Dresser ROOTS RAM 400 Series Owner's manual

INSTALLATION OPERATION MAINTENANCE
US $3.00, Canada $4.50
RAM™and RCS (400 & 600 RCS Vertical WHISPAIR™
Only) – GAS, DVJ, DPJ and VJ Series Blowers
JMake sure both driving and driven equipment is cor-
rectly lubricated before start-up. See LUBRICATION.
JIn event of trouble during installation or operation, do
not attempt repairs of Roots furnished equipment. Notify
Roots, giving all nameplate information plus an outline
of operating conditions and a description of the trouble.
Unauthorized attempts at equipment repair may void
Roots warranty.
JUnits out of warranty may be repaired or adjusted by the
owner. Good inspection and maintenance practices
should reduce the need for repairs.
NOTE: Information in this manual is correct as of the date of
publication. Roots reserves the right to make design or
material changes without notice, and without obligation to
make similar changes on equipment of prior manufacture.
For your nearest Roots Office, dial our Customer Service Hot
Line toll free; 1-877-363-ROOT(S) (7668) or direct 832-590-
2600.
Do These Things To Get The Most From Your ROOTS™blower
Contents
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . 1 - 12
Information Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Safety Precautions & Operating Limitations . . . . . . . . . . . . 3
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 9
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Inspection & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 11
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
JCheck shipment for damage. If found, file claim with
carrier and notify Roots.
JUnpack shipment carefully, and check contents against
Packing List. Notify Roots if a shortage appears.
JStore in a clean, dry location until ready for installation.
Lift by methods discussed under INSTALLATION to
avoid straining or distorting the equipment. Keep covers
on all openings. Protect against weather and corrosion if
outdoor storage is necessary. See page 4 for instruc-
tions.
JRead OPERATING LIMITATIONS and INSTALLATION sec-
tions in this manual and plan the complete installation.
JProvide for adequate safeguards against accidents to
persons working on or near the equipment during both
installation and operation. See SAFETY PRECAUTIONS.
JInstall all equipment correctly. Foundation design must
be adequate and piping carefully done. Use recommend-
ed accessories for operating protection.
GAS BLOWER SECTION . . . . . . . . . . . . . . . . . . . . . . .13 - 14
DVJ BLOWER SECTION . . . . . . . . . . . . . . . . . . . . . . . 15 - 18
Internal Abradable Coating . . . . . . . . . . . . . . . . . . . . .17 - 18
406 RAM DPJ BLOWER SECTION . . . . . . . . . . . . . . . . . . 19
VJ BLOWER SECTION . . . . . . . . . . . . . . . . . . . . . . . .20 - 24
Installation Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 - 24
Parts Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 - 27
ISRB-2000 rev.0807

2
Roots products are sold subject to the
current General Terms of Sale, GTS-5001 and
Warranty Policy WP-5020. Copies are
available upon request.
Contact your local Roots Office
or Roots Customer Service
Hot Line 1-877-363-ROOT(S) (7668)
or direct 832-590-2600.

3For your nearest Roots office contact information, please consult the last page of this document.
Safety Precautions
It is important that all personnel observe safety precautions
to minimize the chances of injury. Among many considera-
tions, the following should be particularly noted:
• Blower casing and associated piping or accessories may
become hot enough to cause major skin burns on con-
tact.
• Internal and external rotating parts of the blower and
driving equipment can produce serious physical injuries.
Do not reach into any opening in the blower while it is
operating, or while subject to accidental starting. Protect
external moving parts with adequate guards.
• Disconnect power before doing any work, and avoid
bypassing or rendering inoperative any safety or protec-
tive devices.
• If blower is operated with piping disconnected, place a
strong coarse screen over the inlet and avoid standing in
the discharge air stream. CAUTION: Never cover the
blower inlet with your hand or other part of body.
• Stay clear of inlet and discharge openings.
• Stay clear of the blast from pressure relief valves and
the suction area of vacuum relief valves.
• Use proper care and good procedures in handling, lift-
ing, installing, operating and maintaining the equipment.
• Casing pressure must not exceed 25 PSI (1725 mbar)
gauge. Do not pressurize vented cavities from an exter-
nal source, nor restrict the vents without first consulting
Roots.
• Do not use air blowers on explosive or hazardous gases.
• Other potential hazards to safety may also be associated
with operation of this equipment. All personnel working
in or passing through the area should be trained to exer-
cise adequate general safety precautions.
Operating Limitations
A ROOTS blower or exhauster must be operated within certain
approved limiting conditions to enable continued satisfactory
performance. Warranty is contingent on such operation.
Maximum limits for pressure, temperature and speed are
specified in TABLE 1a, page14 in the GAS Section, TABLE 1b,
page 15 in the DVJ Section, TABLE 1c, page 19 in the DPJ
Section and TABLE 1d, page 20 in the VJ Section for allow-
able speeds for various models & sizes of blowers and
exhausters. These limits apply to all units of normal con-
struction, when operated under standard atmospheric condi-
tions. Be sure to arrange connections or taps for instruments
such as thermometers and pressure or vacuum gauges at or
near the inlet and discharge connections of the unit. These,
along with a tachometer, will enable periodic checks of oper-
ating conditions.
PRESSURE – The pressure rise, between inlet and discharge,
must not exceed the figure listed for the specific unit frame
size concerned. Also, in any system where the unit inlet is at
a positive pressure above atmosphere a maximum case rat-
ing of 25 PSI gauge (1725 mbar) should not be exceeded
without first consulting Roots. Never should the maximum
allowable differential pressure be exceeded.
On vacuum service, with the discharge to atmospheric pres-
sure, the inlet suction or vacuum must not be greater than
values listed for the specific frame size.
TEMPERATURE – Blower & exhauster frame sizes are
approved only for installations where the following tempera-
ture limitations can be maintained in service:
• Measured temperature rise must not exceed listed val-
ues when the inlet is at ambient temperature. Ambient is
considered as the general temperature of the space
around the unit. This is not outdoor temperature unless
the unit is installed outdoors.
• If inlet temperature is higher than ambient, the listed
allowable temperature rise values must be reduced by
2/3 of the difference between the actual measured inlet
temperature and the ambient temperature.
• The average of the inlet and discharge temperature must
not exceed 250°F. (121°C).
• The ambient temperature of the space the blower/motor
is installed in should not be higher than 120°F (48.8°C).
SPEED – These blowers & exhausters may be operated at
speeds up to the maximum listed for the various frame sizes.
They may be direct coupled to suitable constant speed driv-
ers if pressure/temperature conditions are also within limits.
At low speeds, excessive temperature rise may be a limiting
factor.
Special Note: The listed maximum allowable temperature rise
for any particular blower & exhauster may occur well before
its maximum pressure or vacuum rating is reached. This
may occur at high altitude, low vacuum or at very low speed.
The units’ operating limit is always determined by the maxi-
mum rating reached first. It can be any one of the three:
Pressure, Temperature or Speed.

