Troubleshooting

DANGER

Live wires.

Risk of electrical shock.

Electrical installation work must only be executed by qualified personnel.

CAUTION

Hot surface.

Risk of burns!

Before doing anything that requires touching the machine, let it cool down first.

Illustration showing parts that may be involved during troubleshooting:

Description
IS	Inlet screen	CPL	Coupling
GB	Gas ballast valve	EF	Exhaust filter
FV	Floating valve	OF	Oil filter

Problem	Possible Cause	Remedy
The machine does not start.	The motor is not supplied with the correct voltage.	Check the power supply.
	The motor is defective.	Replace the motor.
	The coupling (CPL) is defective.	Replace the coupling (CPL).
The machine does not reach the usual pressure on the suction connection.	Oil level too low.	Top up oil.
	The inlet screen (IS) is partially clogged.	Clean the inlet screen (IS).
	The inlet filter cartridge (optional) is partially clogged.	Replace the inlet filter cartridge.
	Internal parts are worn or damaged.	Repair the machine (contact Busch).
The machine runs very noisily.	Worn coupling (CPL).	Replace the coupling (CPL).
	Stuck vanes.	Repair the machine (contact Busch).
	Defective bearings.	Repair the machine (contact Busch).
The machine runs too hot.	Insufficient cooling.	Remove dust and dirt from the machine. Check the cooling fan.
	Ambient temperature too high.	Observe the permitted ambient temperature.
	Oil level too low.	Top up oil.
	The exhaust filters (EF) are partially clogged.	Replace the exhaust filters (EF).
The machine fumes or expels oil droplets through the gas discharge.	The exhaust filters (EF) are partially clogged.	Replace the exhaust filters (EF).
	An exhaust filter (EF) with o-ring is not fitted properly.	Ensure the correct position of the exhaust filters (EF) and the o-rings.
	The float valve (FV) does not work properly.	Check the float valve and the oil pipe for clogging. Remove the clogging.
	Version with oil return valve: The machine runs for more than 2 hours without interruption.	Regularly shut down the machine for short periods of time (see Version with Oil Return Valve).
Abnormal oil consumption.	Oil leaks.	Replace seals (contact Busch).
	The float valve (FV) does not work properly.	Check float valve and the oil return line, repair it if necessary (contact Busch).
	The machine runs at atmospheric pressure for a long period.	Make sure that the machine operates under vacuum.
The oil is black.	Oil change intervals are too long.	Flush the machine (contact Busch).
	The inlet filter (optional) is defective.	Replace the inlet filter.
	The machine runs too hot.	See problem "The machine runs too hot".
The oil is emulsified.	The machine sucked in liquids or significant amounts of vapor.	Flush the machine (contact Busch). Clean the filter of the gas ballast valve (GB). Modify the operational mode (see Conveying Condensable Vapors).

For resolution of problems not listed in the troubleshooting table, please contact your Busch representative.