How to Change the Oil Filter Cartridge on an Oil BurnerHeating oil filter change:
Step by Step Oil Filter Change Procedure. This article series describes the installation, use, maintenance, and repair of oil filters used on oil-fired boilers, furnaces, and water heaters.
We discuss tracking down air and oil leaks at or near the oil filter canister and we describe proper oil filter location and problems to check for during oil filter cartridge changes.
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The oil filter cartridge should be changed during oil heating equipment annual cleaning, service, and tune-up.
You should not have to change oil filter cartridges more often. If the cartridge clogs and leads to service calls or heat loss between annual service calls then we suspect the oil tank is contaminated with water or sludge - problems that need to be corrected at the oil tank.
Illustration: the General 1A-25B heating oil filter canister, used on many domestic oil burners. This canister or "container" receives the General 1A-30 oil filter cartridge or an equivalent.
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The procedure for changing the oil filter cartridge is simple, but if it's performed improperly you could be left with no heat.
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Once you have installed the new oil filter cartridge inside the canister you will need to bleed air out of the canister and filter before restoring the system to service.
If your heating oil tank is at a level higher than that of the filter itself this is an easy task as oil may flow from the tank through the filter without even having to run the oil burner.
But most heating service techs simply turn up the heat to cause the oil burner to turn on, bypassing the cad cell relay if necessary to keep the burner running even before actual flame ignition.
Watch out: do not try this burner-on method if you don't have the necessary training: pouring a dose of un-burned oil into the combustion chamber is dangerous and risks a puffback.
With your catch-basin below the oil filter canister, simply loosen or remove the air bleeder screw located on the canister top just before the canister outlet fitting (red arrow in our photo at left, courtesy of reader E.S.).
Then open the oil supply valve to permit oil to flow from the oil tank into the canister. You may hear or feel air escaping at the air bleeder opening.
Once you see a clear flow of heating oil at the bleeder opening you can replace the screw that closes that port.
Watch out: don't forget to include the fiber washer that seals the screw to the canister head or you may have oil or air leaks at the canister.
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After any service procedure that disturbs oil line, filter, or burner oil piping fittings we recommend checking for evidence of oil leaks again after the system has been in use for a day or so, because slow leaks and small leaks in the oil piping system may not show up immediately.
Clean the floor beneath and around the heating oil filter and oil piping. Check back in a day or two for fresh heating oil spots on the floor (below left).
If you leave a clean paper towel below the oil filter and connectors it can make spotting an oil drip easier.
Fix any oil leaks immediately. An air leak into the oil piping system leads to improper oil burner operation, risking a dangerous puff-back, or loss of heat in the building.
Our reader asked:
The furnace oil filter changing instructions are for canister and not the spin-on cartridge pictured.
Are there separate instructions for removing and replacing a spin-on fuel filter cartridge (Gar-ber, Granby, etc)? 10/30/2014 Anonymous
Thanks Anon for pointing out the need for this clarification. For a spin-on type oil filter cartridge the basic steps are the same: shut off the equipment, shut off the oil supply, place a pan to catch drips, remove and replace the filter. The central difference is that there is no center bolt to remove to drop the filter (as is the case with General Filters).
The mounting hardware for this filter is (as with other brands) specific to the filter brand, size, type. Gar-Ber filters,for example, include a die-cast metal head to which the oil lines are connected and to the under-side of which the Gar-Ber spin on heating oil filter screws on and off. The Gar-Ber filter head includes a port for a vacuum gauge and it also includes an air bleeder screw that serves the same function as we describe in the article above.
Gar-Ber spin-on / off oil filters are distributed by General Filters - generalfilters.com
Granby spin-on / off oil filters (Granby EX200-999) are distributed by Granby Industries - granbyindustries.com and also provide mounting hardware that connects to heating oil lines and that also includes an air bleeder plug. Granby also sells a traditional center-bolt oil filter as well. Granby notes that their 10 micron spin-on oil filter works with all spin-on filter heads of the same type and fit the CGF-10, Kerr K10, Purolator Per-103 and Nozzle Guard NG1500-M oil filter mounts.
Granby's instructions include this helpful note that gives some heating oil line vacuum reference points
"SERVICE: Replace the filter element at the beginning of each heating season, or when running vacuum exceeds 6’’ Hg on one-pipe systems or 15’’Hg on two-pipe systems."
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Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
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What should the pressure gauge located after the oil filter read when everything is running correctly?
My gauge is at 6 or 7 should the filter be replace? Ty Joe d On 2019-11-17 by deutgrass86@gmail.com
by (mod) - 4" or less for your system
Deut
On a single oil line single stage oil fuel unit heating system you shouldn't see a vacuum reading over 4" so your gauge is telling you to replace the filter if that's your system set-up.
Generally if there is a vacuum gauge between the oil filter and the fuel unit (oil pump) for a single stage fuel unit on a two-line oil system will show 3-10 inches of vacuum when the unit is running. If the vacuum level gets much above that then the oil filter probably needs replacing, or there's a blockage or clog in the oil line between tank and oil burner fuel unit (pump).The service tech uses vacuum measurement to see if there are air leaks in the oil line or a bad fuel unit or similar problems.