4
Before operating a blower under power for the first time,
recheck the unit and the installation thoroughly to reduce the
likelihood of avoidable troubles. Use the following procedure
check list as a guide, but consider any other special condi-
tions in the installation.
1. Be certain that no bolts, tools, rags, or debris have been
left in the blower air chamber or piping.
2. If an outdoor intake without filter is used, be sure the
opening is located so it cannot pick up dirt and is pro-
tected by a strong screen or grille. Use of the temporary
protective screen as described under INSTALLATION is
strongly recommended.
3. Recheck blower leveling, drive alignment and tightness
of all mounting bolts if installation is not recent. If belt
drive is used, adjust belt tension correctly.
4. Turn drive shaft by hand to make sure impellers still
rotate without bumping or rubbing at any point.
5. Ensure oil levels in the main oil sumps are correct.
6. Check lubrication of driver. If it is an electric motor, be
sure that power is available and that electrical overload
devices are installed and workable.
7. Open the manual unloading valve in the discharge air
line. If a valve is in the inlet piping, be sure it is open.
8. Bump blower a few revolutions with driver to check that
direction of rotation agrees with arrow near blower
shaft, and that both coast freely to a stop.
After the preceding points are cleared, blower is ready for
trial operation under “no-load” conditions. The following
procedure is suggested to cover this initial operation test
period.
a. Start blower, let it accelerate to full speed, then shut
off. Listen for knocking sounds, both with power on
and as speed slows down.
b. After blower comes to a complete stop, repeat
above, but let blower run 2 or 3 minutes. Check for
noises, such as knocking sounds.
c. After blower comes to a complete stop, operate
blower for about 10 minutes unloaded. Check oil
levels. Observe cylinder and headplate surfaces for
development of hot spots such as burned paint,
indicating impeller rubs. Be aware of any noticeable
increase in vibration.
Assuming that all trials have been satisfactory, or that neces-
sary corrections have been made, the blower should now
have a final check run of at least one hour under normal
operating conditions. After blower is restarted, gradually
close the discharge unloading valve to apply working pres-
sure. At this point it is recommended that a pressure gauge
or manometer be connected into the discharge line if not
already provided, and that thermometers be in both inlet and
discharge lines. Readings from these instruments will show
whether pressure or temperature ratings of the blower are
being exceeded.
During the final run, check operating conditions frequently
and observe the oil levels at reasonable intervals. If excessive
noise or local heating develops, shut down immediately and
determine the cause. If either pressure rise or temperature
rise across the blower exceeds the limit specified in this
manual, shut down and investigate conditions in the piping
system. Refer to the TROUBLESHOOTING CHECKLIST for
suggestions on various problems that may appear.
The blower should now be ready for continuous duty opera-
tion at full load. During the first few days make periodic
checks to determine whether all conditions remain steady, or
at least acceptable. This may be particularly important if the
blower is supplying air to a process system where conditions
can vary. At the first opportunity, stop the blower and clean
the temporary inlet protective screen. If no appreciable
amount of debris has collected, the screen may be removed.
See comments under INSTALLATION. At this same time, veri-
fy leveling, coupling alignment or belt tension, and mounting
bolt tightness.
Should operating experience prove that blower capacity is a
little too high for the actual air requirements, a small excess
may be blown off continuously through the manual unload-
ing or vent valve. Never rely on the pressure relief valve as
an automatic vent. Such use may cause the discharge pres-
sure to become excessive, and can also result in failure of
the valve itself. If blower capacity appears to be too low, refer
to the TROUBLESHOOTING CHECKLIST. See pages 15 and
19 for additional troubleshooting information regarding DVJ
and DPJ units.
Vibration Assessment Criteria
With measurements taken at the bearing locations on the
housings, see chart below for an appropriate assessment
guide for rotary lobe blowers rigidly mounted on stiff foun-
dations.
In general, blower vibration levels should be monitored on a
regular basis and the vibration trend observed for progres-
sive or sudden change in level. If such a change occurs, the
cause should be determined through spectral analysis.
As shown on the chart below, the level of all pass vibration
will determine the need to measure discrete frequency vibra-
tion levels and the action required.
Operation
All Pass Vibration Discrete Frequency Action
(in/sec) Vibration (in/sec)
0.45 or less N/R Acceptable
Greater than 0.45 0.45 or less @ Acceptable
but 1.0 or less any frequency
Greater than 0.45 @ Investigate
any frequency
Greater than 1.0 Less than 1.0 Investigate
Greater than 1.0 Investigate

5For your nearest Roots office contact information, please consult the last page of this document.
ROOTS blowers & exhausters are treated after factory
assembly to protect against normal atmospheric corrosion.
The maximum period of internal protection is considered to
be one year under average conditions, if shipping plugs &
seals are not removed. Protection against chemical or salt
water atmosphere is not provided. Avoid opening the unit
until ready to start installation, as corrosion protection will
be quickly lost due to evaporation.
If there is to be an extended period between installation and
start up, the following steps should be taken to ensure corro-
sion protection. See “Cleaning & Preservation” on pages 17
and 18 for DVJ and DPJ units.
JCoat internals of cylinder, gearbox and drive end bearing
reservoir with Nox-Rust VCI-10 or equivalent. Repeat
once a year or as conditions may require. Nox-Rust VCI-
10 is petroleum soluble and does not have to be
removed before lubricating. It may be obtained from
Daubert Chemical Co., 2000 Spring Rd., Oak Brook, Ill.
60521.
JPaint shaft extension, inlet and discharge flanges, and all
other exposed surfaces with Nox-Rust X-110 or equiva-
lent.
JSeal inlet, discharge, and vent openings. It is not recom-
mended that the unit be set in place, piped to the sys-
tem, and allowed to remain idle for extended periods. If
any part is left open to the atmosphere, the Nox-Rust
VCI-10 vapor will escape and lose its effectiveness.
JProtect units from excessive vibration during storage.
JRotate shaft three or four revolutions every two weeks.
JPrior to start up, remove flange covers on both inlet and
discharge and inspect internals to insure absence of
rust. Check all internal clearances. Also, at this time,
remove gearbox and drive end bearing cover and inspect
gear teeth and bearings for rust.
Because of the completely enclosed unit design, location of
the installation is generally not a critical matter. A clean, dry
and protected indoor location is preferred. However, an out-
door location will normally give satisfactory service.
Important requirements are that the correct grade of lubricat-
ing oil be provided for expected operating temperatures, and
that the unit be located so that routine checking and servic-
ing can be performed conveniently. Proper care in locating
driver and accessory equipment must also be considered.
Supervision of the installation by a Roots Service Engineer is
not usually required for these units. Workmen with experi-
ence in installing light to medium weight machinery should
be able to produce satisfactory results. Handling of the
equipment needs to be accomplished with care, and in com-
pliance with safe practices. Unit mounting must be solid,
without strain or twist, and air piping must be clean, accu-
rately aligned and properly connected.
Bare-shaft Units: Two methods are used to handle a unit
without base. One is to use lifting lugs bolted into the top
Installation
of the unit headplates. Test them first for tightness and
fractures by tapping with a hammer. In lifting, keep the
direction of cable pull on these bolts as nearly vertical as
possible. If lifting lugs are not available, lifting slings may
be passed under the cylinder adjacent to the headplates.
Either method prevents strain on the extended drive shaft.
Packaged Units: When the unit is furnished mounted on a
baseplate, with or without a driver, use of lifting slings pass-
ing under the base flanges is required. Arrange these slings
so that no strains are placed on the unit casing or mounting
feet, or on any mounted accessory equipment. DO NOT use
the lifting lugs in the top of the unit headplates.
Before starting the installation, remove plugs, covers or seals
from unit inlet and discharge connections and inspect the
interior completely for foreign material. If cleaning is
required, finish by washing the cylinder, headplates and
impeller thoroughly with an appropriate solvent. Turn the
drive shaft by hand to make sure that the impellers turn
freely at all points. Anti-rust compound on the connection
flanges and drive shaft extension may also be removed at
this time with the same solvent. Cover the flanges until ready
to connect piping.
Mounting
Care will pay dividends when arranging the unit mounting.
This is especially true when the unit is a “bare-shaft” unit
furnished without a baseplate. The convenient procedure
may be to mount such a unit directly on a floor or small con-
crete pad, but this generally produces the least satisfactory
results. It definitely causes the most problems in leveling and
alignment and may result in a “Soft Foot” condition. Correct
soft foot before operation to avoid unnecessary loading on
the casing and bearings. Direct use of building structural
framing members is not recommended.
For blowers without a base, a well anchored and carefully
leveled steel or cast iron mounting plate is recommended.
The plate should be at least 1 inch (25 mm) thick, with its
top surface machined flat, and large enough to provide level-
ing areas at one side and one end after the unit is mounted.
It should have properly sized studs or tapped holes located
to match the unit foot drilling. Proper use of a high quality
machinist’s level is necessary for adequate installation.
With the mounting plate in place and leveled, set the unit on
it without bolting and check for rocking. If it is not solid,
determine the total thickness of shims required under one
foot to stop rocking. Place half of this under each of the
diagonally-opposite short feet, and tighten the mounting
studs or screws. Rotate the drive shaft to make sure the
impellers turn freely. If the unit is to be direct coupled to a
driving motor, consider the height of the motor shaft and the
necessity for it to be aligned very accurately with the unit
shaft. Best unit arrangement is directly bolted to the mount-
ing plate while the driver is on shims of at least 1/8 inch
(3mm) thickness. This allows adjustment of motor position
in final shaft alignment by varying the shim thickness.
Aligning
When unit and driver are factory mounted on a common
baseplate, the assembly will have been properly aligned and

