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Improving Oil tank gauge accuracy.....ideas???

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Leonard
Leonard Member Posts: 903
edited January 2018 in THE MAIN WALL
I don't have automatic oil delivery. I call for prices before delivery, and sometimes tank gets VERY low before I remember to check it . Need to know if I can make it over weekend, without lugging 6 gal jugs of heavy diesel from gas station, bad back. Other times need to know if I can take on 150 gal min ( price break point) . Single family home. 275 gal tank , 44 inch vertical.

Got a feeling tank float gauge is pretty non-linear and not very accurate, want better. Pain to open tank and measure with stick. Can you recommend any reasonable priced good accuracy electronic pressure sensors to determine remaining oil level. I realize I'll have to convert height to gallons with a tank calibration curve. Any bettter ideas??

I though about running tank empty then filling tank and calibrating float gauge as it empties ( ~ every 10 or 20 gal), knowing burner hours and nossel GPH, but that's a summer job. Last night I added hour meters to oil burner and circulator. Needed to know worst case daily usage (was exceptionally cold yesterday, -10 deg to +10 deg span) .

I thought about clear hose to see oil level, but that's a leakage and fire risk. I don't want to do that even with valves that someone might get left open.

Oil fired forced hot water to cast iron baseboards (1 foot high) , tankless domestic coil in water jacket.

Len
Mechanical Engineer



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Comments

  • unclejohn
    unclejohn Member Posts: 1,833
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    Not too costly just to get a new gauge.
  • Alan Welch
    Alan Welch Member Posts: 270
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    Scully golden gallon gauge.
  • vibert_c
    vibert_c Member Posts: 69
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    @Leonard are you capable pouring boiling water over the top edge of the tank and feeling with the back of your fingers where the temperature changes drastically along the hot water track?

    Mark it with chalk, measure it, and if your interested I have a spreadsheet to show the gallons similar to a dip stick reading in the old days. I did it for both sizes of the standard oval tanks.

    You engineers don't have not much imagination do you!

    vibert_c
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,250
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    Or, you can just pop one of the 2" plugs out and dip it with a measured stick - old school CAVEMAN style. Works for me! :p. Mad Dog
    GordyDZoro
  • Robert_25
    Robert_25 Member Posts: 538
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    Might be easier to just put an hour meter on the burner and keep track of how much you use. If you don't want to do that, the Scully gauge mentioned above is probably the best you can do.

    With that said, how much do you really save over a season by playing the will-call switch around game? Seems like running out once and having to drive to the nearest fuel station would wipe out your savings.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    edited January 2018
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    You could also get an oil meter if its a 1 pipe setup. We have i stalled many of those in public housing. Similar to your burner hour meter but more of a direct measurement.

    I have the site tube, connected at the top back into the tank! Put a "dead man valve" at the bottom, spring return normally closed ball valve. That way you have to force it open to take a gander and it automatically closes. Still not really legal though.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    You shouldn't let it get that low anyway. When it gets to a 1/4, order more, or go on auto-delivery...
    With the recent cold snap, it's hard for delivery companies to keep up. Add in in climate weather and you could run out.
    They make electronic gauges if you have to know exactly how much fuel is in there, but do you really need to know?
    iButton (not an Apple product) makes all kinds of interesting stuff that might give your brain a workout. They work on pressure. But it will require programming and skills I'm not interested in acquiring, for something not necessary.
    Except for the newer fuel gauges on cars, the only way you truly knew where empty was...was to run out.

    There was an error rendering this rich post.

    DZoro
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,840
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    Pipe a gage glass like a steam boiler off the end of the tank. You can buy long gage glass probably special order. Then you could see and measure the oil level.

    Make darn sure you close the valve at all times when your not reading the oil level.

    may not be legal to do

    To me it's more trouble than it's worth. Go on automatic delivery
  • Gordy
    Gordy Member Posts: 9,546
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    Not going automatic puts you at the bottom of the list in busy times for sure.
    New England SteamWorksDZoro
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,521
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    You are over thinking things my friend. That wheel has already been invented. It's called automatic delivery. As others have said, you may think yourself clever checking spot pricing, but when the mercury touches zero, the only cleaver ones are those on automatic. Without a relationship you'll be hunting for scraps. I realize it never sounds traumatic in September, but it becomes very much so with cold like this. Oil companies watch the weather, anticipate, and plan for their best customers. They are never going to find (let alone hire) the staff required to keep pace with cold like this. Not economical.