A gauge on the high pressure line (out of the oil pump or fuel unit and in to the oil burner nozzle assembly) will read 100 psi or higher depending on how the fuel unit has been adjusted.
Watch out: pressure gauges in any location on a heating oil line or high pressure line between pump and burner should not be left permanently in place unless there are fittings to shut off oil pressure in to the gauge - to isolate it from the piping; my concern is that a burst gauge could spew oil all over and start a building fire or a leak at a gauge on the suction side of the pump may leak air into the system causing unsafe burner operation.
PLEASE read the details at OIL LINE VACUUM & PRESSURE TESTS where we include HEATING OIL LINE VACUUM TEST READING STANDARDS - you'll see that the acceptable oil line vaccum reading between the oil filter and the oil burner's fuel pump depends on the type of system installed.
Then don't hesitate to ask further questions. Daniel F.
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How do you know which size oil filter cartridge to use? Mine is the canister type with the felt insert but I've seen the cartridges in sizes 1A25B and 1A-30. There doesn't seem to be a size identified on the canister. On 2021-03-24 by Gene
@Gene,

You may have been confused by people mixing names for the oil filter canister - the metal container that holds the actual heating oil filter and the actual oil filter cartridge that is inserted into the canister and through which the heating oil is filtered.
In your question " I've seen the cartridges in sizes 1A25B and 1A-30. " actually the 1A25B is the name for the oil filter canister (container) manufactured by General, ,and the 1A-30 is the oil filter itself that is inserted into that canister.
Above: The General 1A-25A oil filter canister and its standard filter cartridge, the 1A-30. This is the most-common residential oil burner filter size, though equivalents are available from other manufacturers.
For residential oil burners most use an oil filter canister (the can that holds the filter) such as the General Filter Model 1A-25A.
That filter uses cartridge refills in size 1A-30.
There are also substitute oil filters that will fit in that canister like the F15-48 that are perfectly compatible
Also compatible is the A-315 filter. What's different is the material but the size and operation of all 3 fit into the 1A-25A canister.
Some residential oil burners and some commercial burners use a larger capacity oil filter canister such as the General Model 2A-700B.
This larger canister uses as actual filter cartridge refills the 2A-710BG, or the 2A-710, 101, or RF2 oil filter cartridges.
I'll add illustrations of these oil filter canisters and filter cartridges to clarify their use.
Thanks for asking.
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Below: the F15-48 oil filter cartridge from Westwood, and the rather different-looking
and next below,a same size Fulflo F10-209 oil filter cartridge, both of which fit and work in the General 1A-25A oil filter canister shown above.
Below: the larger General 2A-700B oil filter canister,
and the General 2A-710 oil filter cartridge that fits into this larger canister.
Above: the Parker Carborundum Fulflo process liquid filter model B3A-1/4" BD (Bottom drain), and below,
the General Aire from General Filters, Model 2A-17A similar to the General l 2A-700B above.
The 2A-17A oil filter can be used with No. 2, 4, 5, an No. 6 fuiel oil. It is also used for othe roil filtering applications.
Below: the Westood heating F65 oil filter canister, also using a cast-iron top and the company's Pure-Oil filter element - filter cartridge Nos. F30-24, F35-12, F35-24.
See this
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This is on so tight that I can't get it off. Do they make these kinds of filters
any more.
How can I get it off? On 2018-12-1 by Denise
Solution by (mod) -
Denise
Almost all of these oil filter canisters are disassembled by unscrewing the center release bolt you see in the filter canister top - the silver bolt pointed to by the red line at the canister top shown in my photo using a General 2A-700B as an example.
That bolt actually screws into a threaded receiver that's in the bottom of the black canister cartridge.
Once that bolt is removed, if the canister doesn't simply drop straight down, pry gently between the canister top and the canister base using a flat bladed screwdriver.
Watch out: to avoid unnecessary oil spills, work with a bucket or catch pan under the oil filter when removing it.
For the much less common oil filter canister that actually screws diretly into a lid, by holding the upper body of the oil filter with a suitable wrench and using an oil filter canister wrench on the bottom you should be able to unscrew the filter from the present installation. If not you could replace the entire assembly with a new oil filter assembly such as that made by General and shown here.
Or show me a photo of your oil filter canister and I can advise you further. - Daniel F.
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Awesome info- thanks so much! How often should I replace the cartridge in my filter? Is this like a once-a-year kind of thing? Thanks in advance. On 2018-04-09 by Kevin
by (mod) - once a year at the annual service of your oil burner
Kevin
I replace the filter at annual oil burner service. If you find that the filter is clogging and having to be replaced more-often than that there's a problem to be found and fixed at the oil tank - at the very least by increasing the filter capacity so as to make it to annual service.
Thank you for your valuable instructions and also for your forward thinking warnings. Cheers, On 2016-08-17 by David
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