6
mm) total indicator reading, taken on the two coupling hubs.
Maximum deviation from parallel of the inside coupling faces
should not exceed .001” (.03 mm) when checked at six
points around the coupling.
When a unit is BELT DRIVEN, the proper selection of sheave
diameters will result in the required unit speed. When select-
ing a sheave to be fitted to the blower shaft ROOTS recom-
mends a taper lock style sheave to insure proper contact with
the blower shaft. This flexibility can lead to operating temper-
ature problems caused by unit speed being too low. Make
sure the drive speed selected is within the allowable range for
the specific unit size, as specified under TABLE 1a, page 14 in
the GAS Section, TABLE 1b, page 15 in the DVJ Section,
TABLE 1c, page 19 in the DPJ Section, and TABLE 1d, page
20 in the VJ Section.
Belt drive arrangements should employ two or more 3V, 5V,
or 8V-belts running in grooved sheaves. Installation of the
driver is less critical than for direct coupling, but its shaft
must be level and parallel with the unit shaft. The driver
should be mounted on the inlet side of a vertical unit (hori-
zontal piping) and on the side nearest to the shaft on a hori-
zontal unit. (See page 7 for acceptable V belt drive configu-
rations.) The driver must also be mounted on an adjustable
base to permit installing, adjusting and removing the V-belts.
To position the driver correctly, both sheaves need to be
mounted on their shafts and the nominal shaft center dis-
tance known for the belt lengths to be used.
is to be treated as a unit for leveling purposes. Satisfactory
installation can be obtained by setting the baseplate on a con-
crete slab that is rigid and free of vibration, and leveling the
top of the base carefully in two directions so that it is free of
twist. The slab must be provided with suitable anchor bolts.
The use of grouting under and partly inside the leveled and
shimmed base is recommended.
It is possible for a base-mounted assembly to become twist-
ed during shipment, thus disturbing the original alignment.
For this reason, make the following checks after the base has
been leveled and bolted down. Disconnect the drive and
rotate the unit shaft by hand. It should turn freely at all
points. Loosen the unit foot hold-down screws and determine
whether all feet are evenly in contact with the base. If not,
insert shims as required and again check for free impeller
rotation. Finally, if unit is direct coupled to the driver, check
shaft and coupling alignment carefully and make any neces-
sary corrections.
In planning the installation, and before setting the unit, con-
sider how piping arrangements are dictated by the unit
design and assembly. Drive shaft rotation must be estab-
lished accordingly and is indicated by an arrow near the
shaft.
Typical arrangement on vertical units has the drive shaft at
the top with counterclockwise rotation and discharge to the
left. Horizontal units are typically arranged with the drive
shaft at the left with counterclockwise rotation and discharge
down. See drawings on page 9, for other various unit
arrangements and possible conversions.
When a unit is DIRECT COUPLED to its driver, the driver RPM
must be selected or governed so as not to exceed the maxi-
mum speed rating of the unit. Refer to TABLE 1a, page14 in
the GAS Section, TABLE 1b, page 15 in the DVJ Section,
TABLE 1c, page 19 in the DPJ Section and TABLE 1d, page
20 in the VJ Section for allowable speeds of various unit
sizes.
A flexible type coupling should always be used to connect the
driver and unit shafts.
When direct coupling a motor or engine to a blower you must
ensure there is sufficient gap between the coupling halves
and the element to prevent thrust loading the blower bear-
ings. When a motor, engine or blower is operated the shafts
may expand axially. If the coupling is installed in such a man-
ner that there is not enough room for expansion the blower
shaft can be forced back into the blower and cause the
impeller to contact the gear end headplate resulting in dam-
age to the blower. The two shafts must be in as near perfect
alignment in all directions as possible, and the gap must be
established with the motor armature on its electrical center if
end-play exists. Coupling manufacturer’s recommendations
for maximum misalignment, although acceptable for the cou-
pling are normally too large to achieve smooth operation and
maximum life of the blower.
The following requirements of a good installation are recom-
mended. When selecting a coupling to be fitted to the blower
shaft ROOTS recommends a taper lock style coupling to
ensure proper contact with the blower shaft. Coupling halves
must be fitted to the two shafts with a line to line thru .001”
interference fit. Coupling halves must be warmed up per cou-
pling manufacturer’s recommendations. Maximum deviation
in offset alignment of the shafts should not exceed .005” (.13
NOTE: Arc of sheave belt contact on the smaller sheave not to be less than 170°.
Driver to be installed on the inlet side for vertical units, and on the drive shaft side for
horizontal units.
ROOTS recommends the use of two or more 3V, 5V or 8V matched set or banded belts
and sheaves.
Allowable Overhung Loads for V-belt Drives 400 - 600 RAM and
400 - 600 RCS-V units for DVJ, DPJ and VJ Blowers
Frame
Size
404, 406,
409, 412, 418
616, 624
Belt Pull (lbs.) = 275000* Motor HP
__________________________
Blower RPM * Sheave Diameter
Shaft Load (lb. in.)= Belt Pull * (A+1/4”+ )
Sheave Width
___________
2
Standard
Unit
2.11
2.67
Max. Allowable
Shaft Load
(lb.-in.)
3,200
7,975
Dimension “A”
A1/4" Max
Minimum
Sheave
Diameter
7.10
8.50

7For your nearest Roots office contact information, please consult the last page of this document.
Acceptable Blower
Drive Arrangement Options
ACCEPTABLE UNACCEPTABLE

8
CAUTION: Drive couplings and sheaves (pulleys) should have
an interference fit to the shaft of the blower (set screw types
of attachment generally do not provide reliable service.) It is
recommended that the drive coupling or sheave used have a
taper lock style bushing which is properly sized to provide the
correct interference fit required. Drive couplings, that require
heating to fit on the blower shaft, should be installed per cou-
pling manufacturer recommendations. A drive coupling or
sheave should not be forced on to the shaft of the blower as
this could affect internal clearances resulting in damage to
the blower.
Engine drive applications often require special considera-
tion to drive coupling selection to avoid harmful torsional
vibrations. These vibrations may lead to blower damage if
not dampened adequately. It is often necessary to install a
fly-wheel and/or a torsionally soft elastic element coupling
based on the Engine manufacturer recommendations.
The driver sheave should also be mounted as close to its
bearing as possible, and again should fit the shaft correctly.
Position the driver on its adjustable base so that 2/3 of the
total movement is available in the direction away from the
unit, and mount the assembly so that the face of the sheave
is accurately in line with the unit sheave. This position mini-
mizes belt wear, and allows sufficient adjustment for both
installing and tightening the belts. After belts are installed,
adjust their tension in accordance with the manufacturer’s
instructions. However, only enough tension should be applied
to prevent slippage when the unit is operating under load.
Excessive tightening can lead to early bearing concerns or
shaft breakage.
Before operating the drive under power to check initial belt
tension, first remove covers from the unit connections. Make
sure the interior is still clean, then rotate the shaft by hand.
Place a coarse screen over the inlet connection to prevent
anything being drawn into the unit while it is operating, and
avoid standing in line with the discharge opening. Put oil in
the sumps per instructions under LUBRICATION.
Piping
Before connecting piping, remove any remaining anti-rust
compound from Unit connections. Clean pipe should be no
smaller than unit connections. In addition, make sure it is free
of scale, cuttings, weld beads, or foreign material of any
kind. To further guard against damage to the unit, especially
when an inlet filter is not used, install a substantial screen of
16 mesh backed with hardware cloth at or near the inlet con-
nections. Make provisions to clean this screen of collected
debris after a few hours of operation. It should be removed
when its usefulness has ended, as the wire will eventually
deteriorate and small pieces going into the unit may cause
serious damage.
Pipe flanges or male threads must meet the unit connections
accurately and squarely. DO NOT attempt to correct misalign-
ment by springing or cramping the pipe. In most cases this
will distort the unit casing and cause impeller rubbing. In
severe cases it can prevent operation or result in a broken
drive shaft. For similar reasons, piping should be supported
near the unit to eliminate dead weight strains. Also, if pipe
expansion is likely to occur from temperature change, instal-
lation of flexible connectors or expansion joints is advisable.
Figure 3a, page 14, figure 3b, page 16, figure 3c, page 19 and
figures 3d, 3e, 3f and 3g, pages 23 and 24, represents an
installation with all accessory items that might be required
under various operating conditions. Inlet piping should be
completely free of valves or other restrictions. When a shut-
off valve can not be avoided, make sure a full size vacuum
relief is installed nearest the unit inlet. This will protect
against unit overload caused by accidental closing of the
shut-off valve.
Need for an inlet silencer will depend on unit speed and pres-
sure, as well as sound-level requirements in the general sur-
roundings. An inlet filter is recommended, especially in dusty
or sandy locations. A discharge silencer is also normally sug-
gested, even though Whispair units operate at generally lower
noise levels than conventional rotary blowers. Specific rec-
ommendations on silencing can be obtained from your local
Roots distributor.
Discharge piping requires a pressure relief valve, and should
include a manual unloading valve to permit starting the unit
under no-load conditions. Reliable pressure/vacuum gauges
and good thermometers at both inlet and discharge are rec-
ommended to allow making the important checks on unit
operating conditions. The back-pressure regulator shown in
Figure 3a, page 14 in the Gas Section, is useful mainly when
volume demands vary while the unit operates at constant out-
put. If demand is constant, but somewhat lower than the unit
output, excess may be blown off through the manual unload-
ing valve.
In multiple unit installations where two or more units oper-
ate with a common header, use of check valves is mandato-
ry. These should be of a direct acting or free swinging type,
with one valve located in each line between the unit and head-
er. Properly installed, they will protect against damage from
reverse rotation caused by air and material back-flow through
an idle unit.
After piping is completed, and before applying power, rotate
the drive shaft by hand again. If it does not move with uni-
form freedom, look for uneven mounting, piping strain,
excessive belt tension or coupling misalignment.
DO NOT operate the unit at this time unless it has been lubri-
cated per instructions.

9For your nearest Roots office contact information, please consult the last page of this document.
Blower Orientation Conversion - RAM WHISPAIR™ units

10
Recommended Oil Grades
400 - 600 RAM & RCS-V (air only), GAS, DVJ & VJ Blowers
Ambient* ISO
Temperature °F (°C) Viscosity No.
Above 90° (32°) 320
32° to 90° (0° to 32°) 220
0° to 32° (-18° to 0°) 150
Below 0° (-18°) 100
Use a good grade of industrial type non-detergent, rust
inhibiting, anti-foaming oil and of correct viscosity per the
above table. *Roots synthetic oil (Roots P/N 813-106-) is
specified and recommended. Roots does not recommend
automotive type lubricants, as they are not formulated with
the properties mentioned above.
Specific oil specifications apply for use in RAM/GAS blow-
ers. The specified oil should be Roots synthetic P/N 813-
106- of the proper viscosity.
RAM, RAM-J Approximate Oil Sump Capacities
Gearbox Drive End
Orientation Fl. Oz. (Liters) Fl. Oz. (Liters)
400 (Horizontal) 36 1.06 19 .56
400 (Vertical) 18 .52 9 .27
600 (Horizontal) 95 2.81 50 1.48
600 (Vertical) 55 1.63 28 0.83
RCS-V, RCS-JV Approximate Oil Sump Capacities
Gearbox Drive End
Orientation Fl. Oz. (Liters) Fl. Oz. (Liters)
400 (Vertical) 30 .089 18 0.53
600 (Vertical) 64 1.89 32 0.95
These capacities are provided to assist stocking the correct amount of oil. Exact sump capacity may
differ slightly. See “Lubrication” section for proper filling instructions.
Due to sludge build-up and seal leakage problems, Roots rec-
ommendation is DO NOT USE Mobil SHC synthetic oils in
Roots blowers.
Bearings and oil seals are lubricated by the action of the tim-
ing gears or oil slingers which dip into the main oil sumps
causing oil to splash directly on gears and into bearings and
seals. A drain port is provided below each bearing to prevent
an excessive amount of oil in the bearings. Seals located
inboard of the bearings in each headplate effectively retain oil
within the sumps. Any small leakage that may occur should
the seals wear passes into a cavity in each vented headplate
and is drained downward.
Oil sumps on each end of the blower are filled by removing
top vent plugs, Item (21), and filling until oil reaches the mid-
dle of the oil level sight gauge, Item (37).
Initial filling of the sumps should be accomplished with the
blower not operating, in order to obtain the correct oil level.
Approximate oil quantities required for blowers of the various
models and configurations are listed in the Oil Sump
Capacities table below. Use a good grade of industrial type
non-detergent, rust inhibiting, anti-foaming oil and of correct
viscosity per Recommended Oil Grades table on this page.
*Roots synthetic oil (Roots P/N 813-106-) is specified. Roots
does NOT recommend automotive type lubricants, as they are
not formulated with the properties mentioned above.
The oil level should not fall below the middle of the site gauge
when the blower is idle. It may rise or fall on the gauge dur-
ing operation, to an extent depending somewhat on oil tem-
perature and blower speed.
Proper lubrication is usually the most important single con-
sideration in obtaining maximum service life and satisfactory
operation from the unit. Unless operating conditions are
quite severe, a weekly check of oil level and necessary addi-
tion of lubricant should be sufficient. During the first week of
operation, check the oil levels in the oil sumps about once a
day, and watch for leaks. Replenish as necessary. Thereafter,
an occasional check should be sufficient. It is recommended that
the oil be changed after initial 100 hours of operation.
Frequent oil changing is not necessary unless the blower is
operated in a very dusty location.
Normal life expectancy of petroleum based oils is about 2000
hours with an oil temperature of about 180°F (82°C). As the
oil temperature increases by increments of 15-18°F (8°C -
10°C), the life is reduced by half. Example: Oil temperatures of
210-216°F (99°C - 102°C) will produce life expectancy of 1/4
or 500 hours. Therefore, it is considered normal to have oil
change periods of 500 hours with petroleum based oils.
Normal life expectancy of Roots Synthetic Oil is about 4000
to 8000 hours with an oil temperature of about 180°F (82°C).
As the oil temperature increases by increments of 15-18°F
(8°C - 10°C), the life is reduced by half. Example: Oil tempera-
tures of 210-216°F (99°C - 102°C) will produce life expectancy
of 1/4 or 1000 to 2000 hours.
NOTE: To estimate oil temperature, multiply the discharge
temperature of the blower by 0.80. Example: if the discharge
air temperature of the blower is 200° F, it is estimated that
the oil temperature is 160° F.
*Roots Synthetic Oil is superior in performance to petroleum based products. It has
high oxidation stability, excellent corrosion protection, extremely high film strength and
low coefficient of friction. Typical oil change intervals are increased 2-3 times over
petroleum based lubricants. Also, Roots Synthetic Oil is 100% compatible with petrole-
um based oils. Simply drain the oil in the blower and refill the reservoirs with Roots
Synthetic Oil to maintain optimum performance of your ROOTS blower.
Lubrication
*Ambient temperature is defined as the temperature of the space in
which the blower and drive are located.

11For your nearest Roots office contact information, please consult the last page of this document.
Inspection & Maintenance: RAM & RCS (400 & 600 RCS vertical only) Series - GAS, DVJ, DPJ & VJ
A good program of consistent inspection and maintenance is
the most reliable method of minimizing repairs to a blower. A
simple record of services and dates will help keep this work
on a regular schedule. Basic service needs are:
• Lubrication
• Checking for hot spots
• Checking for increases or changes in vibration and noise
• Recording of operating pressures and temperatures
Above all, a blower must be operated within its specified rat-
ing limits, to obtain satisfactory service life.
A newly installed blower should be checked often during
the first month of full-time operation. Attention there after
may be less frequent assuming satisfactory performance.
Lubrication is normally the most important consideration
and weekly checks of lubricant levels in the gearbox and
bearing reservoirs should be customary. Complete oil
change schedules are discussed under LUBRICATION.
Driver lubrication practices should be in accordance with the
manufacturer’s instructions. If direct connected to the blower
through a lubricated type coupling, the coupling should be
checked and greased each time blower oil is changed. This
will help reduce wear and prevent unnecessary vibration. In
a belted drive system, check belt tension periodically and
inspect for frayed or cracked belts.
In a new, and properly installed, unit there is no contact
between the two impellers, or between the impellers and
cylinder or headplates. Wear is confined to the bearings
(which support and locate the shafts) the oil seals, and the
timing gears. All are lubricated and wear should be minimal
if clean oil of the correct grade is always used. Seals are
subject to deterioration and wear, and may require replace-
ment at varying periods.
Piston ring seals (28) are designed to operate without rub-
bing contact, once temperature and thermal growth have sta-
bilized. The stationary rings will rub the rotating sleeve (38)
briefly as a result of temperature cycles that occur during the
startup and shutdown of the unit. The sleeves are hardened
and the rings are coated with dry lubricant that provides for
temporary break in wear. Replace piston ring seals if they
become excessively worn.
Shaft bearings are designed for optimum life under average
conditions with proper lubrication and are critical to the serv-
ice life of the blower. Gradual bearing wear may allow a
shaft position to change slightly, until rubbing develops
between impeller and casing. This will cause spot heating,
which can be detected by observing these surfaces. Sudden
bearing failure is usually more serious. Since the shaft and
impeller are no longer supported and properly located, exten-
sive general damage to the blower casing and gears is likely
to occur.
Oil seals should be considered expendable items, to be
replaced whenever drainage from the headplate vent cavity
becomes excessive or when the blower is disassembled for
any reason. Some oil seal leakage may occur since an oil
film under the lip is required for proper operation.
Periodically leaked oil should be wiped off from surfaces.
Minor seal leakage should not be considered as indicating
seal replacement.
Timing gear wear, when correct lubrication is maintained,
should be negligible. Gear teeth are cut to provide the cor-
rect amount of backlash, and gears correctly mounted on the
shafts will accommodate a normal amount of tooth wear
without permitting contact between lobes of the two
impellers. However, too high an oil level will cause churning
and excessive heating. This is indicated by unusually high
temperature at the bottom of the gear housing. Consequent
heating of the gears will result in loss of tooth-clearance ,
backlash and rapid wear of the gear teeth usually will devel-
op. Continuation of this tooth wear will eventually produce
impeller contacts (knocking), and from this point serious
damage will be unavoidable if blower operation is continued.
A similar situation can be produced suddenly by gear tooth
fracture, which is usually brought on by sustained overload-
ing or momentary shock loads.
Problems may also develop from causes other than internal
parts failure. Operating clearances within a blower are only a
few thousandths of an inch. This makes it possible for
impeller interferences or casing rubs to result from shifts in
the blower mounting, or from changes in piping support. If
this type of trouble is experienced, and the blower is found
to be clean, try removing mounting strains. Loosen blower
mounting bolts and reset the leveling and drive alignment.
Then tighten mounting again, and make sure that all piping
meets blower connections accurately and squarely. Foreign
materials sucked into the blower will also cause trouble,
which can only be cured by disconnecting the piping and
thoroughly cleaning the blower interior.
A wide range of causes & solutions for operating troubles
are covered in the TROUBLESHOOTING CHECKLIST. (See
specific sections for each series of blowers). The remedies
suggested should be performed by qualified mechanics with
a good background. Major repairs generally are to be con-
sidered beyond the scope of maintenance, and should be
referred to an authorized Roots distributor.
Warranty failures should not be repaired at all, unless specif-
ic approval has been obtained through a Sales Office or the
factory before starting work. Unauthorized disassembly
within the warranty period may void the warranty.

12
Troubleshooting Checklist (See each section for more specific information)
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
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
Damage to bearings 12 Inadequate lubrication Check oil sump levels in gear and drive end headplates
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
Excessive oil leakage 29 Defective/plugged breather Replace breather and monitor oil leakage
in vent area 30 Oil level too high Check sump levels in gear and drive headplates.
31 Oil type or Check oil to insure it meets recommendations. Drain then
viscosity incorrect fill with clean oil of recommended grade.
32 Blower running hot Check blower operating conditions to ensure they are within
the operating limitations defined in this manual.

13For your nearest Roots office contact information, please consult the last page of this document.
GAS Blowers
WHISPAIR™Gas Blower
WHISPAIR Gas Blower units are the same general design as
the standard WHISPAIR model except that (4) mechanical
seals are used in place of the (4) inboard lip seals. The seal
chambers are piped to plugged connections. These should
be opened periodically to confirm that there is no build-up of
oil due to leakage by the mechanical seal. Special traps may
be required for vacuum operation. These units are intended
for use with all gases which are compatible with cast iron,
ductile iron, viton o-rings, 300 & 400 series stainless steel
and carbon components of the mechanical seals. If there are
any questions as to suitability of materials, consult the Roots
sales office.
Precaution: WHISPAIR Gas Blower
The mechanical seals may leak some amount of the process
gas to the atmosphere through the gear/box end cover
breather caps. If this leakage is undesirable, for toxic/haz-
ardous gases, provide inert purge gas in the vent chamber
between the mechanical seals and the piston ring seals, refer
to Figure 1a. The purge gas pressure in the vent chamber
should be maintained at about 1 psi over the discharge pres-
sure.
The plugged drain connections are provided to allow periodic
draining of any fluid which might accumulate in the seal
chamber. This can be a combination of lubricating oils, liq-
uids entrained in the process gas, or condensables from the
process gas. Care must be used when opening the vent
drain plugs as some gas will also escape if it is a pressure
system. For system under vacuum the air will leak in. Never
vent explosive or toxic gases in an unsafe manner. Care
must be used when opening oil fill and oil drain plugs. The
gas leakage past mechanical seal could accumulate in the
gear box and drive end cover oil sump areas and leak out to
the atmosphere. If there is any question regarding applica-
tion or operation of this gas pump consult the Roots sales
office.
Conversely, if the system is under vacuum, there will be leak-
age of atmospheric air into the system through the breather
and the lube chamber, and by the mechanical seals or from
vent drain when plug is open. This gas will contain oil vapor.
If the process gas is non-toxic/non-hazardous and the leaked
gas needs to be piped away, refer to Figure 1a for piping
arrangement. The piping arrangement should not cause back
pressure in excess of 10” water column.
Figure 1a

14
Figure 3a Gas Blower Installation with Accessories
Above are suggested locations for available accessories.
404 4.5 4000 240 (133) 18 (1241) 16 (539)
406 4.5 4000 240 (133) 18 (1241) 16 (539)
409 4.5 4000 240 (133) 18 (1241) 16 (539)
412 4.5 4000 240 (133) 15 (1034) 16 (539)
418 4.5 4000 240 (133) 10 (690) 16 (539)
616 6.0 3000 230 (128) 15 (1034) 16 (539)
624 6.0 3000 230 (128) 10 (690) 16 (539)
Table 1a RAM-G & RAM-GJ Blower Maximum Allowable Operating Conditions
Frame Gear Speed Temp. Rise Delta Pressure Inlet Vacuum
Size Diameter (Inch) RPM F° (C°) PSI (mbar) INHG (mbar)

15For your nearest Roots office contact information, please consult the last page of this document.
400 - 600 Series DVJ Blowers
10
8
6
4
2
0
2600 3000 3400 4200 4600 5000 5400
Discharge Back Pressure Limits
Gear Speed-Ft./Min.
Discharge Pressure Inches H2O
406 4000 275 (153) 27 684
412 4000 300 (167) 27 684
616 3000 300 (167) 27 684
Table 1b RAM-DVJ blower
Maximum Allowable Operating Conditions
Frame Speed Temp. Rise Inlet Vacuum
Size RPM F° (C°) INHG (mbar)
Troubleshooting
All troubleshooting points in this manual should be followed
with the addition/or supersedure of the following:
Excessive temperature rise - check for possible cylinder slot
inlet flow restriction, excessive backpressure on the dis-
charge, and trouble shooting checklist in the appropriate
instruction and operation manual.
NOTES:
No valves should be installed in the discharge
or jet silencer pipe.
Jet silencer should be a chamber type (non-packed).
Information in this section not to conflict with ohter sections
of this manual.
Operating Limitations
Normal DVJ applications have a vacuum on the inlet and
atmospheric pressure on the discharge jet port connections.
Any unnecessary restrictions of dischargeflow or atmospher-
ic air inlet to the jet port reduces the cooling air flow and lim-
its blower operation, as the maximum temperature rise will
occur below the normal limits of vacuum level.
NOTE: One jet port must have a full size inlet silencer with no
valve or other restrictions. The other port must have the
metal cover plate installed.
Installation
A temporary cover is installed on one jet port and a perma-
nent cover on the other at the factory. A silencer must be
installed in place of the temporary cover before operating the
blower, howevr, the permanent cover and silencer locations
may be exchanged if the installation requires.
The permanent cover must be removed, both jet plenums
inspected and cleared of foreign material, then the perma-
nent cover and silencer installed in the desired locations
before operating. Full size jet and discharge silencers are
desirable, however, the jet silencer may be reduced one nom-
inal size providing either the vacuum level is less than 18.5”
Hg or the gear speed is below 3650 feet per minute. Both the
jet silencer and the discharge silencer may be reduced one
nominal size in applications with vacuum levels less than
18.5” Hg and a gear speed below 3650 feet per minute.
Jet and discharge flow restrictions result in increased blower
temperature rise and should be checked as a possible cause
if the temperature rise limits blower operation to less than
the maximum vacuum level. Backpressure limits are shown
in Table 1 of this section. No valves should be used in the
discharge piping or jet silencer piping.
Some type of protection, such as a filter or screen
(1/4” mesh) is necessary to stop foreign particle entry
through the jet port. Outside installations may also require
some weather protection to prevent the entry
of rain or snow. An elbow or some other pipe configuration
is desirable to assist in keeping the screen clear of foreign
particles and the direct entry of rain or snow.
Operation
All check points should be followed with the addition and/or
superseded by the following:
(1, add.) Be carefull no rags, bolts, or dirt have
been left in the cylinder slot inlet plenums
(2, add.) No valves should be installed in the
discharge pipe or jet silencer pipe
The blower is suitable for vacuum operation only. A water
manometer should be used on the discharge plenum to
determine that the maximum discharge pressure has not
been exceeded.
Gear Speed = 0.262 x 4.5 x rpm for 400 Series
Gear Speed = 0.262 x 6.0 x rpm for 600 Series

