DO NOT take a blower apart. Most mechanics do not have the specialty tools required to take the unit apart without causing further damage. It is a rare event for a local shop to have the special tools required, the very close proprietary tolerances, and training required to successfully take a blower apart, rebuild it, and successfully return the unit to service.
The oil should be changed every 6,000 hrs. if using Roots synthetic oil, 3,000 hrs. if using other synthetic oils, and 2,000 hrs. if using hydrocarbon based oils if the oil operating temperature is 180°F. The oil life is reduced by one-half for every 15°F increment above 180° F.
ISO-220 at 32-90°F ambient temperature (or) intermittent operation. ISO-320 gear oil above 90°F (or) continuous operation. A Universal Series RAI requires Shell Gadus NLGI #2 premium grade aluminum complex grease on the drive shaft end.
If the unit does not have a sight glass, fill until oil shows in the overflow port. If the unit has oil sight glasses, fill to the middle of the sight glass. DO NOT overfill and remove excess oil if required.
After the first 100 hours of operation. Then in low dust environments, every 3-6 months and in high dust environments, every 1-3 months. An air intake filter gauge showing a maximum of 5-7” water gauge would indicate when to change the cartridge.
At a minimum, use a spring tension meter and tension the belts to the belt drive manufacturer’s design report values for properly tensioned belts. If using today’s self-tensioning belts (or) banded belts, use a sonic tension meter and tension the belts to the belt drive manufacturer’s design report values
It is not uncommon for a unit achieving 10 PSIG (or) greater discharge pressure to run at 250°F in summer. However, high temperature can indicate lack of lubrication, a partially closed inlet valve, a dirty filter cartridge(s), a partially closed discharge valve, (or) improper belt tension.
Shut the unit down. Inspect to ensure the inlet filter is clean, the inlet valve is open, the discharge valve is open, and there is no process material in the blower. If the inspection indicates everything appears okay, then restart the unit. If knocking (or) metallic rubbing continues, return the unit to a Factory Authorized Service Center for inspection and rebuild.
Lock out and tag out the motor. Disconnect the piping connections and remove the residual material if possible. Restart the system and check for unusual sounds (or) noise. If none are present, continue to run the unit normally. If the unit makes noise, take it out of service and return the unit to a Factory Authorized Service Center for inspection and rebuild.
Positive displacement blowers do not make pressure (or) vacuum. A PD blower is a constant flow, variable pressure device. So they merely use the available horsepower to work against the system which causes the pressure (or) vacuum pressure rise.
A Positive Displacement Blower requires the generated airflow to take away the heat of compression. So it can be slowed down within limits. Please contact your local Authorized Howden Roots Distributor (or) Authorized Service Center for assistance.