TM 5-3895-374-24-2 b. Relief valve poppet not seating properly. c. Bypass around the pump partially open. d. Too much extra clearance. e. Pump worn. 3. Fluttering, jumping, or erratic reading - a. Cavitation. b. Liquid coming to pump in slugs. c. Air leak in suction line. d. Vibrating    from    misalignment    or    mechanical problems. Some of the following may also help pinpoint the problem: A.  Pump does not pump. 1. Lost  its  prime  air  leak,  low  level  in  tank,  foot  valve stuck. 2. Suction lift too high. 3. Rotating in wrong direction. 4. Motor does not come up to speed. 5. Suction and discharge valves not open. 6. Strainer clogged. 7. Bypass   valve   open,   relief   valve   set   too   low,   relief valve poppet stuck open. 8. Pump worn out. 9. Any  changes  in  the  liquid  system,  or  operation  that would  help  explain  the  trouble,  e.g.    new  source  of supply,  added  more  lines,  inexperienced  operators, etc. 10. Tighten end clearance. 11. Head position incorrect.  See Fig.  3. B.  Pump starts, then loses its prime. 1. Supply tank empty. 2. Liquid vaporizing in the suction line. 3. Air leaks or air pockets in the suction line; leaking air through packing or mechanical seal. 4. Worn out. C.  Pump is noisy 1. Pump is being starved (heavy liquid cannot get to  pump  fast  enough).    Increase  suction  pipe size or reduce length. 2. Pump   is   cavitating   (liquid   vaporizing   in   the suction   line).      Increase   suction   pipe   size   or reduce   length;   if   pump   is   above   the   liquid, raise the liquid level closer to the pump; if the liquid is above the pump, increase the head of liquid. 3. Check alignment. 4. May     have     a     bent     shaft     or     rotor tooth. Straighten or replace. 5. Relief valve chatter; increase pressure setting. 6. May have to anchor base or piping to eliminate or reduce vibration. 7. May  be  a  foreign  object  trying  to  get  into  the pump through the suction port. D.  Pump not up to capacity. 1. Starving  or  cavitating  increase  suction  pipe  size  or reduce length. 2. Strainer partially clogged. 3. Air leak in suction piping or along pump shaft. 4. Running too slowly; is motor the correct speed and is it wired up correctly. 5. Bypass line around pump partially open. 6. Relief valve set too low or stuck open. 7. Pump worn out. 8. Tighten end clearance. 9. Head position incorrect.  See Fig.  3. E.  Pump takes too much power. 1. Running   too   fast   Is   correct   motor   speed,   reducer ratio, sheave size.  etc.  being used. 2. Is liquid more viscous than unit sized to handle; heat the   liquid,   increase   the   pipe   size,   slow   the   pump down, or get a bigger motor. 3. Discharge   pressure   higher   than   calculated.      check with pressure gauge.  Increase size or reduce length of pipe, reduce speed (capacity), or get bigger motor 4. Packing gland drawn down too tight. 5. Pump misaligned. 6. Extra  clearance   on   pumping   elements   may   not   be sufficient  for  operating  conditions.    Check  parts  for evidence  of  drag  or  contact  in  pump  and  increase clearance where necessary. F.  Rapid Wear. On   most   applications   the   pump   will   operate   for   many months   or   years   before   it   gradually   loses   its   ability   to deliver capacity or pressure.  Examination of such a pump would  show  a  smooth  wear  pattern  on  all  parts.    Rapid wear, occurring in a few minutes, hours or days, shows up as  heavy  grooving,  galling,  twisting,  breaking  or  similar severe signs of trouble.  SEE CHART PAGE 7. PREVENTATIVE MAINTENANCE Performing   a   few   preventative   maintenance   procedures   will extend  the  life  of  your  pump  and  reduce  the  cost  per  gallon pumped. A. Lubrication Grease all zerks after every 500 hours of operation or after 60 days,  whichever  occurs  first.    If service  is  severe,  grease  more  often.    Do  it  gently with  a  hand  gun.    Use  a  #2  ball  bearing  grease  for normal applications.  For hot or cold applications use appropriate grease.  See Engineering Service Bulletin ESB-515. B. Packing  Adjustment  Occasional  packing  adjustment may be required to keep leakage to a slight weep:  if impossible   to   reduce   leakage   by   gentle   tightening, replace packing or use different type.  See Technical Service Manual on particular model series for details on repacking. C. End   Clearance   Adjustment   After   long   service   the running clearance between the end of the rotor teeth and  the  head  may  have  increased  through  wear  to the    point    where    the    pump    is    losing    capacity    or pressure.       Resetting    end    clearance    will    normally improve  pump  performance.    See  TSM  on  particular model series for procedure on adjusting end clearance for pump involved. D. Examine Internal Parts Periodically remove the head, examine idler and bushing and head and pin for wear. Replacing  a  relatively  inexpensive  idler  bushing  and idler  pin  after  only  moderate  wear  will  eliminate  the need to replace more expensive parts at a later date. See TSM on particular model series for procedure in removing  head  of  the  pump.    Be  sure  idler  does  not slide  off  idler  pin  as  head  is  removed  and  drop  and hurt someone or damage the part. E. Cleaning the Pump A clean pump is easier to inspect, lubricate,   adjust,   and   runs   cooler:      plus,   it   looks better. F. Storage If a pump is to be out of service or stored for a long time, drain it and protect it from rusting inside and out. page 3 - 1207