I'm not real familiar with deposits in heating oil tanks but I know that diesel tanks in trucks and boats will develop a black algae that can eventually take over the entire tank unless you add the correct chemicals to the tank to prevent it. Those chemicals (a biocide to prevent the algae growth) are not in the diesel fuel you buy and must be added separately or the tanks will eventually become contaminated with algae

It's more of a problem in warmer climates than in cold ones, but once the algae gets a foothold, it can take over the tank. My Dad in Seattle had an extra 60 gallon stainless tank in the back of his RV puller and the algae got so bad that the tank wouldn't hold 30 gallons of diesel when it was 'empty' - Yup . . . . it had over 30 gallons of algae growing in it

Many boaters can tell you similar stories. The algae in the tanks plugs up the fuel filters and the engine stops. The solution is always cleaning the tanks

Not sure if this applies to home heating oil tanks or not, but if your underground oil tank has a few inches of black goo in the bottom and you have a problem with plugging up nozzles, I would almost bet that algae is the problem

Let us know what they find when they clean the tank. A tank cleaning on a boat or a truck involves sucking up the goo from the bottom of the tank, running it through a series of filters and returning the cleaned fuel back to the tank. They don't actually 'scrub' the tank - They just recycle the fuel through filters until all the goo is gone

Hope this helps,

Don

Anything is possible, but I doubt you have alot of sludge in the tank. Get a furring strip of wood and stick it all the way to the bottom of the tank and pull it up. You will get a good idea of the amount of sludge in the tank by the black area at the bottom of the strip. You might see a few inches at most.

Your system has at least two filters; one between the tank and the burner and the other inside the oil pump at the burner. Both should be replaced each year.

If the oil truck fills your tank too fast and stirs up the sludge and then you use your burner heavily, you may block up the first filter, but not the second.

If your nozzle is dirty, I would suspect an improper flame, improper spray pattern, sometimes caused by the tech putting his finger over the sprayhead when installing, improper air supply or other things that should be checked and addressed during the annual cleaning. Maybe even a blocked heat exchanger.

If the sludge in the tank is minimal, I would look at the quality of service work that was done during the annual service.

Most nozzles are dirty because the filter wasn't changed, the filter didn't do its job, the tech didn't replace the pump screen, the oil wasn't treated, nozzle after-drip (on older systems) or there's a two line oil system constantly circulating (cold) oil through the filter & pump strainer.

With the smaller nozzles we're running these days, I install a dual filtration setup with vacuum gauge, and single line oil supply on almost all new installations. We try to replace dual line systems whenever possible, and/or use a Tigerloop on some jobs to eliminate cold oil, and so much constant circulation/filtration of oil on two line systems.

Micro-Kleen Dual Filtration link below.

http://www.sidharvey.com/public/new_products.htm

Many of the typical General & FulFlo filters I see don't do a good job of filtering oil since they don't have much filtration area, they let smaller particles pass by, and once they're loaded they let more pass by. The most popular filter in the area is a General 1A-25A with 41 square inches of filtration area and a 50 micron filter element. Not too impressive compared to a GarBer spin-on filter with 500 square inches of filtration area, and 10 micron filtration. When a spin-on filter loads, the flow will stop. When a standard filter loads, particles will still pass by and get into the lines, pump/strainer, fittings, high pressure line, nozzle etc.

I treat most problem jobs by flushing the line(s) upgrading to dual filtration (Standard Primary/Spin-On Secondary) adding Fuel Right oil treatment, and trying to eliminate dual line systems (when possible).

I dump salvaged fuel into the tanks at my vacation home all the time. The pump strainer is spotless, and I'm on my third year with the same nozzle.

The difference in knowledge, skills and quality of service between techs in this business is incredible. The person that installs, cleans, tunes and services your oil fired heating equipment makes all the difference in the world.

Mark, has any genuine testing been done on the tank additives as to their effectiveness? I was supposed to try out some of the stuff last year, but it's still sitting on the shelf.

No time to read the trade journals, and wondering what is the industry's opinion of it?

Thanks for the info on the dual filtration Mark. I am guessing it works in the same way as a sediment filter for well water and makes alot of sense too.

How much does the unit cost? Is it easy to install? How often, on average, does the the filter need to be cleaned? Seems we have a Sid Harvey location about 10 minutes from us that he can use.

We will run this by our HVAC tech. He actually is a very good tech. Owns his own business for a zillion years, and is one of the few left in the business around where we live that we trust to do a complete furnace cleaning. We did venture to a cheap(er) HVAC guy one year and ended up paying for his lack of cleaning too.

Thanks for your help.

I have a basement tank about 60 yrs old, been told I need a new one by my fuel oil company (of course). I have sludge you see, they have been out a few times to repalce the filters, CO2 the lines and add tank additive. Better now but they said it will take aobu 2-3 more fills and additive to do the trick, if it5 works, othewisse I can try a float on top of the oil tank, or I need a new tank for roughly $3000. for a 160 gal tank.