If the circuit breaker is off, the cause of the overload may be shorted wiring, shorted motor windings; or a short in the pressure sensitive switch.

Dehydrator stops and starts repeatedly before reaching preset transmission line pressure:

  • Check for large leaks in the transmission line or connecting line tubing.

  • Check the connecting line tubing for restrictions such as kinks. Reroute the tubing to remove kinks.

  • Check to see if the transmission line is too restrictive for the pressure delivered by the dehydrator; that is, the dehydrator produces more pressure than the line can handle. If the line is too restrictive, connect a pressure regulating tank between the dehydrator and the line. The tank outlet pressure can then be adjusted to suit the transmission line.

    Dehydrator runs excessively - 30% to 50% more than normal:

  • Check the dehydrator running time and frequency of operation. An antenna system incorporating an automatic dehydrator should be designed so that the dehydrator runs no more than 72 minutes and no less than 10 minutes during a 24-hour period. If the running time is longer or operation occurs more frequently, there is major leakage in the system.

  • Check for external or internal leakage. Disconnect the connecting line tubing from the dehydrator outlet, block the outlet with your finger, and run the dehydrator. The dehydrator should shut off at the preset pressure of 8 psi within one minute. If it does, the leakage is either in the connecting line or transmission line. If the dehydrator continues to run after one minute, there is internal leakage.

  • Check the dehydrator for internal leaks. Cap the outlet, run the dehydrator, and apply a soap solution at all fittings and around components.
  • Check components such as the back pressure valve, pressure sensitive switch, humidity indicator, and the pressure gauge. Bubbling indicates leakage. Tighten leaky fittings and replace leaky components. Then recheck operation with the outlet capped; it should shut off at 8 psi within one minute.

    Dehydrator either does not start at pressure of 3 psi or shut off at 8 psi:

  • Readjust the limits of or replace the pressure sensitive switch.

    System pressure does not increase when compressor runs:

  • Readjust or replace the back pressure regulator valve.
  • Replace the motor-compressor unit or rebuild the compressor using compressor repair kit 40486.

    Color of humidity indictor either pink, brown, or white:

  • Measure the delivery air flow rate. It should be at least 10 to 12 cubic feet per hour. A flow rate that is too low or too high indicates that the back pressure regulator valve needs readjustment or it is defective. If this adjustment or replacement does not affect the flow rate, the compressor should be repaired or replaced.

  • Check solenoid valve cycle time. Incorrect cycle timing is caused by a defective solenoid timing motor or solenoid switch.

  • Run the dehydrator for 12 hours and check the humidity indictor. If there is little or no color change, replace the dryer assembly. (The dryer assembly includes the solenoid valves.)



  • Andrew Corporation 10500 W. 153rd St.
    Orland Park, IL U.S.A. 60462
    Andrew Antennnas
    Weybridge, Surrey, Great Britain
    Andrew Antenna Company Ltd.
    Whitby, Ontario, Canada
    Andrew Antennas
    Campbellfield, Victoria, Australia
    Andrew AG
    Zurich, Switzerland
    Andrew & Cia.
    Sorocaba, SP, Brazil
    Antenas de Tramsmisión S.A. de C.V.
    México, D.F. México
    Antennes Andrew S.A.R.L.
    Buc, France
    Andrew Corporation
    Tokyo, Japan
    Andrew S.R.L.
    Milan, Italy

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    PRINTED IN U.S.A.
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