    I like to say that you have to eat, and you have to heat, everything after that is optional.

    So get on automatic already and stop worrying. That's worth a whole lot right there.
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
    STEVEusaPA
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    To me, if you want to take the gamble of the cheapest oil, get enough tank capacity to ride out most or all of the winter. You can have up to (3) 330 gallon tanks here in Maine. That's a real world 900 gallon capacity. If you have the space and the money to spend, get those. Then you can have them filled in the summer/spring/fall when it's cheaper. Also can use the one large delivery as a negotiating tool for one time best price. All 3 tanks get T'd together so you just need one gauge, you do need two vents and two fills though as only (2) tanks can share a common fill/vent.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • BobC
    BobC Member Posts: 5,481
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    i went without a working tank gauge for 15 years, I bought my oil from a local dealer on a will call basis but to get his best price I needed to order 125 gallons minimum.

    I wired in a elapsed time indicator so I could track the hours that gun fired. i always ordered oil when I figured I had used 150 gallons and in 15 years I was never off by more than 5 gallons. The oil dealer said I was his most consistent customer.

    i always intended to replace that gauge but I never got around to it.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    ratio
  • HVACNUT
    HVACNUT Member Posts: 5,890
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    The Beckett Rocket is a wireless transmitter/receiver. Just plug the receiver in the house (mine is in the kitchen). Dip switches on the back get set for your specific requirements.
    Other manufacturers offer WiFi with an app.
    bob eck
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,840
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    @Solid_Fuel_Man , MA used to be (4) 330s. But since they dumped their code a couple of years ago they adopted NFPA 31??. I am not sure what they allow now
  • Leonard
    Leonard Member Posts: 903
    edited January 2018
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    Curent Float gauge has slightly different readings each time tank is filled up, odd

    I have 2 goals I want from a new gauge
    1) know when tank is down by 150 gal , so I can order oil at the price break --- (this one's easy)
    2) know very accurately (to ~1 gallon) how much oil is left if tank gets REAL low (like 30 gal). So can decide of I have to get diesel from gas station to make it till oil truck comes, (weekend issue)
    I burned 8.7 gal/day when it was VERY cold last few days.
    ------------------------------------------------------
    Scully and rocket gauges-- sound good , but unlikely to give me the 1 gallon accuracy I want when almost empty

    Got a feeling ultrasonic will spread out too much to read oil level when oil is less than ~1/2 the width of tank (very little oil left)

    Overall my gut feel is a pressure gauge or laser depth gauge will give me the 1 gallon accuracy I'm looking for. I just don't know if these are commonly available in the heating industry

    Reason for this renewed interest in accurate gauge was it's been COLD here and oil co said they were slammed and couldn't delivery for 10 days. So I needed to know exactly what I had in the tank.

    Think your idea of going back on auto delivery is a good one. Problem was in past they let me run out, now they claim to use degree day method instead of once a month fillup.

    Hour meter and nossle GPH will work, I put meter on it couple days ago. Just little concerned my calculated zero point will drift off over time , due to nossle GPH error accumulating over time.

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    More tank = better price!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Leonard
    Leonard Member Posts: 903
    edited January 2018
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    Though about a 2nd tank, but would have to move a lot of stuff to get it in cellar and installed. Besides not a full solution, I burn 1200-1500 gal/yr
  • Robert_25
    Robert_25 Member Posts: 538
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    Might be time for a new fuel supplier. The good ones have it down to a science and won't let you run out.
  • vibert_c
    vibert_c Member Posts: 69
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    @Leonard you surely are caught between a rock and a hard place by being one stubborn cuss.
    Based on your tank being 44 inches high and 24 inches wide shaped elliptical, you may take on 150.3 US gallons when the dip stick reads 15 inches depth.

