Troubleshooting
TT Twin-Screw Pump -
Installation, Operation, and Maintenance Manual
73
Symptom
Cause
Remedy
The pump starts pumping
but then loses suction.
The pump is not fully primed.
Re-prime the pump and check that the pump and
suction line are full of liquid.
The suction line has air or vapor pockets.
Rearrange the piping in order to eliminate air
pockets.
Air leaks into the suction line or pump
Locate the source of the air leak and rectify.
Typical locations are single mechanical seals
(without quench), flange gaskets and valve stem
packings.
Off-gassing of air or vapor from the pumped
liquid
Verify the minimum suction pressure or liquid
level is within specification.
Verify the fluid vapor pressure is within
specification
The pump is worn or damaged.
Inspect and replace the pump if necessary.
The bearings are running
hot.
The pump and driver are not aligned properly.
Realign the pump and driver.
The bearings are worn or damaged
Replace the bearings
The discharge pressure is too high
Bring the discharge pressure to within
specification.
The operating speed is too high
Bring the pump speed to within specification.
There is insufficient lubrication.
Check the lubricant for suitability and level.
The pump is noisy or
vibrates.
The pump and driver are not aligned properly.
Realign the pump and driver.
The pump is worn or damaged.
Inspect and replace the pump if necessary.
The motor has high vibration which is being
transmitted to the pump.
Verify the source of the motor vibration and repair
as needed.
The foundation arrangement is not rigid.
Tighten the hold-down bolts of the pump and
motor. Make sure the baseplate is properly
grouted without voids or air pockets.
The bearings are worn or damaged
Replace the bearings
The suction or discharge piping is not
anchored or properly supported.
Anchor the suction or discharge piping as
necessary according to recommendations in the
Hydraulic Institute Standards Manual.
Relief valve chatter
Adjust relief valve to open at the set pressure
indicated on the pump nameplate.
The suction velocity is too high.
Increase the suction pipe diameter.
The suction lift is too high.
Make sure that the suction-line shutoff valve is
fully open and that the line is unobstructed.
Verify the minimum suction pressure or liquid
level is within specification.
Verify the fluid vapor pressure and viscosity is
within specification
Off-gassing of air or vapor from the pumped
liquid
Verify the minimum suction pressure or liquid
level is within specification.
Verify the fluid vapor pressure is within
specification
Summary of Contents for HOUTTUIN TT Twin-Screw
Page 1: ...TT Twin Screw Pump Installation Operation Maintenance...
Page 2: ......
