How to Remove & Clean Your Oil Furnace Pump Screen

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Heating oil often contains more than just petroleum; it can contain water, dirt, insects, and other foreign matter that can clog or damage oil pumps. That's why the screen on your furnace oil pump is so important. As it catches potentially-destructive materials, it will gradually fill-up with the waste and will require intervention on occasion. Below is how to remove and clean your oil furnace's oil screen:

Tools and materials needed

Step-by-step procedure

1. Disconnect the electrical power and shut-off oil valve—Before working on the oil pump, it is critical to disconnect electrical power as well as turn-off the valve leading from the oil tank. This will prevent an accidental activation of the furnace which could cause burns or electrical shock. Never rely on the thermostat alone to protect you from injury.

2. Remove the oil pump screen cover—After ensuring that the electrical and oil supplies to the furnace are shut-down, locate the oil pump screen cover. It typically will be in a prominent location, and most manufacturers attach a label bearing information about the pump such as rated pump RPM (revolutions per minute), heating oil volume per hour, date of manufacture and other relevant data.

The oil pump screen cover will be attached to the pump housing with a minimum of four screws or bolts, sometimes more, so use an appropriate tool to remove the fasteners. Be prepared for oil to seep out of the pump housing when you remove the cover, so place a shop towel or other absorbent material beneath the housing.

Once you remove the cover, take a look inside of it. If you see a lot of water, sludge, dirt, rust or other debris, it may indicate your heating oil tank is contaminated. If that is the case, then contact a qualified furnace repair professional for assistance in getting the oil tank cleaned-out or replaced.

3. Remove the oil screen—After the pump screen cover is removed, the oil screen is the first thing visible. It will be inserted into the pump housing, but it can be easily removed by pulling it from the housing. Remove the screen and set it aside for cleaning.

4. Inspect the inside of the screen housing and clean it as needed—With the oil screen out of the way, you can see the inside of the housing. Inspect it for debris and deposits, and clean it with a damp shop towel soaked in mineral spirits. If necessary, use an old toothbrush or other similar plastic-bristled brush to scrub the interior of the screen housing to loosen debris. After scrubbing it out thoroughly, give the interior a final wipedown with a shop towel.

5. Clean the oil pump screen cover and oil screen—Fill a five-gallon bucket with hot tap water and add a tablespoon of grease-cutting dishwashing soap. Place the oil pump screen cover and screen inside the bucket and allow these components to soak for about half an hour.

After soaking the screen cover and screen, remove them from the soapy water and use a toothbrush to remove sludge and other contaminants that have accumulated. Rinse the components in hot water to remove soap and allow them to air dry. If the screen is thoroughly clogged and old, you can also replace it with a new part available from your local heating supply company.

6. Replace the screen and screen cover—After cleaning the pump screen cover and screen, push the screen back into the pump screen housing until it is firmly seated. Next, attach the pump screen cover to the housing with the fasteners you removed in step two. Be sure that the pump cover gasket is properly aligned and that you don't pinch or dislocate it during the reinstallation process.

7. Bleed the air from the pump—After the screen cover is securely attached, turn on the furnace electrical power and oil supply. Turn the oil pump air bleed valve, located in close proximity to the cover, in a counterclockwise direction and start the pump. Air inside the screen housing and pump will escape via the bleed valve; if the pump begins to shut down, quickly close the bleed valve to prevent air from flowing back into the pump.

You may repeat this cycle until oil begins to emerge from the bleed valve; at that time, you will have removed all the air from the pump. Click on this link to look at more info on how you or a professional can ensure the pump screen is good and clean.