convinced) that a petrol station was giving me short measure. To cut a long story short, I carried out some investigations that confirmed by suspicions.

I reported it to Trading Standards who at least took it seriously. However they apparently checked and gave the station a clean bill of health. However the official hinted to me that the pump recording could be 'fixed' despite them being 'foolproof'. However when I pushed him for more details he clammed up and refused to discuss the matter.

w50nky

Good luck with your tank problem, hope you get to the bottom of it, (no pun intended).
On a final note my next door neighbour had a problem with their Bunded tank leaking from around the outlet union nut. This was due to oil in the secondary bund tank which must have either leaked from the inner tank or perhaps when filled the oil may have been pumped into the wrong tank (if this is possible). Could this have happend to yours?

I will have to have a look to check when I next call for a beer.

Good luck.