Howden Roots 2500 Series WHISPAIR MAX User manual

www.howden.com
Roots* 2500 Series WHISPAIR*
MAX Blowers and DVJ Blowers
Installation, Operation and Maintenance Manual
www.howden.com
Installation, Operation and Maintenance Manual
Roots* 2500 Series WHISPAIR*
MAX Blowers and DVJ Blowers
ISRB 2005 GEA 20260.indd 1 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 2 of 24
Contents
Information Summary .............................................2
Safety Precautions ..................................................3
Operating Limitations ..............................................3
Operation.................................................................4
Installation........................................................... 5-8
Lubrication .......................................................... 8-9
Inspection & Maintenance.....................................10
Troubleshooting ....................................................11
2500 WHISPAIR Max Section ...............................12
DVJ Section ...........................................................13
Internal Abradable Coating ....................................14
Parts List ................................................................16
Drawings............................................................17-18
Do these things to get the most from your Roots Blower
Check shipment for damage. If found, fi le claim
with carrier and notify Howden Roots.
Unpack shipment carefully, and check contents
against Packing List. Notify Howden Roots if a
shortage appears.
Store 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.
Read OPERATING LIMITATIONS and
INSTALLATION sections in this manual and plan
the complete installation.
Provide for adequate safeguards against
accidents to persons working on or near the
equipment during both installation and operation.
See SAFETY PRECAUTIONS.
Install all equipment correctly. Foundation design
must be adequate and piping carefully done. Use
recommended accessories for operating
protection.
Make sure both driving and driven equipment is
correctly lubricated before start-up. See
LUBRICATION.
In event of trouble during installation or
operation, do not attempt repairs of Howden
Roots furnished equipment. Notify Howden
Roots, giving all nameplate information plus an
outline of operating conditions and a description
of the trouble. Unauthorized attempts at
equipment repair may void Howden Roots
warranty.
Units 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. Howden Roots reserves the right
to make design or material changes without notice,
and without obligation to make similar changes on
equipment of prior manufacture.
ISRB 2005 GEA 20260.indd 2 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 3 of 24
Safety Precaution
It is important that all personnel observe safety
precautions to minimize the chances of injury. Among
many considerations, the following should be
particularly noted:
Blower casing and associated piping or
accessories may become hot enough to cause
major skin burns on contact.
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 protective 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, lifting, installing, operating and
maintaining the equipment.
Casing pressure must not exceed 25 PSI (1725
mbar) gauge. Do not pressurize vented cavities
from an external source, nor restrict the vents
without fi rst consulting Howden 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 exercise 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 2, page 9 for Whispair Max and
Table 3, page 9 in the 2500 Series DVJ Section, for
allowable speeds for various models & sizes of
blowers and exhausters. These limits apply to all
units of normal construction, when operated under
standard atmospheric conditions. 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 operating 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 rating of 25 psi
gauge (1725 mbar) should not be exceeded without
first consulting Howden Roots. Never should the
maximum allowable differential pressure be
exceeded.
On vacuum service, with the discharge to
atmospheric pressure, 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
temperature limitations can be maintained in service:
Measured temperature rise must not exceed
listed values 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).
ISRB 2005 GEA 20260.indd 3 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 4 of 24
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 drivers 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 maximum rating reached fi rst. It
can be any one of the three: Pressure, Temperature
or Speed.
Operation
Before operating a blower under power for the fi rst
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 conditions 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 protected 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
necessary 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 pressure. 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
ISRB 2005 GEA 20260.indd 4 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 5 of 24
CHECKLIST for suggestions on various problems
that may appear.
The blower should now be ready for continuous duty
operation 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, verify 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 unloading or vent
valve. Never rely on the pressure relief valve as an
automatic vent. Such use may cause the discharge
pressure to become excessive, and can also result in
unsafe operation of the valve itself. If blower capacity
appears to be too low, refer to the
TROUBLESHOOTING CHECKLIST. See page 11 for
additional troubleshooting information regarding DVJ
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 foundations.
In general, blower vibration levels should be
monitored on a regular basis and the vibration trend
observed for progressive 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 vibration levels and the action required.
Installation
Howden 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 corrosion protection. See “Cleaning
& Preservation” on page 14 for Whispair Max and
DVJ units.
