Depending on the type of system, there can be one or two filters in the boiler oil supply line from the storage tank, both types offering a DIY project for an oil furnace filter replacement.
If there are two, the primary filter beside the tank will remove water as well as particles from the oil, the other filter being fitted to the piping inside the boiler room. There are a few items which need attention during an oil furnace filter replacement, namely, switching off the boiler controls and shutting off the filter isolating valves before beginning and then ensuring all of the air is out of the system when the filter replacement is complete.
DIY Steps to Oil Furnace Filter Replacement in an Oil Furnace System
Oil fired central heating is not as common now that we have natural gas; however, many homes are still heated using oil. The oil is normally stored in a fiberglass tank, from which the oil supply pipe runs. One or two filters can be fitted to the pipe to ensure a clean supply of oil to the boiler.
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Introduction to Oil Furnace Filter Replacement
Even though the boiler oil, has been well filtered and cleaned during its processing from crude oil, filters are still required, especially if the oil is being supplied from a steel storage tank.
The filters perform a very important function in an oil fired central heating system, minimizing the dirt and water that can enter into the boiler fuel system, which will eventually damage the pump and block the burner fuel nozzle causing the boiler to “lock-out“.
This is an article about filter replacement for an oil furnace. Here we will provide a safe and relatively easy method for an average DIY person to carry out. (Just as well; a boiler service does not usually include oil filter maintenance unless the boiler has been causing problems).
We will consider two types of filters, and begin with the method used to clean the glass bowl type of filter located at the tank outlet, before moving on to the disposable filter located in the boiler room.
Glass Bowl Filter Stripping and Cleaning (Done Yearly)
- Switch off the boiler controls; we don’t want the boiler oil pump to start up when we are working on the oil lines!
- Shut off the valves on each side of the filter.
- Holding a plastic container underneath the glass bowl, open the butterfly-shaped valve and let the oil drain away from the bowl into the container.
- Turn the glass bowl clockwise screwing it off from the top inlet/outlet cover.
- Remove the nylon filter element and give it a good cleaning in the container, using the oil saved from draining the bowl.
- Renew the gasket between the bowl and top cover and refit the filter and bowl. The bowl will be slippery, so wrap a dry cloth around it, turning the bowl anti-clockwise until it tightens against the top cover, and then shut the bowl drain valve.
- Open the isolating valve nearest the tank, and let the bowl filled with oil, checking to be sure that there are no leaks.
- Holding a container underneath the filter, open the air release cock on the top of the bowl cover, letting the oil run out until a good flow of oil exits without any bubbles, and then shut the air release cock.
- Open up the isolating valve between the filter and the house, and again check the filter and both valves for leaks.
- Switch the boiler controls back on and let the boiler run for a while to be sure it is operating correctly.
Replacement of Disposable Filter (Done Yearly)
- Switch off the boiler controls and shut off both filter isolating valves.
- Holding a container underneath the filter, unscrew the bowl from the cover, allowing the oil to drain into the container.
- Continue to unscrew the bowl until it comes away from the top cover, keeping it upright (it will still be full of oil). Tip out the old filter and oil into the container.
- Wipe the inside of the bowl well with a dry, dust-free cloth and fit the replacement oil filter.
- Renew the gasket ‘O’ ring seal between the bowl and top cover and refit the bowl.
- Open the valve furthest away from the boiler and check for leaks.
- Hold the container below the filter, and open the air release screw on the top cover, allowing the air bubbles and oil to flow out.
- Once all the air has been expelled, open the valve nearest the boiler and recheck both valves and filter for leaks
- Switch the boiler back on and let it run for a while, making sure it is operating correctly.
- Dispose of the oil and old filter elements at the local recycling site.
Summary
There are two types of oil filters which can be used in an oil-fired central heating system. The filter elements in both types are easily cleaned or replaced by the average DIY person.
Oil filters play a vital role in the operation of the central heating system. Ensure that any particles in the oil are removed before they damage the oil pump or burner. One filter separates out any water in the oil as well as acting as an oil filter. The other type, an in-line filter, has a disposable filter element.
There are a few things to look out for during the oil furnace filter replacement, such as ensuring the boiler is switched off and filter isolation valves are shut before starting the job. Also, it is imperative that the air is removed from the system before restarting the boiler.
Used filters, gaskets, and oil should be disposed of at the local recycling site.
Sketches of Oil Filters and Layout of Oil Supply Piping to Boiler
Reference Webs
- Locating your Furnace Filter – Auchinachie
- What you need to know about furnace filters – National | Globalnews.ca
- How often should furnace filters be changed? – Newport News, VA
- What problems can a dirty furnace filter cause? – Rinaldis.com
- How much does it cost to have a furnace serviced? – ImproveNet
