Fuel station bowser calibration accuracy.

[Tuco]

This has been a concern of mine for some years.

I've had many instances where the amount of fuel displayed on the pump meter is way OVER what I got!
 
I do realise that if I'm topping up a tank and only going on the vehicle fuel gauge (which is NOT linear) then I'm lucky to estimate to the closest 10L the amount that is needed to fill the tank. I accept this.
 
However - when I'm filling an empty tank or container of known capacity, then I feel that the dispensing pump should give me correct measure.
 
A few examples ....

Filled a 20L 'Spectre" red jerrycan, which has a number of 'guide' calibrations moulded into the opaque plastic. I stopped at the top '20L' line and was amazed when I turned to see the fuel bowser displaying 27 Litres!!! The pump was definitely zeroed prior to starting by the console operator. When I questioned the accuracy and wanted to know when the pump was last checked for calibration - I simply got a blank stare from the junior console operator. I had to pay for 27 litres!
 
The 'Sub' tank in our Nissan Patrol is shown as 30L in the vehicle specs. Most times it 'clicks' of at 30.2 to 30.6 litres to fill the tank. There have been many instances where the bowser indicates figures up to 36 Litres!
 
Our dual fuel Ford F150 had 2 gas tanks. When empty, the normal amount to fill them was 78 to 79 litres before the nozzle auto clicked off. To my dismay one day it was showing 100 litres and still pumping!!
 
I can accept that there may be times where the pumps get out of calibrtion due to error or adjustment of some sort - but how come these innacuracies are always in the fuel suppliers favour? Simple logic and averages say that there should be some that short supply and some that over supply.
The questionable suppliers have been the two major retailers sites !! Have never had the occurence happen at an independant.
 
I'm in Queensland and tried to contact the Department of Weights and Measures - only to find it seems that they no longer exist and 'self certification' is now the go!
 
Something fishy here - the major supermarkets are supplying 4c fuel discount on purchases >$30 which on $1.50 fuel equates to a 2.66% discount - then they jack up the price by fiddling the calibration by up to (in my case) 7 litres extra in a 20 litre container =35% !!!
 
ANYONE ELSE WITH SIMILAR EXPERIENCE

[griz066]

Have you only just caught on this racket has been going on for years

[D4D]

Did you take into consideration expansion and contraction? That's why you should fill up in the cool of the morning...

[dazzler]

A guage is not accurate.  You would need to empty the tanks and fill up to know if you what you are suggesting is correct.

Weights and measures are normally pretty well on the mark.  Agree with D4D.

[Yimmy]

Petrol pumps always record the volume at ambient temp ie whatever is the outside temp.

Fuel will expand and contract based on temperature, in the fuel industry every measurement of fuel is normalised to 15 degrees.

D4d is correct that in the cool of the morning in theory you will get more fuel than in the heat of the day.

However it would not get anywhere near 20 percent or even 10 percent error.

I have been out of the industry too long now but I used to have the conversion factors and we were talking a correction factor of 0.9945 for example.

Anyway you will always get that volume of fuel at that temp. Eg if you fill up a 30l container at 10 degree you will get 30l, if the day heats up to 35 degrees then in theory your container will over flow as the fuel expands and hence you have more that 30l and vice versa.

Hope this has helped explain somewhat

Left the fuel industry 10 years ago and moved into the wine game, tastes a heap better 

Jim

[austastar]

Hi,
  If the volumetric coefficient of expansion of diesel is .00082/C°, and petrol is .00095/C°, I doubt you would be able to casually measure the difference between a cool and warm day unless you were buying fuel by the truck load.

I was right peeved when I put 21 Litres of fuel in a motorcycle tank that was rated as 20L, so I notified Weights and Measures.
They came out and checked all the pumps, and all were in specification, and all were still in date for test.

Perhaps I should have used  a measuring cylinder or some thing of a known exact volume before I cried wolf.

cheers

[Tuco]

Have you only just caught on this racket has been going on for years

Read line 1 of my post.

[sandman]

Did you take into consideration expansion and contraction? That's why you should fill up in the cool of the morning...

The temperature of the petrol stored in tanks underground remains relatively constant. A good friend used to manage a large fuel distributor hub and always said that this is only applicable to petrol stored in above ground tanks.

[Tuco]

Did you take into consideration expansion and contraction? That's why you should fill up in the cool of the morning...

You are correct re adjustment for temperature.

I used to work in an oil company terminal and was involved in stock keeping. Tank measurement, pipeline transfers, excise and import duties are all calculated (and paid) using complex tables which give the factors used to convert the volumes back to 15­°C (previously 60°F).

While I do agree that there is advantage in filling in the morning - the difference is nothing like the 7 Litre in 20 Litre overcharge that I once experienced.