Coat 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.
Paint shaft extension, inlet and discharge
flanges, and all other exposed surfaces with Nox-
Rust X-110 or equivalent.
Seal inlet, discharge, and vent openings. It is not
recommended that the unit be set in place, piped
to the system, 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.
Protect units from excessive vibration during
storage.
Rotate shaft three or four revolutions every two
weeks.
Prior 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
ISRB 2005 GEA 20260.indd 5 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 6 of 24
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 outdoor location will normally
give satisfactory service. Important requirements are
that the correct grade of lubricating oil be provided for
expected operating temperatures, and that the unit
be located so that routine checking and servicing can
be performed conveniently. Proper care in locating
driver and accessory equipment must also be
considered.
Supervision of the installation by a Howden Roots
Service Engineer is not usually required for these
units. Workmen with experience 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 compliance with
safe practices. Unit mounting must be solid, without
strain or twist, and air piping must be clean,
accurately 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 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 passing 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 a
petroleum 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 concrete 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, it is recommended that a
well anchored and carefully leveled steel or cast iron
mounting plate be provided. The plate should be at
least 1 inch (25 mm) thick, with its top surface
machined fl at, and large enough to provide leveling
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 mounting 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 is to be treated as a unit for
leveling purposes. Satisfactory installation can be
obtained by setting the baseplate on a concrete slab
that is rigid and free of vibration, and levelling the top
of the base carefully in two directions so that it is free
ISRB 2005 GEA 20260.indd 6 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 7 of 24
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 twisted 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 necessary corrections.
In planning the installation, and before setting the
unit, consider how piping arrangements are dictated
by the unit design and assembly. Drive shaft rotation
must be established accordingly and is indicated by
an arrow near the shaft.
When a unit is DIRECT COUPLED to its driver, the
driver RPM must be selected or governed so as not
to exceed the maximum speed rating of the unit.
Refer to Table 2, page 9 in the 2500 Series Whispair
Max Section, Table 3, page 9 in the DVJ 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 bearings. When a motor, engine
or blower is operated the shafts may expand axially.
If the coupling is installed in such a manner 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 damage 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
coupling are normally too large to achieve smooth
operation and maximum life of the blower.
The following requirements of a good installation are
recommended. When selecting a coupling to be fitted
to the blower shaft Howden 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 fi t. Coupling halves must be warmed up
per coupling manufacturer’s recommendations.
Maximum deviation in offset alignment of the shafts
should not exceed .005” (.13 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 selecting a sheave to be fitted to the
blower shaft Howden Roots recommends a taper lock
style sheave to insure proper contact with the blower
shaft. This flexibility can lead to operating
temperature 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 2, page 9 in the 2500 Series
Whispair Max Section, Table 3, page 9 in the DVJ
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 (horizontal piping) and on
the side nearest to the shaft on a horizontal unit. (See
page 7 for acceptable V belt drive configurations.)
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 distance known for the belt lengths to be
used.
CAUTION: Drive couplings and sheaves (pulleys)
should have an interference fi t to the shaft of the
blower (set screw types of attachment generally do
not provide reliable service.)
ISRB 2005 GEA 20260.indd 7 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 8 of 24
Allowable Overhung Loads for V-belt Drives for 2500 Series WHISPAIR MAX
and DVJ Blowers
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 3VX,
5VX or 8VX matched set or banded belts and
sheaves.
Acceptable Blower Drive Arrangement Options
ISRB 2005 GEA 20260.indd 8 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 9 of 24
When a unit is BELT DRIVEN, the proper selection of
sheave diameters will result in the required unit
speed. When selecting a sheave to be fitted to the
blower shaft ROOTS recommends a taper lock style
sheave to insure proper contact with the blower shaft.
This flexibility can lead to operating temperature
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 2, page 9 in the 2500 Series Whispair Max
Section, Table 3, page 9 in the DVJ 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 (horizontal piping)
and on the side nearest to the shaft on a
horizontal unit. (See page 7 for acceptable V belt
drive configurations.) 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 distance
known for the belt lengths to be used.
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 fi t
required. Drive couplings, that require heating to fi t
on the blower shaft, should be installed per coupling
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 consideration 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 fl y-wheel and/or a torsionally
soft elastic element coupling based on the Engine
manufacturer recommendations.
