Servicing your hot water boiler to save fuel and the environment will mean you'll need to set aside a few hours and learn the basics to what keeps a hot water boiler running smooth. Doing this yourself can save hundreds of dollars annually on a heating service company.

Oil fired Residential Heating BoilerCredit: DreamakerThere are several types of heating systems that run on oil. One contains a hot water boiler and this is the first type we'll discuss.

Conventional wet base hot water oil fired boilers use an injection style burner that mixes the proper amount of air with an oil spray and then ignites this mist within  a combustion chamber. This chamber is in the middle of a cast iron block that holds the heating water for the system.

Most boilers have three or four bolts that hold this burner to the front of the boiler. Some will have a door on two hinges on the front of the boiler. If you have the hinges then you'll be unbolting the nuts that hold the door shut. If you have no hinges then you'll be unbolting the burner from the boiler.

Sometimes the burner oil line will have to be removed at the mechanical connection and other times the oil line will be flexible enough to pull it away from the boiler. If you have a hinged door on your boiler then an electrical plug may have to be pulled apart to enable the door to open.

Weil Mclain boiler with hinged burner door.Credit: dreamakerThis burner assembly must be removed in either case to allow access to the burner nozzle inside of the boiler. This nozzle is usually a 5/8th inch socket to remove and the new nozzle should be the exact same firing rate and angle as the one you remove. This rating is stamped on the brass nozzle in all cases.

Unscrew the old nozzle and replace it with a new one every year. This nozzle costs only a few dollars and will save you hundreds on the first no heat call you have to make to your service man.

The burner assembly should be cleaned of any soot and you should inspect the porcelain insulators for any cracks. Also observe the ends of the electrodes that hang over and ignite the nozzle spray. Look for burnt tips, replace them if they look bad.

Follow the oil line from the boiler back to the oil storage tank and locate the oil filter. Next
 locate the shutoff valve on the oil tank and close the valve. next place a shallow pan under the filter housing and unscrew the cap screw that holds the assembly together. The bottom half of the oil filter will be loose and can be lowered to remove the old filter. Install a new filter cartridge and reassemble the housing.

Open the valve and your finished with this part of the job. Next we need to disassemble and inspect the flue piping. This is usually put together with sheet metal screws and can be taken apart easily with any household screw gun and a chuck to fit the screws in your system. The drill will help even more when your reassembling the sheet metal piping.

Once you have the flue apart at the easiest location to give you a good look inside, take a wet dry vac. and clean any soot or ash from the pipes. Now look on top of the boiler where the flue pipe was removed. You should see the pins between the sections of cast iron that make up the boiler.

boiler cleaning brushesCredit: dreamakerUsing a boiler brush, clean out all the spaces between the sections with an up and down motion. This should drop all of the built up soot and ash into the fire box. Once it's all down the bottom you can vacuum out the chamber with your wet dry vac.

Once all of the burnt debris has been removed and you have installed your new nozzle, the boiler and burner can be reassembled and the oil line must be bleed.

To bleed your oil burner you'll need a small container to catch some oil. There is a bleeder screw usually on the bottom left side of the burner.It's a small 3/8 inch fitting that looks like a grease fitting or a brake bleeder screw. This must be opened and then the container placed under it to catch the oil. Turn the boiler on and allow the oil pump to push out the air.

Continue this in twenty second increments, turning the boiler off and then back on slowly. This will keep the safety from thinking there is a problem and locking out the control. It may take several attempts to bleed out all the air. If you do pop the reset, just give it about 5 minutes and reset the red button then continue.  Once you have a good stream of oil coming out close the bleeder screw and place the boiler back into normal operating condition.

One of the commonest ways that people get ripped off every year on service calls is they pay to get the service work done and the company comes, they change the nozzle and the oil filter and then leave. Boilers need extensive cleaning to keep their flueways clear and operating to their maximum efficiency. Saving fuel and the environment takes a clean running boiler. Letting this service go can cost a substantial amount of money.

oil fired hot air furnace.Credit: dreamakerCleaning procedures for a hot air furnace that s fired by oil is the same for the burner and oil tank filter. The difference lies in the combustion area. Furnaces will have small openings to brush out the soot. Some will have a removable back to get inside and clean them out. Make sure to take apart the flue piping and inspect and clean the entire run.

Some furnaces require a special softer brush to prevent damage to the heat exchanger so make sure you have the maintenance instructions for your unit to prevent causing more harm then good.

Always make sure to run the system up to temp after servicing to check for any leaks or other issues and date the unit so you'll know when it was cleaned and serviced. good records will help you to keep from overlooking this important annual procedure that will help you learn how to service an oil fired hot water boiler to save fuel and the environment. 

How to Clean and Service an Oil Burner
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