[Tuco]

A guage is not accurate.  You would need to empty the tanks and fill up to know if you what you are suggesting is correct.

Weights and measures are normally pretty well on the mark.  Agree with D4D.

Please read 3rd and 4th paragraph of my post - exactly what I posted.

[Tuco]

I was right peeved when I put 21 Litres of fuel in a motorcycle tank that was rated as 20L, so I notified Weights and Measures.

Slightly off topic, but relevant to plastic fuel containers.
Back in the days I was racing Enduro bikes we would 'expand' Acerbis or Safari tanks by filling with boiling water and applying compressed air to the tank vent. The vent was then locked off and the water allowed to cool overnight. Amazing how much more capacity the tanks then had. Even if only 1 litre more was gained - it could relate to 20 to 30 K's more range - a long way to push a motorcycle!

[Yimmy]

Hey tuco,

My first job was stock reconciliation at pt stanvac refinery in Adelaide, hence my comment that my memory was getting hazy

Jim

[griz066]

Read line 1 of my post.

I was referring to the supermarket part of your post, I should have said that.

[dazzler]

Please read 3rd and 4th paragraph of my post - exactly what I posted.

I was referring to the vehicle.

If you had a 20l container and it takes 27lts then obviously something is amiss.  Why did you pay for 27 lts if your 20lt container only takes 20L?

Whats the story?

[briann532]

I was referring to the vehicle.

If you had a 20l container and it takes 27lts then obviously something is amiss.  Why did you pay for 27 lts if your 20lt container only takes 20L?
(And just for you antaganostic trollers - yes it was empty both times!!!!)

Whats the story?

Yeah............
I got 24 litres in my 20 litre container the other day.
When I questioned apu at the counter he told me the pumps were all calibrated.
I asked with what - cos they're $%^&# wrong.........

Refused to pay for 24 litres, offered to pay for the 20 happily as that's what I got.
He threatened to call the cops, so I told him to go for it. Not my fault the pumps gave the wrong reading.
He took my money for the 20 and grumbled that he was going to lose his job.
Not my problem.
Oddly enough, when I drove past the following morning there was a service van at the pumps.............
Next fill up, my 20 litre can only got 19.8 litres in it from the same pump.

Even stranger was that he still had his job..................

Now to the real pressing question.......

How am I going to sleep knowing that he doesn't like me anymore??? 

[Tuco]

Hey tuco,
My first job was stock reconciliation at pt stanvac refinery in Adelaide, hence my comment that my memory was getting hazy

Jim

My grey stuff is also a bit that way Jim - I was stock clerk at Total Australia (later taken over by Ampol) Whinstanes terminal (Brisbane) in the early 70's. Later took on similar position with Caltex at the Cairns terminal. Obviously deeply involved with pipeline transfers, inter company and ship to shore,  and payment of Excise and Import duties.

Several instances of being short changed at the fuel pump prompted me starting this thread.

[jetcrew]

Yeah............
I got 24 litres in my 20 litre container the other day.
When I questioned apu at the counter he told me the pumps were all calibrated.
I asked with what - cos they're $%^&# wrong.........

Refused to pay for 24 litres, offered to pay for the 20 happily as that's what I got.
He threatened to call the cops, so I told him to go for it. Not my fault the pumps gave the wrong reading.
He took my money for the 20 and grumbled that he was going to lose his job.
Not my problem.
Oddly enough, when I drove past the following morning there was a service van at the pumps.............
Next fill up, my 20 litre can only got 19.8 litres in it from the same pump.

Even stranger was that he still had his job..................

Now to the real pressing question.......

How am I going to sleep knowing that he doesn't like me anymore??? 

Thats the way to do it, when the cops arrive they could caution the servo for obtaining benifit by deception.

There is no way I would pay for more than I KNEW was in there, is bloody expensive enough as it is. imagine a beer with only 300ml instead of 375ml ....there would be a riot ..LOL

And don't stress Brain ...we still like you

Jet

[areyonga]

My LPG tanks allow my to just squeeze in 70 litres at nearly every servo but at many Caltex (Woolies) ones I usually get up to 74 litres, so much for the discounts they offer, they get them back as soon as you use fuel.  I avoid them now.