When a unit is DIRECT COUPLED to its driver, the
driver RPM must be selected or governed so as not
to exceed the maximum speed rating of the unit.
Refer to Table 1 for allowable speeds of various unit
sizes.
The driver sheave should also be mounted as close
to its bearing as possible, and again should fi t 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 minimizes
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 failures 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, and
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 connections. 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 misalignment 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
ISRB 2005 GEA 20260.indd 9 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 10 of 24
temperature change, installation of flexible
connectors or expansion joints is advisable.
Figure 1, page 12 for Whispair Max and Figure 2,
page 14 for DVJ blower 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 cannot 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 pressure, as well as sound-level requirements in
the general surroundings. An inlet filter is
recommended, especially in dusty or sandy locations.
A discharge silencer is also normally suggested,
even though Whispair units operate at generally
lower noise levels than conventional rotary blowers.
Specific recommendations on silencing can be
obtained from your local Howden 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 recommended to allow
making the important checks on unit operating
conditions.
In multiple unit installations where two or more units
operate with a common header, use of check valves
is mandatory. These should be of a direct acting or
free swinging type, with one valve located in each
line between the unit and header. 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 uniform 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 lubricated per instructions.
Lubrication
Due to sludge build-up and seal leakage problems,
Roots recommendation is DO NOT USE Mobil SHC
synthetic oils in Roots blowers.
2500 Series blowers gear end bearing lubrication.
The specified and recommended oil is Roots
Synthetic oil of correct viscosity per Table 1,
page 9.
To fill the gearbox, remove the oil fill plug (140)
and the oil level plug (111) - see page 8. Fill the
reservoir up to the overflow hole. DO NOT
OVERFILL. Place the breather and the overflow
plug back into their respective holes.
The lubrication should be changed after initial
100 hours of operation.
If you choose to use another oil other than the
specified and recommended Roots Synthetic,
use a good grade of industrial type non-
detergent, rust inhibiting, anti-foaming oil and of
correct viscosity per Table 1, page 9.
Roots does NOT recommend the use of
automotive type lubricants, as they are not
formulated with the properties mentioned above.
Proper service intervals of the oil thereafter are
based on the discharge air temperature of the
blower. Please refer to the information below to
“How to properly determine the oil service
intervals.”
How to properly determine the oil service
intervals:
Normal life expectancy of the specified and
recommended Roots Synthetic oil is approximately
6000 hours with an oil temperature of 180°F (82°C)
or less. As the oil temperature increases by
increments of 15°F (8°C), the oil life is reduced by
half for each 15°F (8°C) increase. Example: Oil
temperatures of 195°F (90.5°C) will produce a life
expectancy reduced by half or 3000 hours oil service
life.
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°F (8°C), the life is reduced by half
for each 15°F (8°C) increase. Example: Oil
temperatures of 195°F (90.5°C) will produce life
expectancy reduced by half or 1000 hours oil service
life.
ISRB 2005 GEA 20260.indd 10 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 11 of 24
The oil sump on the gear end of the blower is filled by
removing top plug Item (140), and filling until oil flows
from overflow plug, Item (111).
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
2500 Series blowers with grease lubricated drive end
bearings.
When servicing drive end bearings of use the
specified and recommended Shell Darina SD 2 NLGI
#2 product code 506762B.
For grease lubricated drive end blowers see Table 1,
page 9, regarding specified greasing intervals.
Lithium based greases are not compatible with the
specified and recommended Shell Darina SD 2
grease used when assembling the blower. Lithium
based grease is not approved for any Roots blowers.
Table 3, page 9 has been prepared as a general
greasing schedule guide based on average operating
conditions. More frequent intervals may be necessary
depending on the grease operating temperature and
unusual circumstances.
A simple but very effective lubrication system is
employed on the drive shaft end bearings. Hydraulic
pressure relief fittings are provided to vent any
excess grease, preventing pressure build-up on the
seals. A restriction plug and metering orifice prevent
loss of lubricant from initial surges in lubricant
pressure but permit venting excess lubricant under
steadily rising pressures.
