Changing the Rotation of a Viking Pump Gear Pump

Do you need to change the rotation of a gear pump? This guide will help you determine how to handle this situation.

If you need assistance, our application engineers are glad to help!  Please contact us for assistance with your specific pump.

Unlike centrifugal pumps, many gear pumps work equally well in both directions. However, it is important to identify if your pump can safely be reversed and determine any modifications to safely and correctly reverse rotation.    

If you need to identify the correct rotation of your pump, be sure to check our our guide and information sheets on identifying gear pump rotation.

Can I reverse the rotation of my gear pump?

Often – but not always! Most internal gear pumps can pump in either direction, with the shaft determining the suction and discharge port. However, there are some exceptions. In particular, if he pump has a relief valve it is important the relief valve be oriented correctly for the rotation.   There are also some cases where the design of the pump requires a specific rotation.

Many Viking pumps which cannot be reversed will have a rotation arrow on the casting or nameplate, though caution should be used especially with older pumps where the rotation arrow may no longer be visible. 

Example of Gear Pumps Where Rotation Can NOT be Reversed

Viking gear pumps which rotation cannot be reversed

  • Magnetically driven (seal-less) pumps, such as Viking 895 Series
  • Some Motor Speed Pumps from the 4195 series (generally 3” ports and larger)  
  • Spur Gear (SG) Pumps: Spur gear pumps are generally built in either clockwise or counterclockwise rotation and cannot be modified because they have internal lubrication paths. In cases where the rotation needs to be changed, however, the entire pump body can be rotated to move the suction and discharge ports.  
  • Pumps with different sized inlet and outlet: Inlet is larger than the outlet.
  • Relief valve is built into the casing such as Viking C, F, and FH 432 Pumps with internal RV.
  • Pumps which cannot be reversed will often have a rotation arrow on the nameplate or casting.
Viking Pump Gear Pumps Where Rotation Can Be Reversed With Modifications

Viking Pump gear pumps which can be reversed with modifications

  • Pumps with Relief Valves bolted to the pump body or head. See the Installation and Operations Manual of your pump for instructions about how to correctly reverse the relieve valve to change rotation. 
  • Pumps with seal circulation plans can often be reversed, however the circulation plan may require modification.  
  • Pumps with drilled idler pins or casing grooves should be evaluated to determine if they are suitable for reversal. Contact your distributor for more assistance.
Viking Pump Gear Pumps Where Rotation Can Be Reversed

Viking pumps which can be reversed, often without modification

  • Viking pumps without rotation arrows on either the casting or nameplate, and without internal relief valves.     
  • *Use Caution, especially with on older pumps* We recommend checking the Installation, Operations, and Maintenance Manual to confirm that pump rotation can be reversed or contact us for further assistance. 

Learn More! Viking Pump teaches how to evaluate if your pump can be reversed: