Avoid Leaks By Being Careful When Changing Your Oil Furnace Filter

Oil furnaces are usually reliable and operate without much regular intervention other than refilling the oil storage tank. That helps make oil furnaces a popular heating option for individuals who don't have access to natural gas, but they do require a bit more maintenance than gas furnaces. One area that is unique to oil furnaces is the need to change the oil filter at least once per year. However, done incorrectly, a filter change can lead to frustrating oil leaks. Below is more information about furnace oil filters and how you can prevent leaks at this critical location:

Furnace oil filters—an introduction

Oil filters for home heating furnaces are similar to the kind found in automobile engines. Heating oil is forced into the filter body, through a special paper filter element, and out of the filter again. The filter paper is pleated to increase the amount of surface area available to catch debris caught in the heating oil. After a while, these filters become clogged with particles and are unable to filter efficiently; that is when a replacement becomes necessary.

The parts of of an oil filter canister

The oil filter itself rests inside of an oil filter canister like a caterpillar in a cocoon; The canister contains several parts:

  • Housing – this consists of a sheet metal cap and body that fit together to form the canister.

  • Oil inlet and outlet fittings – these are attachments for the incoming and outgoing oil lines.

  • Canister bolt and washer – this long bolt runs from the top of the filter cap all the way down into the bottom of the canister; a felt washer rests between the bolt and the inside of the cap.

  • O-ring seals – one o-ring seals the junction between the cap and body and the other serves to seal the canister bolt at the top of the cap.

  • Air bleed screw – this small screw is adjustable for the purpose of bleeding air from the oil line.

  • Air bleed washer – this is a small felt washer that prevents the air bleed screw from leaking

If the process of changing your oil filter isn't carefully performed, chances are good that a leak will be introduced into the system. All of the above components can be a source of leaks if good practices aren't followed. Next are some things to keep in mind when changing oil filters:

Oil filter changing hints

  • Keep everything clean - while it may seem unnecessary to be concerned about the cleanliness of the oil filter, its canister and the surrounding area, it actually is important. Cleanliness results in a couple of benefits:

  1. Wiping down the filter canister, its fittings and the areas in close proximity helps increase the visibility of a future leak. Dirty parts only camouflage oil leaks, and they be frustrating to find should one develop.
  2. Wiping down the areas where washers, screws and bolts rest against the housing will provide for better sealing o-rings and washers. Tiny pieces of debris can prevent proper sealing, but a simple wipe can remove this problem.

  • Replace o-rings and washers regularly – o-rings and felt washers are not designed to last more than the life cycle of one or two filters. That's why it's best to purchase replacement o-rings and washers whenever you know an oil change is due.

  • Be careful while tightening and loosening fittings – fittings are a source of leaks where the oil goes into and leaves the filter canister. They are weakened by careless, rough handling, and their junctions with the oil lines can spring leaks quickly.

  • Double-check the bolt and screw for tightness – it is not unusual for even professionals to forget to close the bolt and bleeder screw after replacing an oil filter. However, don't force the bolt and screw and risk stripping threads or damaging the housing. Also, keep in mind that missing, torn or worn-out o-rings and washers will not permit a fastener to tighten completely, and you may need to replace them before proceeding.

For more information, contact a local heater repair expert in your area. 

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