ROOTS UNIVERSAL RAI Series, Installation Operation & Maintenance

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©2002 Dresser, Inc. all rights reserved.
ROOTS, RAM, URAI and WHISPAIR are trademarks of Dresser, Inc.
Dresser Design and Universal RAI are registered trademarks of Dresser, Inc.
TROUBLESHOOTING
Trouble Item Possible Cause Remedy
No flow 1 Speed too low Check by tachometer and compare with published
performance
2 Wrong rotation Compare actual rotation with Figure 1 or 2
Change driver if wrong
3 Obstruction in piping Check piping, valves, silencer to assure open flow path
Low capacity 4 Speed too low See item 1, If belt drive, check for slippage and readjust
tension
5 Excessive pressure rise Check inlet vacuum and discharge pressure and compare
with Published performance
6 Obstruction in piping See item 3
7 Excessive slip Check inside of casing for worn or eroded surfaces causing
excessive clearances
Excessive power 8 Speed too high Check speed and compare with published performance
9 Excessive pressure rise See Item 5
10 Impeller rubbing Inspect outside of cylinder for high temperature areas, then
check for impeller contact at these points. Correct blower
mounting, drive alignment
11 Scale, sludge, rust Clean blower appropriately
or product build up
Overheating of 12 Inadequate lubrication Check oil sump levels in gear and drive end headplates
bearing or gears 13 Excessive lubrication Check oil levels. If correct, drain and refill with clean oil of
recommended grade
14 Excessive pressure rise See Item 5
15 Coupling misalignment Check carefully. Realign if questionable
16 Excessive belt tension Readjust for correct tension
Vibration 17 Misalignment See Item 15
18 Impellers rubbing See Item 10
19 Worn bearings/gears Check gear backlash and condition of bearings, and replace
as indicated
20 Unbalanced or rubbing Scale or process material may build up on casing and
impeller impellers, or inside impellers. Remove build-up to restore
original clearances and impeller balance
21 Driver or blower loose Tighten mounting bolts securely
22 Piping resonances Determine whether standing wave pressure pulsations are
present in the piping
23 Scale/sludge build-ups Clean out interior of impeller lobes to restore dynamic
balance
24 Casing strain re-work piping alignment to remove excess strain
Driver stops, or 25 Impeller stuck Check for excessive hot spot on headplate or cylinder.
will not start See item 10. Look for defective shaft bearing and/or
gear teeth
26 Scale, sludge, rust or Clean blower appropriately
product build-up
Excessive breather 27 Broken seal Replace seals
Blow-by or excessive 28 Defective O-ring Replace seals and O-ring
oil leakage to vent area