How often should an interior fuel oil tank be cleaned out?

Some background info:

I've got an interior 275 gallon heating oil tank of indeterminate age (though probably not more than 25 years old). The heating system gets the standard annual maintenance from my oil supplier (cleaning, filter, screens), including the addition of a pint or so of "acetene (A) tank treatment & fuel conditioner" / sudge dispersant & etc. Though I can't pick out a manufacturing date on the boiler, the manufacturer's service literature is present and has 1976 dates. The burner tested at 83% efficiency last summer, down from 85% two years prior. The burner's transfer coil and control unit have been replaced within the past two years, and the flow control valve shows evidence of some slight leakage (and I decided to defer the $450 repair). We use about 950 gallons of oil annually (in eastern PA).

My oil supplier offers a "tank cleaning" at $250. Being flush with cash at that time, I had them do this in 2000. Basically, they drained all of the remaining oil and did whatever other magic they do as part of that work. On at least one occassion since that time (although we're on automatic delivery) we actually ran out of oil, and so the tank was presumedly thoroughly drained.

Here's my question:

Is there enough value associated with cleaning out the tank as to make it worth doing periodically? And at what interval? Is the "tank treatment" fluid likely to be sufficient to maintain the interior of the tank in reasonably good condition?

Thanks in advance for your observations and advice.

Oscar.

Reply to
oscar.hodgson
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I have never heard of a "tank cleaning service" -- it sounds like a revenue generating idea created by the heating oil company.

Any tank that is 25 years old, cleaned or not, may be questioned by your insurance company with a demand to replace it with a new tank. Insurance companies don't want a huge payout for environmental cleanup if it should leak.

Reply to
EXT

Underground tanks have a life of 15 to 30 years. Above ground tanks considerably more. You can do ultrasonic tests that reveal rusting of the tank. I've never heard of one being replaced because the insurance company requested it, but I guess it can happen. I know of may tanks that are 50 years plus and still working.

Reply to
Edwin Pawlowski

Here in Canada, it is common for Home Insurance companies to require tanks that are 25 years old or more to insist on them being replaced, because of this they actually caused a shortage in tank supplies as the replacements increased in number.

Reply to
EXT

I can understand that on tanks exposed to weather or ground moisture, but a basement tank? (Assuming a dry basement, of course.) As long as outside shows no signs of rust, I'd think a borescope inspection of interior every five years or so (I assume these things have a bunghole?) would be more than adequate. I know the pickup tube isn't on the bottom, but as long as no rust flakes are visible in the drained sludge, what are the odds of major interior rustout with no outside evidence?

(Having said that, any interior tank should of course have a spill berm around it, or be sitting in one of those giant kitty litter pans.)

aem sends...

Reply to
aemeijers

My parents sold their 50 year old house 4 years ago. Original tank and had never been cleaned.

Reply to
Art

I'm with you there Art - I'm pretty sure that I have oil tanks in my rental houses that are 75+ years old. When we have removed them, there is a fair amount of sludge in the bottom, but we have never had a serious issue due to dirt in a tank. These are all in basements, not buried.

JK

Reply to
Big_Jake

I only have my own case as an example. House is 28 years old. I've never done any maintenance to my tank, on legs in my basment. When I started reading this list, someone brought it up, so I looked at the bottom of the tank and afaict it loooked the same as 24 years ago.

Because I'm screwed up, and not always on auto delivery, I've run out of oil at least 4 times (once which I was on auto iirc) and I guess since the fuel line has no filter, every time I've run out, I've had to prime the pump again, and I think every or almost every time, I've had to replace the nozzle (which has a hole so small I can't barely see the opening and can't see the hole) But most people replace the nozzle every year anyhow, isn't that right. I found a place that will sell me nozzles, for times I run out of oil.

Reply to
mm

There can (and often is) moisture in a fuel oil tank. There are two outcomes. One is the tank rusts. The other is microbes that grow in the area between the oil and water and feast on the oil since oil is slightly hygroscopic causing "goo" which blocks equipment.

All (new/replacement) interior tanks have been double wall for some time.

Reply to
George

I know a few friends whose insurer required tanks to be replaced only because of age. It also lessens further risk because all new interior tanks are double wall.

Reply to
George

I'd change insurers. They are welcome to come and inspect my tank, but I'll be damned if I'm going to replace a perfectly good tank just because it hit a certain age.

Our insurance company at work (as well as state law) requires we inspect our air tanks every two years. It takes about 5 minutes to do an ultrasound on one. Much cheaper that scrapping good material.

Reply to
Edwin Pawlowski

And all the water in the tank will collect at the bottom to cause rust there where it will do the most damage. Normally however a sudden failure is pretty rare and pinhole leaks occur well before any significant leak.

Perhaps in your particular area, however you can readily purchase and install a new 275 or 330 gal single wall steel tank in most areas.

Reply to
Pete C.

But after one wall fails, eventually the other wall will too. So in the long run, how is this better than single wall?

Reply to
mm

Because it seems the concept of having a tank forever will disappear.

Reply to
George

My buddy has a fuel oil company. He said the typical failure is that the rusted tank blows while being filled.

Might be old inventory or something and of course there is a lot you can do when no one is looking. According to my buddy there is some requirement for new/replacement to be doublewall.

Reply to
George

George,

I don't doubt that there is some moisture in heating oil. Even if there isn't moisture will still get into the tank. In cars there are products known as Dry Gas that will solubilize and remove this water in the gas tank. Doesn't the heating industry have something like this?

Dave M.

Reply to
David Martel

Yes, and it is also available in jet fuel (kerosene) for the same reason.

Reply to
George

That is indeed the typical catastrophic failure, caused by not inspecting and noticing the pinhole leaks that were there for at least a year or more prior.

Again, probably a local requirement. MA perhaps?

Reply to
Pete C.

Additionally, there are water absorbent "socks" that you can put at the bottom of the tank (on a string for removal) that will absorb water and not the fuel oil. You replace them periodically and some are wringable and reusable.

Reply to
Pete C.

It's better because there is an alarm / indicator of some sort monitoring the space between the tank walls. Inner wall fails, alarm goes off and the tank is drained and replaced before the outer wall can fail.

Reply to
Pete C.

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