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

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