16
Figures 3b - DVJ
VACUUM SYSTEM SCHEMATIC
For DVJ Applications

17For your nearest Roots office contact information, please consult the last page of this document.
Coating
The coating is basically a fine-grained natural graphite*. It is
applied as several coats. Coating applied after the
machine’s internal clearances and impeller timing are estab-
lished. The effect of coating is to close up internal clear-
ances, decreasing slip and increasing flow and efficiency at
any given speed. Exhaust air may carry some coating parti-
cles.
Characteristics of Machines with Coated Internal
Service
Machines with internal abradable coating are for use with
clean, dry air only.
After coating, it is not practical to try to measure clearances
involving these surfaces before or after running the machine.
After coating and before running, some coated surfaces may
even be touching. After running, the coated surfaces may
have abraded areas and scratches, due to run-in contact
between the surfaces.
Do not attempt to measure clearances involving coated sur-
faces as a basis for setting impellers in relation to the cylin-
der bore, headplates, or each other (fronts and backs).
Clearance settings can be made accurately only with uncoat-
ed parts.
Cleaning and Preservation
Where internal, inspection indicates a need for cleaning coat-
ed surfaces of dirt, dust, etc., wipe clean only with a clean,
dry rag. Do not use a solvent or cleaner of any kind or allow
a solvent or cleaner to reach these surfaces while cleaning
uncoated surfaces.
If internal protection from rust or corrosion is required due,
for example, to removal of the machine from service, or if
the internal protections furnished as shipped by the factory
has been removed, do not use a liquid preservative of any
kind on these coated surfaces. Bags of vapor inhibitor pow-
der, such as Shell Oil Company VPI No. 250 may be used
internally, with all machine openings sealed with vapor barri-
er paper or tape.
Trouble Shooting Check List
This list in standard instructions applies, except note that in
those lists and in various locations throughout the standard
instruction manuals for uncoated machines, rubbing, knock-
ing, contact and wear between internal surfaces are men-
tioned as trouble indicators. This is with respect to metal-to-
metal interference. Coated surfaces can have very close
clearances and will wear in, or abrade, between surfaces,
showing rub or scratch marks which are normal conditions.
These can usually be differentiated from metal-to-metal con-
tact.
Cleaning, Coating & Curing Procedures for
Applying Abradable Coating
General. These procedures are for coating new uncoated
repair parts, spot repair of coating, or renewal. If setting
clearances and timing are involved, this should be done
before the new parts are coated. Subsequent cleaning and
coating may involve at least partial disassembly for proper
cleaning without damaging the coating of other original parts
still coated, and to apply coating properly.
Normally, for new uncoated surfaces, three coats are applied
and each coat must be properly cured.
Cleaning Before Coating
For new uncoated surfaces, apply the cleaner with a clean,
“soaked” rag. Apply the cleaner liberally, allow to set for one
to two minutes, then wipe off. Repeat if necessary. Avoid
cleaning surfaces which will not be coated.
Wiping off with a clean, dry rag is the only cleaning allowable
for spot repair or renewal of existing coating except in the
case of a small area of grease or similar substance where
scraping clean before reaching bare metal may be attempted.
If too dirty to clean by these methods, disassembly will be
required to remove the coating entirely, solvent clean, and
recoat.
Preparation of Coating Material
The graphite suspended in the material settles out in a fairly
short time and the can must be shaken well, and also fre-
quently, during spray application. Generally, the initial shak-
ing should continue until the ball in the can rattles freely and
should then continue for at least five minutes more.
Coating General
Procedures for application are for one coat, but when multi-
ple coats are to be applied, EACH coat must be completely
cured per CURE procedure described following, before apply-
ing the next coat.
Coating Application
See notes on can concerning ventilation and inflammability.
Each layer of coating should be applied as evenly as possi-
ble. Note directions on the curing of each coating layer
applied before applying subsequent coats.
The best distance of spray can nozzle to surface being coated
is 8” to 12”. Try to maintain this distance wherever space
conditions allow it.
Coating Cure
This procedure is for EACH coat. When multiple coats are to
be applied, this curing procedure must be used on EACH
coat before the next coat is applied. Keep coated parts clean
during curing.
Note that coated parts may feel dry or “tack free” after a few
minutes, but the coat will not have the CURE that is required.
Curing Procedures
Alternate #1
Let set for 1-1/2 hours, minimum, at normal room tempera-
ture (not less than 70°F).
DVJ & DPJ Blowers are Supplied with Internal Abradable Graphite-Based Coating
*Abradable coating applied to impellers is Slip Plate #3 as manufactured by Superior Graphite Co. For a material safety
data sheet, go to www.slipplate.com. Study material safety data sheet before working with Slip Plate #3.

18
Alternate #2
Where ambient, and coated metal temperatures, are not at
least 70°F, allow each coat to cure at least overnight in shop
ambient (not warehouse or outdoors).
Alternate #3
Cure in oven, or by other source of even heat (not flame), for
10 minutes, minimum, at a temperature of 310°F ±10.
Alternate #4
Cure in oven, or by other source of even heat (not flame), for
one-half hour, minimum, at a temperature of 200°F ±10°.
Check for Rotation
Finish blower buildup if not completely assembled when coat-
ed. In some instances, it is possible that clearances will be
closed by coating to the extent that some surfaces touch.
This is all right because the coating will wear (abrade) off as
required. However, the blower may be hard to turn initially as
a result. Turn over by hand until the running is free. Do not
try to free up the blower by coupled or belted drive, and do
not try to spin the rotors with shop air. Do not attempt to
use any kind of solvent or cleaner to partially remove, coating
– as this could ruin all of the coating. If necessary, coating
can be scraped for such partial removal.
Complete Removal of Coating
This is for complete removal (to bare metal) of coating and
may require some blower disassembly (depending on blower
size and accessibility) for access to the coated parts and any
overspray. Apply removal fluid liberally with a clean,
“soaked” rag. Vigorously rubbing with this rag and scraping
of the softened coating is required to clean surfaces down to
bare metal, the amount of effort required will vary, depending
upon the solvent used. Some are more effective than others.
Protect surfaces, not coated, from rust.