    However at your current daily rate of use of 8.7 US gallons per day you only have a reserve of 9.5 days at that point. With the necessity of ten days notice for a delivery, I sure hope you are living alone in this dwelling.

    A winter spent above the arctic circle would surely change your perspective on purchasing fuel oil. A delivery in Nain Labrador by ship is once a year under normal ice conditions.

    Go downstairs with your electric kettle and pour eight ounces of boiling water slowly over the crown of the tank so that it runs down the near side. The stream of water will heat the steel in the tank only above the level of oil inside. You may determine this temperature gradient threshold with your finger within a forty second time frame. The Eskimos taught me this technique. Surely you can manage it!

    vibert_c
  • Gordy
    Gordy Member Posts: 9,546
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    ^ I was taught similar tactic on how to find a solid silver plug on a silver plated meat tray cover of old. Usually if it was engraved with initials the area of the engraving was solid silver. However to be sure, fog over with your breath the silver plug stands out perfectly.
  • Leonard
    Leonard Member Posts: 903
    edited January 2018
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    I figure I'll calibrate mark the existing tank gauge to show when I can take on 150 gal, via hour meter and nossel GPH method.

    Was really hoping someone in oil business sold a pressure or laser depth gauge for accurate readings to 1 gal , when almost empty ( 30 gal). Don't really want to open and stick the tank, wife doesn't like diesel smell.

    Tried hot water method and feeling with hand , didn't work great on a propane tank in past. Guessing not very accurate when down to last 10 gal. Besides tank is in cellar, lot of stuff nearby that wants to stay dry. I'ld stick the tank first.

    In past I always could get oil delivery next day, or Monday. Just was surprised by ~ 10 (and 6) day waits this cold snap. Luckily found a guy I used to buy from for next day delivery, he came at ~ 9:30 pm next night.
  • Jamie Hall
    Jamie Hall Member Posts: 23,655
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    When one burns 30 plus gallons per day in this cold weather, "will call" just isn't an option... years ago we had a 3,000 gallon underground tank. State made us take it out -- it wasn't leaking. Sure like to have that back again...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    I never seen so much energy spent on a convoluted solution to a self made, and basically, non existent problem...oh yeah, mechanical engineer...sheesh
    I know people may think I'm being rude, but I feel sorry for an oil company, if after all this monkeying around with a bung on the oil tank, a delivery is made and a spill occurs. You could have a bung open and a wrong delivery could cause a spill.
    Properly close all bungs in the tank, and if your too hard headed to go on auto delivery, just call when you're down to 3/8, as read on any of the basic industry standard tank gauges that have been around for 60 years, and move on.
    Reminds me of the many threads on the forums of people obsessed with wifi t'stats-needing to constantly know and manipulate the temperature in their house.

    There was an error rendering this rich post.

    CTOilHeat
  • Leonard
    Leonard Member Posts: 903
    edited January 2018
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    Yes I'll give you that it's likely being too accurate, but I've found a need for it while auto delivery let me run low ,then out. Just wanted to know if an accurate gauge is commonly available or if I have to design it myself.

    8.7 gal /day is worst case ,in very cold average 0 deg for the day , maybe 5 /day at 32 deg average. I figured want to know when ~ 30 gal so will know if I can last the weekend.

    I always sealed plug with telfon tape and monkey wrench tight since I knew it wouldn't gurgle to warn filling guy it was full. In fact that part is a PITA as I carefully hand clean threads of teflon so stands wouldn't plug valves, then retape it

    Of course cost is an issue , so I've thought about adding reserve tank, old ~ 23 gal propane tank (100 pounder) set up so will fill off main tank. Figured on removing propane valve , mounting tank inverted, and reducing tee fitting & internal pipe, so don't need to WELD a vent port on PROPANE tank.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    edited January 2018
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    If you ever have to weld on a decommissioned L.P. tank, just fill it with water first. Weld on it while full, that is the cheap way. Or you can fill with Nitrogen or C02, and keep things dry.

    We wood burners use 500-1000 gallon L.P. tanks for pressurized heat storage for the absolute Cadillac system.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Leonard
    Leonard Member Posts: 903
    edited January 2018
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    I wasn't eager to weld on a fuel tank. I have heard the water and inert gas methods. I have oxy-actylene and co2 tanks , but I'm cheap I'ld likely use water topped off with co2 if welded on it.

