Oil Supply Line Clean/Flush Out

BrooklynMike

I have a 275 gallon oil tank in the basement with an oil line from the tank bottom to the oil burner. The copper oil line runs along the edge of basement floor and wall to the oil burner about 15' . There is a 1A25 filter and Oil Safety Valve (OSV)mounted to the valve at the tank bottom. Since there is an OSV, there is no oil flow when the line is disconnected at the oil burner. I have a push pull hand pump that I connect to the oil line to pull oil from the tank and push it into a container. I am hoping that this sucks out whatever sludge or dirt is in the line to cause a blockage in the future. My question is: Should I do this before or after installing a new filter element and is there any benefit in doing this with no filter element installed to get a faster oil flow to carry away whatever sludge or dirt is in the line. Or will this just suck more sludge out of the tank . Thanks

HydronicMike

You should always push the crap back into the tank, not thru the OSV.
The filter should be catching all the crap before it gets to the OSV, that's its job. Otherwise something could lodge into the OSV preventing it from working properly. If you have that much crap in the tank, you may need to get it cleaned, or if old, replaced.
People may recommend additives, but in reality they aren't going to work that well, nor take an old tank with a lot of sludge and clean it out. In fact on an old tank, the sludge is coating the bottom of the tank and keeping it from leaking. Ask anyone who has replaced a tank, scraped out the sludge on the old tank only to uncover dozens of pinholes.
If you have an actual clog, remove filter element., remove OSV. Use your push/pull pump and pump the oil line from burner into a bucket (right before OSV). Use push/pull pump and pump the oil line from where the inlet of the OSV would be, thru the filter (no element) back into the tank. Make sure OSV is clear. Hook everything back up (new filter element) Bleed oil line.
It helps to have flare fittings on both sides of the OSV. Many people put a nipple on the outlet of the filter and screw the OSV onto that. With a flare set up, I can use my small flex hose with 2 male flare ends on it, disconnect the OSV, and jump around it to push oil from burner back to the tank.

EdTheHeaterMan

@HydronicMike

I would never recommend putting sludge back into a tank.  The rest of your recommendations are great.   If you believe there is a lot of sludge in the tank bottom, you can place a deep tray under the filter holder with the cartridge removed and allow the oil flow to push any sludge out of the tank into the pan.  Dispose of that sludge properly.  After the oil flows clear, reassemble the oil filter with a new filter cartridge and connect your push pull pump to the oil line near the burner.  Pump the clean filtered oil thru the OSV and the oil line that may be partially blocked with sludge.  Keep pumping until you get clear oil.  

Now put the fuel lines back on the pump and operate the pump with the high pressure line disconnected from the nozzle.  Operate the pump until the oil runs clear, then put the high pressure line back on the nozzle assembly.  Your fuel lines are now clear and ready for a season of trouble free operation.

EBEBRATT-Ed

Some recommend install an empty filter canister between the tank and the oil filter to use as a sludge pot to collect sludge.

HydronicMike

@EdTheHeaterMan letting oil flow until it’s 'sludge free' doesn’t clear the oil line and only removes the crud in suspension. The rest of the junk in the tank is still there, and pumping it back pushes all the crap back away from the tank outlet.

You’d have to pump it back if the outlet were clogged, right?

@ebebratt-ed

Sludge pot is useless. What happens when it fills up? If it were like an oil/water separator that would be different, and better

HVACNUT

You're not going to disrupt much pulling the same direction as the oil flow. Disconnect after the filter and push it backwards into a suitable container. If the strainer has sludge, maybe think about adding a spin on filter after the 1A. At only 15 ft, you could replace the oil line.

EBEBRATT-Ed

@HydronicMike sludge pot is not my idea, George Lanthier "Fire Dragon" came up with that one and he is the recognized expert. I never tried it so I don't know just throwing it out there.