Howden Roots 2500 Series WHISPAIR MAX, Installation, Operation And Maintenance Manual

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