    Interestingly I've also heard people putting exhaust of a running lawn mower engine into tank for ~ 5 minutes to flush out all the oxygen. I had a lawn mower with it's crankcase vented into carb intake. It had bad rings and had so much blow by (exhaust) that engine would bearly run. That is until I pulled crankcase vent off carb intake and let it vent directly to atmosphere. Then it ran perfect.

    I wouldn't use a car exhaust, they inject air into exhaust for the catalytic converter. I'ld worry about it still having oxygen at tailpipe.
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
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    Got hour meter on the burner now. Tank and gauge are 60 years old, pic of similar type gauge is in this web link.

    Do you think this type gauge will slip/stick? I'ld be happy with ~1/32 inch accuracy ( ~2-4gal) on gauge display near 1/4 full. To calibrate gauge I've been taking daily measurements of tank gauge with machinist's gauge to 1/32 inch accuracy. Trying to calibrate gauge with oil re-fill gallons and hour meter, to find 150 gal empty point.

    From hour meter and nozzle I'm burning ~6.5gal/day (30 deg outside ) and 8.9 when averaged 0 deg outside. ( very cold for southern NH)

    My guage looks very similar to one in picture of this link
    http://www.city-data.com/forum/members/karen_in_nh_2012-1295435-albums-house-related-pic99111-oil-tank-guage-2013-02-28.jpg


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    You need help, or meds, or both. I'm a little concerned about your obsession to solve a problem that doesn't exist.

    There was an error rendering this rich post.

    Robert_25Solid_Fuel_Manvibert_c
  • rick in Alaska
    rick in Alaska Member Posts: 1,458
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    Look into the Beckett rocket. Used to be made by scully. It is a distance measuring device that just screws in to the top of tank and measures distance to fuel . Not sure of its accuracy though. You could also look into the Petrometer that is used in commercial tanks.
    Rick
  • Gordy
    Gordy Member Posts: 9,546
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    I'm sorry, but if you can't just look in the tank, and know you need a delivery soon. No amount of gauge accuracy can help. As a matter of fact it will be worse, because then you will push it to the edge even more.
    CTOilHeat
  • Robert_25
    Robert_25 Member Posts: 538
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    You need help, or meds, or both. I'm a little concerned about your obsession to solve a problem that doesn't exist.

    My thoughts exactly. Get a competent fuel company to handle automatic delivery.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,840
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    @Leonard , not to be disrespectful but don't you have better more important things to do than worry about fuel deliveries and tank gages??

    Any competent oil company can put you on auto delivery and your worries will be over. You can move on to other tasks.

    You can work on your income taxes
  • BobC
    BobC Member Posts: 5,481
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    Please watch your language, Tax is a four letter word.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    GordySolid_Fuel_Man
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
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    I'm semi-retired mechanical engineer. Just because it's interesting, since last fill up 2 weeks ago I've been recording burner hours and measuring tank gauge with machinist's ruler ( 1/32 inch divisions) each night at 10:30pm. Making a calibration graph for the gauge, also want to see how repeatable it is. Been dropping ~ 2/32 inch on gauge per day ~ 6 gal.

    I plotted up these two measurements in a speadsheet expecting to see a non-linear curve due to linkage angles of the gauge links. Tank is ~2/3 full now, but surprisingly graph is a straight line so far. Will have to see if that continues down to below 1/4 full. But I don't expect it to, linkage kinematics.

    Nice thing is now with the hour meter I can pretty accurately predict when tank will be near empty and can schedule a fill up a week in advance so I can take gauge measurements down to almost empty without serious risk of running out of fuel.

