Howden Roots Metric Series, Installation, Operation And Maintenance Manual

ISRB_2002 GEA 19171 Roots URAI 

Page 4 of 32

Installation 

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 and 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. 



  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 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 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 concrete pad, but this 

generally produces the least satisfactory results. It 

definitely causes the most problems in levelling 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 levelled steel or cast iron 

mounting plate be provided. The plate should be at least 

1 inch (25 mm) thick, with its top surface machined flat, 

and large enough to provide levelling 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. 

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