4 Common Signs of Glycol Pump Failure

The Kimray Glycol Pump is used to control triethylene glycol circulation in gas dehydration systems.

In this video, we examine some internal parts of the glycol pump that have been damaged during operation.  

We then explain what these parts may be telling us about the cause of the damage and offer some solutions to prevent further damage.  

1. Scratches on the Piston Rod

The cause for this scratching is likely some sort of trash or debris in the dehydration system that has made its way through the pump.  

You can either sand this piston rod down or replace it. If you sand it, use 120 emery cloth but be careful to not sand it too much. If the outer diameter becomes too small, the O-ring will not seal correctly. As a general rule, if you can still feel the scratch with your fingernail, it’s sharp enough to cut an O-ring, so the rod needs to be replaced. 

Solution: Use finer filters or possibly change your filters more often. There’s typically one filter on the suction side of the pump and one filter on the tower.  

We suggest changing your filters at a minimum of once a month. 

2. Excessive Wearing on the Middle of the Piston Rod

Excessive wear in the middle of a piston rod is due to the pump short stroking, meaning it is not stroking at its entire capacity. 

There are four common causes of short stroking:  

  1. Trash has gotten in the system and cut the O-rings causing the wet and dry glycol are mixing.
    Solution: Change filter or go to a finer filter element. 
  2. The pump and dehydration system were not started up properly.
    Solution: Re-start your dehydration system, slowly opening your main valve to make sure the glycol pump is stroking evenly. 
  3. The dart got stuck in the dart cap, causing the pump to skip.
    • This can happen if your pump sits to long between operation or the glycol gets contaminated.
      Solution: Take the caps off and clean the dart and caps and make sure they move freely. (Note: If you have a standby pump, we recommend starting it up every quarter to get fresh glycol in the system, so the dart doesn’t get stuck.)
    • The darts also get stuck due to excessive wear in the caps or on dart stems, which create too much side-to-side play.
      Solution: Change the dart or cap or both. 
    • Another cause for the darts getting stuck is if debris such as Teflon tape, grass or straw have become wedged between the dart and seat area. You will need to clean the dart and seat area and make sure they move freely.
      Solution: Proper filtration. 
  4. A fourth cause of short stroking is excessive wear on the cylinder, which will cause wet and dry glycol to mix. This wear is caused by long-term use.
    Solution: Replaced the cylinder. If scratches are present, also check for proper filtration.

3. Broken Pilot Piston

The cause of a broken pilot piston is that the system lost suction at some point and pumped dry. This may have happened because of a poor startup and no glycol return, or because an O-ring was cut.  

Another cause may be that you are losing glycol. This can happen if the pH in the glycol is off, causing it to foam and go out the top of the contactor and into sales line rather than staying in the system.  

Solution: Clean and steam your dehydration system.   

4. Condensate Getting into the Pump

An important word of caution—this condensate is extremely flammable. You need to keep this out of the reboiler to prevent possible combustion.

The cause for condensate getting into the pump is a problem with the flash separator, or the absence of one altogether. 

One indicator is if condensate drops out of the pump right when you remove the plugs. 

Another sign of condensate is if the O-rings have swelled, making it difficult to remove the seats from the suction block or to remove the cylinders. The O-rings on the darts may be missing entirely because of contact with the condensate.  

Solution: Check the operation of the flash separator. If one does not exist, consider installing a flash separator in your system. 

If you’d like to request a site visit or in-person training on your glycol dehydration system, contact your local Kimray representative or authorized distributor.  


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Mark Anderson serves as a Product and Applications Trainer at Kimray.