    I'll stick the tank when it gets low as a cross check. But I remember when I vacuum cleaned the tank seeing float hanging some 3- 6 inches above tank bottom. So when gauge stops dropping that will be a red flag.
  • Gordy
    Gordy Member Posts: 9,546
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    The reason the graph is linear is because the outdoor temps must be pretty much linear for the period.
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
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    no, I should have been more clear in saying what I was plotting.
    I'm Plotting drop in gauge VS gallons burned.
    Trying to make a calibration curve for the gauge

    -------------------------------------------------------
    Not sure why but one potential problem I noticed was when I had tank FILLLED over many times, gauge reads:

    -- different levels of full each time (non-repeatablity).
    -- Also, all displayed levels were less than gauge full mark (zero error) this error is easy to compensate for

    Fairly sure I heard the tank whistle gurgle just before they stopped filling each time ,so tank SHOULD have been filled to same level each time.
    Hoping non-repeatability is not gauge friction/sticking.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    I would swear we're getting punked here. No one can be that consumed with this. It just goes to show you what happens when an engineer gets involved-talk about making a mountain out of a molehill.

    The tank will never get filled to the exact same level. Each truck pumps at a different speed (pressure), plus the temperature changes (the viscosity of the oil). Faster speed, more pressure, more foam & turbulence will cause the fuel to stop the whistle sooner.
    If I fill a tank at high speed until the whistle stops, wait 30 seconds, I can dribble in more fuel slowly, and hear the whistle.

    By the way, I hope one day you don't forget to properly seal the open bung where you keep sticking the tank, and the oil company has a spill.

    There was an error rendering this rich post.

    Leonard
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
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    Engineers think differently, we like to analyze things that catch our attention. Besides this is more of a curiosity.

    Foaming ....... good !! That explains that puzzle of why gauge reported different levels even though filled to whistle stop each time. That means my gauge might not be sticking. I watched it as tank was filled. Sloshing of oil seem to "bobble" gauge reading around as if it did not stick or have friction, so sounds good. Now that I think about it gasoline foams too.

    Thanks, but no chance of forgetting to seal bung, first threat I thought of after I opened it was truck's 3000 gal on my cellar floor. Don't like the smell of diesel.
    CLamb
  • D107
    D107 Member Posts: 1,860
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    HO here. Family house has a 275 gal tank with 11-year old gauge. Oil co uses 'K' factor/degree days to figure out deliveries. They never let it get down below 1/3 tank. Auto delivery is the main thing many oil companies do really well--it's in their interest, not only to get paid sooner than later, but also prevent possible sludge issues if they let it get down too low. Once or twice the gauge got slightly stuck--meaning it read 1/8 tank too high or too low. So whenever I read it I give it a light rap with my knuckles just to make sure. Peace of mind is worth a lot.
  • Leonard
    Leonard Member Posts: 903
    edited March 2018
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    tank gauge calibration curve ........and burner/circulator hours VS days plot


    Had 275 gal oil tank filled 38 days ago. Been recording oil burner hours and measuring tank gauge every night. Using burner nossel size 1.1 GPM calculated gallons burned. Has ~ 40 gallons left now.

    Plotted up chart of gallons burned VS tank gauge level, expected wild curve like car fuel gauges have. Was amazed how absolutely linear ( straight) plot was. See link at bottom. This 60 year old gauge is VERY good, it's a Scully swing arm gauge, looks like this new one on web http://www.city-data.com/forum/members/karen_in_nh_2012-1295435-albums-house-related-pic99111-oil-tank-guage-2013-02-28.jpg

    Measured tank bottom radius and its close enough to a circle (14 inch radius). Did the math and came up with an equation to convert height of oil to gallons remaining. Sticked the tank ~ 8.3 inches remaining and I'll add that to my chart data to make a chart that DIRECTLY converts gauge reading to remaining available gallons of oil.

    Over all I've been VERY happy with this project. It'll tell me when I can take 150 gallons for price break , plus gives me a VERY good handle on what I burn per day on mild and also extreamly cold days.( 3-9 gal/day). This gives me GREAT peace of mind, can see I can easily make it thru the weekend, going to run tank to ~ empty to finish tank calibration curve in ~6 days.
    ------------------------------------------
    Also since I recorded water circulator hours and piloted them up with burner hours I can see I likely have high standby losses. On a warm 50 deg day circulator ran ~ 1 hour and burner ~ 3 hrs. ( hot water of 2 showers only account for < 1/6 to 1/3 hour of that ).