Rotary vane pumps are by far the most common truck-mounted vacuum pump type in the world, used in countless applications and industries across the globe. These pumps are known for their durability, ease of operation, and relatively simple installation, when compared to other types of truck mounted vacuum pumps and systems.

Rotary vane pumps are technically compressors (like all vacuum pumps) which create vacuum by compressing the air brought into the housing using an eccentrically placed rotor, with sliding vanes slotted into it. As the rotor spins at 1300+ RPM – the vanes are centrifugally pressed to the inner surface of the housing creating pockets between them. As these pockets pass the intake port of the housing, they pull in air and compress it into the smaller gap in the housing created by the eccentric placement of the rotor. This compression is where vacuum comes from.

Rotary vane pumps are very efficient at creating high levels of vacuum and pressure. However, they typically move less air compared to the increasingly popular blower-type vacuum pumps. Despite this, rotary vane pumps remain the preferred choice for most pumpers due to their simplicity, power, and durability, with the Fruitland rotary vane line being the toughest and most quality product in this category. 

How to Fix Common Rotary Vane Pumps Troubleshooting Problems

1. Lack of Vacuum in the Tank

Problem: The pump is spinning, but there is no vacuum in the tank, or the vacuum level in the tank is insufficient.

Possible Causes:

• Air Leaks: Inspect all hose connections, manways and sight glasses to make sure they’re sealed and aren’t leaking.
• Collapsed Hoses: Hoses on various parts of your vacuum system have an internal lining or diaphragm which can collapse shut under vacuum.
• Faulty or Stuck Backup Valve: Check the backup valve function by looking in through the diverter – you want to make sure it’s not stuck open or closed.
• Faulty, Broken or Stuck Primary or Secondary Shutoff: The float balls and cages in your shutoffs can become damaged or stuck.
• Worn Vanes: Over time, the vanes can wear down and lose their ability to create a proper seal against the housing.
• Dirty Filters: Clogged or dirty filters can restrict airflow.

Solutions:

• Check for Leaks: Tighten all hose connections and replace any damaged seals.
• Check Hose: Put the pump in pressure and see if pressure comes out of the hoses – if pressure comes out, but not vacuum- you have a collapsed hose.
• Check Primary and/or Secondary Shutoff: If the ball is stuck into the seat during operation, no vacuum will be pulled out of the tank. These float ball devices work similarly to the float balls in a shop vac – as the tank fills up it floats the ball close enough to the hose connection to suck the ball into it cutting off the airflow. 
• Replace Vanes: If the vanes are worn, replace them with new ones according to the manufacturer’s guidelines.
• Clean or Replace Filters: Regularly clean or replace filters to ensure proper airflow.
• Check Vacuum Tank Components: Inspect primary shutoffs (float balls), secondary shutoffs, hoses, connections, manways, sight glasses, and any other penetration into the tank that could reduce the quality of the vacuum.

2. Overheating

Problem: The pump is overheating during operation.

Possible Causes:

• Inadequate Lubrication: Rotary vane pumps require adequate lubrication to function properly.
• Faulty or Broken Oil Pump: Vacuum pump needs constant lubrication to run, if the oil pump is not functioning properly the pump will overheat very quickly.
• Blocked Airflow: Blocked intake or exhaust ports can cause the pump to overheat.
• Excessive Load: Operating the pump at a higher load than recommended can lead to overheating.

Solutions:

• Check Lubrication: Ensure that the pump is adequately lubricated according to the manufacturer’s recommendations.
• Check Oil Pump: Remove oil cover and check if the oil pump is pumping oil into the lines. Use recommended oil types.
• Clear Blockages: Inspect and clear any blockages in the intake and exhaust ports.
• Operate Within Limits: Make sure the pump is not subjected to loads beyond its designed capacity – like RPM, environmental conditions, dirty or clogged fan or fins.

3. Pump Not Turning

Problem: The pump fails to start or stops turning during operation.

Possible Causes:

• Mechanical Jamming: Broken vanes, debris, or other items present in the pump can stop the rotor. 
• Vane Sticking: Vanes can stick if not properly lubricated or if they are damaged.
• ‘Hydro-Lock’: If you pull fluid into the pump, it will most likely ‘hydro-lock’ by breaking a vane or an end cap as it tries to compress the fluid.

Solutions:

• Clear Jams: Check your shutoffs and filters daily to ensure there’s no risk of debris or fluid getting into the pump. Inspect internal components for wear and replace any worn parts as necessary.
• Lubricate Vanes: Ensure the vanes are properly lubricated and replace them if they are damaged.
• Check Shutoffs: Check your shutoffs to make sure no fluid is getting by. 
• Oil Consumption Rate: Ensure oil consumption rate is the same as in regular operation, which is 16-17 hours of pumping per gallon of oil.

Rotary vane pumps are a cornerstone in the world of truck-mounted vacuum pumps due to their simplicity, durability, and efficiency in creating high levels of vacuum and pressure. Basic, regular maintenance and troubleshooting are essential to ensure optimal performance of the pump and longevity. The Fruitland rotary vane line stands out as a premier choice in this category, delivering unmatched quality and toughness.

For truck builders and operators looking for reliable, easy-to-operate vacuum pumps, the rotary vane pump remains a top choice, ready to meet the demanding needs of various applications across industries. To locate Fruitland brand rotary pumps, visit our Find a Dealer section.