Trevor

[Hewy54]

I find these threads interesting, as so much is based on anecdotal stories. My wife has managed a service station for the last 15 years and been in the industry for 28 years.
1.  Employees of the companies do not tamper with the settings on the pumps
2.  The pumps are calibrated on a random basis by a govt controlled body. This calibration is also done as a result of any customer complaint.
3.  Out of all the pumps in Australia, and the number of fillups per day sometimes there will be inaccuracies. If you feel hard done by complain in the correct way and action will be taken.
4.  My wife has never had a complaint that a customer got too much fuel for their money, even when tests have shown that the pumps were reading low.
5.   The last customer that complained to my wife said the pump read 85 litres when his car only holds 70. He was only willing to pay for the 70, but when my wife offered to call the police to settle the dispute, paid for the 85 and left. Video footage showed him filling a jerry can before his car.

PS  A plea for those who work at petrol stations - they do not set the price so do not abuse the console operator when fuel goes up!!

[evolution]

I understand what you guys mean.

I filled up at a servo on my way to echuca from melbourne last weekend. I was on the empty line and was about to hit the reserve when a servo popped up so I filled up.
Now even saying that my tank (90L) was bone dry, and all my lines were dry, Maybe just MAYBE I might be able to squeeze say 93L in there.
When I finished filling up I had a look at the bowser and it said that I had put 108L in???!!!! WTF?

now even if im wrong and say the tank is actually 95L there is still a huge discrepancy, Considering it was a hi flow pump (yes I checked for spillage) and considering the trucks that go through there and the amount that they fill up. They must be having staff parties every week with the extra cash!

I will admit I got pretty angry when I saw how much was stated as going in my tank. my reserve was chockers full and I only have a 90L tank, plus there was still a little bit of fuel in there.
So I would be saying that there is around 15-23 litres that they tried to over charge me by.  I went into the servo and before anyone said anything I asked to see the manager.
I tried to calmly say what I thought was wrong and he looked at me like I was an idiot. I said to him that I wasn't paying for 108L on principle and said that as I explained before I would pay for up to 95. He threatened to call the police and like others before me knowing I was in the right I asked him to do it quickly so that I could be on my way sooner rather than later.
After another 10 min of arguing I got my phone out to call the police as I was sick of going around in circles he decided that paying for 95L would be more than ok and was rather apologetic??

I have since filled up at a Independent caltex down the road from my house the other day and the gauge was lower than when I filled up at the other servo and I only took 85L. IUnderstand that gauges can vary and all that but this really does highlight the general consensus.

whatever happened to HONESTY people? surely there are set parameters that petrol stations must have the pumps checked?

ok rant over.

Cheers
Evo

[bluejay]

Years ago There was a old saying in the fuel industry up is to us and down is to them... if you wind the gears on the pump up the retailer wins if you wind the gears on the pump  down the customer wins  which way do you think they are wound???

[evolution]

PS  A plea for those who work at petrol stations - they do not set the price so do not abuse the console operator when fuel goes up!!

I really couldn't agree more. Hence why I asked to speak to the manager.
I really don't think all service stations are out to rip people off, but surely if a question is asked the manager should at least investigate.
To be honest I don't think I have ever noticed getting more fuel than what I have paid for but it must have happened at some time.
As its allot easier to know just how much fuel can fit, if it goes over then you would notice, whereas if say you fill up on half a tank and it gives me a couple of extra litres I doubt I would even notice.
Like all mechanical things, items can break, get knocked, and need re setting. So an amount of common sense should be applied.

If the manager had been able to show me that I could have been wrong or what not I would have understood and accepted that. but it was too big a discrepancy to sweep under the carpet.
I think what I was most angry about was the managers attitude, I certainly wasn't rude to him. To be called a liar when its very easy to confirm what I was saying as truth then he shouldn't be in that position in my mind.

Cheers
Evo

[welchygq]

The error in the metering of the fuel should be minimal as the fuel is metered through a positive displacement meter.

This meter, at a base level, is a series of "cups" of a known volume that roate on a cam as the fuel passes.  The number of roatations is what is actually counted.

The advantage to this type of instrumentation is that it is very acurate and (in theory) any error is the volume changing in the "cups" should benifit the consumer and not the retailer - another motovation for the retailer to ensure that calibration is in fact acurate.

Now i am not say that anythign cant be played with or broken - but the setup used is very robust and (when used and maintained as inended) very acurate.  In the case of the 20L jerry can - have you done your own test to see how much it actually holds? - maybe measure the amount of fuel you can get out once full - buy a cheap large measuring cup?

And yes as everyone has said temperature does effect volume, however as someone else has said the temperature change of diesel stored underground does not have a dramatic effect on volume.

Welchy

[bunyip]

This is something that I have really never paid attention to.

Aside from the direct dollars lost by customers, this would also affect fuel economy figures (if the driver is recording these details) which in turn could lead to additional expenditure to try to "solve" a problem that does not exist.

So now I will drive LB crazy with recording volumes etc....

Bunyip

[Hairs]

Hey Buntip,
You can keep track of it all with, Fuelly