Using a pressure gun, slowly force new lubricant into
each drive end bearing housing until traces of clean
grease comes out of the relief fitting. The use of an
electric or pneumatic grease gun could force the
grease in too rapidly and thus invert the seals and
should not be used.
Gear end bearings, gears and oil seals are lubricated
by the action of the timing gears 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.
Proper lubrication is usually the most important single
consideration in obtaining maximum service life and
satisfactory operation from the unit. Unless operating
conditions are severe, a weekly check of oil level and
necessary addition 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.
More frequent oil service may be necessary if the
blower is operated in a very dusty location.
*Roots Synthetic oil is superior in performance to
petroleum based products. It has high oxidation
stability, excellent corrosion protection, extremely
high fi lm 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 petroleum
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.
ISRB 2005 GEA 20260.indd 11 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 12 of 24
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.
Inspection & Maintenance: 2500 Series WHISPAIR Max and DVJ Blowers
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 rating limits, to obtain satisfactory service
life.
A newly installed blower should be checked often
during the first month of full-time operation. Attention
thereafter 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
ISRB 2005 GEA 20260.indd 12 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 13 of 24
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 replacement
at varying periods.
Shaft bearings are designed for optimum life under
average conditions with proper lubrication and are
critical to the service 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 situations is usually more serious. Since the
shaft and impeller are no longer supported and
properly located, extensive 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 weepage
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 weepage 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 correct 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 develop. 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 overloading or momentary shock loads.
Problems may also develop from causes other than
internal parts damage. 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. The remedies suggested should be
performed by qualified mechanics with a good
background. Major repairs generally are to be
considered beyond the scope of maintenance, and
should be referred to your local Roots blower
distributor.
Warranty situations should not be repaired at all,
unless specific approval has been obtained through a
Sales Office or the factory before starting work.
Unauthorized disassembly within the warranty period
may void the warranty.
ISRB 2005 GEA 20260.indd 13 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 14 of 24
Troubleshooting Checklist
ISRB 2005 GEA 20260.indd 14 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 15 of 24
2500 Series WHISPAIR Max Blowers
ISRB 2005 GEA 20260.indd 15 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 16 of 24
2500 Series DVJ Blowers
Information in this section not to conflict with other
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 discharge flow or
atmospheric air inlet to the jet port reduces the
cooling air flow and limits 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
permanent cover on the other at the factory. A
silencer must be installed in place of the temporary
cover before operating the blower, however, 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 permanent 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 nominal 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 5 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 careful 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.
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 discharge, and troubleshooting
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).
ISRB 2005 GEA 20260.indd 16 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 17 of 24
NOTE: One cylinder slot plenum must have a full size
inlet silencer with no valve or other restrictions. The
other port must have the 2” countersunk pipe plug
installed.
ISRB 2005 GEA 20260.indd 17 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 18 of 24
DVJ Blowers are supplied with Internal Abradable Graphite-Based Coating
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 established. The effect of coating
is to close up internal clearances, decreasing slip and
increasing flow and efficiency at any given speed.
Exhaust air may carry some coating particles.
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 surfaces as a basis for setting impellers in
relation to the cylinder bore, headplates, or each
other (fronts and backs).
Clearance settings can be made accurately only with
uncoated parts.
Cleaning and Preservation
Where internal, inspection indicates a need for
cleaning coated 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 powder, such as
Shell Oil Company VPI No. 250 may be used
internally, with all machine openings sealed with
vapor barrier 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, knocking, contact and wear
between internal surfaces are mentioned 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 contact.
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 frequently, during spray application.
Generally, the initial shaking should continue until the
ball in the can rattles freely and should then continue
for at least five minutes more.
ISRB 2005 GEA 20260.indd 18 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 19 of 24
Coating General
Procedures for application are for one coat, but when
multiple coats are to be applied, EACH coat must be
completely cured per CURE procedure described
following, before applying the next coat.
Coating Application
See notes on can concerning ventilation and
inflammability.
Each layer of coating should be applied as evenly as
possible. 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
temperature (not less than 70°F).
**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.
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 build up if not completely assembled
when coated. 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.
ISRB 2005 GEA 20260.indd 19 17/09/2015 12:53

ISRB 2005 GEA 20260 Page 20 of 24
ISRB 2005 GEA 20260.indd 20 17/09/2015 12:53