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Air Operated Diaphragm Pump Troubleshooting

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    What are the main reasons for the malfunction of an Air Operated Diaphragm Pump?

    To ensure safe operation and the life of the pump and to form part of a preventative maintenance schedule, routine and complete inspection of the pump is recommended. Routine Inspection can be done by frequent observation of the pump operation is required to detect problems.

    A change in sound of the running of the pump can be an indication of wearing parts as well as leakages and changes in performance. The intervals for a complete inspection depend upon the operation conditions of the pump. The characteristics of the liquid, temperature, materials used in the pump and running time decide how often a complete inspection is necessary. Nevertheless, Tapflo recommend that customers should inspect their pump at least once a year.

    As part of this inspection, Air and Liquid Kits should be changed and Valve Kits should be changed once every 2 years. Tapflo recommends stocking at least a Liquid and Air Kit to ensure that expensive down time is avoided.

    Problem Possible Fault Possible Solution
    The pump does not run The air pressure is to low Increase air pressure via a filter-regulator
    The air connection is blocked Check/clean air supply connection
    Muffler is blocked Check/clean/replace muffler
    Air valve is defective Clean/replace complete air valve
    Dirt in the pump chamber Remove debris from the chambers
    Diaphragm breakdown Replace diaphragm
    The suction is bad Suction connection is not tight Tighten the suction line
    Suction connection is blocked Clean suction line
    Muffler is blocked Check/clean/replace muffler
    Valve balls are blocked or damaged Check dimensions and shape of valve balls
    Valve seats are worn. Pump starts with high pressure air in suction/discharge line dry suction against discharge pressure Check dimensions and shape of valve seats. Start the pump slowly (see chapter 2.2 of manual) Vent suction/discharge line, wet the pump/start without discharge pressure
    The Pump runs irregularly Valve balls are blocked Check dimensions and shape of valve balls
    Sealing in centre block, air valve is defective Replace sealing. Clean/repair air valve
    Diaphragm breakdown valve seats are worn icing on the muffler Replace diaphragm. Check dimensions and shape of valve seats. Improve air quality (see chapters 1.7.1 and 2.2.2 of manual)
    Bad flow/pressure





    Pressure fall in air supply. Pressure losses on suction side air supply/air valve leaking Increase air pressure via a filter-regulator. Check/change installation on suction side. Check/repair/replace air supply/air valve.
    Suction or air connection blcoked Check/clean air supply/suction connection
    Muffler is blocked Check/clean/replace muffler
    Valve ball worn or broken. Valve seats are worn Check dimensions and shape of valve balls. Check dimensions and shape of valve seats.
    Air in liquid Seal suction line; check/refill container
    Diaphragm Breakdown. Icing on the muffler Check/replace diaphragms. Improve air quality (see chapters 1.7.1 and 2.2.2 of manual)
    Liquid leaks from the pump Screws on the housing not properly tightened O-ring on manifolds damaged. Damaged diaphragm tension/stress form the installation Check tightening torques of the screws. Replace O-rings. Check/replace diaphragms. Adjust installation, eliminate stress, when using a dampener provide separate support for it (see dampener IOM manual)
    Liquid comes out of the muffler Diaphragm breakdown Replace diaphragm
    Diaphragm breakdown Wrong selection of material. Too high pressure in the installation. Long periods of dry running. Too high pressure on suction side. Contact us for information on material selection. Use air treatment system for protection. When dry, run pump slowly (see chapter 2.2 of manual). Make sure there is pressure balance between the air and liquid side of the diaphragm.
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