19For your nearest Roots office contact information, please consult the last page of this document.
Information in this section should not conflict with other sec-
tions of this manual.
Operating Limitations
The RAM DPJ can be used in vacuum/pressure or combina-
tion applications as long as a portion of the discharge air is
recirculated through a pipe, with diameter equal to the return
air plenum port, and cooled before entering the return air
plenum. The recycled and cooled discharge air should be
above the dewpoint, which is approximately 110°F (43° C)
for 30 psi, and have a minimum pressure drop before enter-
ing the return air plenum. The maximum pressure drop
should not exceed the values given in Table 1c. The blower
inlet temperature, jet inlet temperature, inlet pressure, speed
and pressure rise are all factors which affect the temperature
rise. Therefore, a discharge air temperature switch, and ther-
mometers at blower discharge and jet inet, as shown on
Figure 2, are recommended. Roots recommends delta/differ-
ential pressure and temperature protection.
Installation
Inspect the return air plenum to be sure it is clear of any for-
eign material before installing the return cooled air piping
(full port size piping must be used). Inspect the cooler for
foreign material before installation, as dirt, metal shavings,
paper and other materials could restrict air flow to the blower
jets or damage close clearance rotating parts within the
blower.
Operation
NOTE: be sure the pressure drop between the blower dis-
charge and the return air inlet does not exceed the maximum
listed in Table 1c of this section.
Troubleshooting for DPJ Blowers
Trouble Item Possible Cause Remedy
High Temperature 1 Excessive pressure Check inlet pressure and discharge pressure and compare
rise across blower with Table 1 (DPJ)
2 Restriction in cooling Check P from discharge to jet inlet. Check piping, valves
air system and cooler to assure an open flow path.
3 Loss of coolant to Check coolant flow and temperature at inlet and
the jet cooler discharge of cooler
Frame
Size
406
Min.
1750
Max.
3820
Speed (RPM)
PSI
30
KPa
208
Pressure
P Across Blower
IN Hg
22
mm Hg
560
Vacuum
F°
275
C°
153
Temperature
Rise
PSI
0.73
IN Hg
1.5
Pressure Drop to Jet
mm Hg
38
Table 1c DPJ Blowers Maximum Allowable Operating Conditions
Figure 3c Flow Schematic for DPJ Applications
406 RAM DPJ Section
All troubleshooting points in this manual should be followed with the addition/or supersedure of the following:

20
Operating VJ Blowers 400 - 600 Series
Before operating a blower under power for the first time,
recheck the unit and the installation thoroughly to reduce the
likelihood of avoidable troubles. Use the following procedure
list as a guide, but consider any other special conditions in
the installation.
JBe certain that no bolts, tools, rags, or debris have
been left in the blower air chamber and piping.
JIf an outdoor intake without filter is used, be sure
the opening is located so it cannot pick up dirt and
is protected by a strong screen or grille. Use of the
VJ Section
ROOTS VJ vacuum blowers are designed to handle a limited
quantity of liquid without damage. This permits introduction
of sealing water at the blower inlet to improve operating effi-
ciency and reduce internal temperature rise. Part or all of the
water required fro sealing purposes may be present in the
process being served by the blower. If this water input rate is
known in terms of gallons per minute, and is less than the
Recommended Continuous Rate shown in Table 1d in this
section, spray injection of water may be reduced accordingly.
As a safety precaution, it is recommended that at least a
small quantity of water always be injected regardless of nor-
mal process water. This will reduce the likelihood of running
dry at some vacuum level that will cause damage.
Where liquid flow rates from a process are in excess of the
Recommended Continuous Rate in Table 1d in this section,
some method of water removal should be employed. this can
be a drain leg in the blower inlet piping, or a receiver and
water pump arrangement. On wet vacuum filter service a
vacuum receiver with filtrate removal system is recommend-
ed. This will normally serve the purpose of extracting excess
water without the addition of a separate moisture trap.
Should water input rates exceed recommended values in
Table 1d in this VJ Section, blower operation will become
noisy and rough. If continued for an extended period of time,
mechanical damage to the blower may result. Such high
rates will put too much water in the blower, and this will
increase horse power requirements to a point where the driv-
er may become overloaded.
A VJ vacuum blower should not be expected to handle solid
particles entrained in the sealing water on any continuous
basis. If material build-up on the surfaces of the impellers
and cylinder occurs, it must be removed to avoid internal
contacts and resultant damage. Suggested methods for pre-
venting scale build-up are outlined under OPERATION.
NOTE: If a VJ blower is to be converted from water sealed
operation to use as a dry vacuum blower, all scale or dirt
deposits must first be completely removed from all internal
surfaces.
Operating Limitations
To establish and maintain continued satisfactory perform-
ance, a ROOTS VJ vacuum blower must be operated within
certain approved limiting conditions. The Manufacturer’s
warranty is contingent on such operation.
Maximum limits for vacuum. temperature and speed, along
with recommended and maximum water flow rates as speci-
fied in Table 1d in this section, for various standard sizes of
single stage VJ blowers. These limits apply to all blowers of
normal construction and having normal internal operating
clearances when operating under standard atmospheric con-
ditions (inlet air at 68° F, discharge pressure at 14.7 PSIA).
Do not exceed any one of these limits.
Example: assuming water sealed operation the temperature
rise probably will be considerably below the allowable maxi-
mum. If the blower operating speed is also below the maxi-
mum, the inlet vacuum then becomes the limiting factor to
be watched. in other words, the operating limit is always to
be determined by the maximum rating reached first. It can be
vacuum pressure, speed, or temperature.
Temperature rise - normally this is not a problem in a wet
vacuum blower since the water used for sealing purposed
also removes the heat of compression. However, the VJ
blowers may be operated with the maximum temperature
rises listed in Table 1d in this section providing speed and
inlet vacuum limits are not exceeded.
Vacuum - with the blower discharge connected directly to
atmospheric pressure the suction or vacuum load on the
pump inlet as measured in inches of mercury (hg.) must not
be greater than the value listed for any specific frame size.
Speed Range - VJ vacuum blower may be operated at
speeds up to the maximum listed for each gear diameter or
frame series. They may be direct coupled to suitable con-
stant speed drivers, or belt driven to obtain intermediate
speeds.
Table 1d - VJ maximum Allowable Operating Conditions
*Applies to single stage VJ units as listed. The maximum inlet vacuum for two-stage VJ-2 combinations is 27 inches HG. based on 30” HgA.
barometer. The minimum level at which reliable vacuum performance can be calculated is 3” Hg. above the absolute saturation pressure of
the sealing water.
** Includes injected and process water. Total GPM is for either single stage or two-stage operation.
Frame
Size
406
409
412
418
616
624
IN Hg
24
24
24
20
24
20
mm Hg
610
610
610
508
610
508
Speed
(RPM)
F°
200
200
200
200
200
200
C°
94
94
94
94
94
94
3200
3200
3200
3200
2400
2400
GPM
4-1/2
4-1/2
4-1/2
4-1/2
6
6
Liters/Min
17
17
17
17
23
23
Recommended
Inlet
Vacuum*
Discharge
Temperature
Sealing Water Flow Rate Rate MAX**