Heater/Circulator - Weak Water Flow

An analyst turned our 708-DS Agilent Dissolution Bath and when they initialized the system today, the error message heater air pocket or Heater OFF appeared.

I primed our pump G7986A and the temperature came back to increase and stabilized at 37°C. However, I noticed the flow coming out is really weak in comparison to another Agilent disso we have. I almost can not see the pump is working, even all the lights are green. When I prime I can see the flow is stronger, but 30 seconds later I cannot see the water flow anymore.

Is there any part in the pump that would be needed to be replaced?

Thank you so much.

Have a nice day.

Best regards,


  • If the red Heater Error LED was triggered then it could be caused by an air pocket.  Did the error light go off after priming?  If it is not circulating and priming does not resolve the issue then I would recommend contacting your local service team (with the serial number) in regards to repair or exchange options.

  • Hello Suzany,

    i would suggest you to turn the pump on the side before to turn it on. The inlet on the pump should be downward, and the outlet upward. In this way , when you turn the pump on the air bubble stucked within the pump will be able to go out.

     Best Regards,


  • After priming the error went off and the temperature is stable, but when you look by the water bath deflector generally I can see the water flow, but for this dissolution bath in specific I'm not able to. I'm just worried the homogeneity in the water bath will not be good because of this. Later on, I will test and verify the temperature in the vessel. 

    Thank you so much for your answer. I really appreciated it.

  • Hi Bryan,

    I turned the pump with the arrow downwards. The error went off and the temperature is stable. Now I will follow-up the temperature in each vessel to see if the homogeneity in the bath is ok.

    Thank you so much for your answer. I really appreciated it.

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