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

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