Diaphragm Type Dry Vacuum Pump｜Troubleshooting｜How to

Causes and solutions of failures and errors
　1. Problems with rotation and starting
　2. Abnormal Noises
　3. Pump performance degradation
Corrosion resistance of the diaphragm (synthetic rubber)
If the pump sucks the condensable gas that contains the moisture
Failures at vacuum starting
Differences between full load current value and starting current value

Causes and solutions of failures and errors

1. Problems with rotation and starting

Causes	Solutions
Power Failure	Repair
Power Switch Failure	Repair contact failure
Voltage Drop	Adjust the power supply voltage, and check the power supply cable
Disconnection of the cord	Replace or repair
Locked connecting rod	Disassemble pump head and check interior
The breaker has operated	Investigate the reasons for the operation
Problem with bearings	Replace or repair
Thermal protector has operated	Switch power OFF, and eliminate the cause of operation of the thermal protector
Low ambient temperature	Ensure that the temperature is 7～40℃
Vacuum starts inside the pump	Return the inside of the pump to atmospheric pressure

2. Abnormal Noises

Causes	Solutions
Damage to bearing	Replace or repair
Damage to diaphragm	Replace
Damage to motor	Replace or repair

3. Pump performance degradation

Causes	Solutions
Damage to diaphragm	Replace
Damage to inlet and outlet valves	Replace
Air filter clogging	Clean or replace
Leakage of the Intake pipe	Clean or replace
Voltage Drop	Adjust the voltage. Enhance the power line circuit
Ambient temperature is not appropriated	Ensure that the temperature is 7～40℃
Leakage from piping and connection parts	Inspect and repair pipe leaks

Corrosion resistance of the diaphragm (synthetic rubber)

Characteristics	NBR Nitrile rubber	FPM Fluorocarbon rubber	CR Chloroprene rubber	EPDM Ethylene・ Propylene rubber
Steam resistance	○	○	△	○
Ozone resistance	△	○	○	○
Halogen gas resistance	×	○	×	○
Concentrated nitric acid（61％）	×	△	×	×
Dilute nitric acid（12％）	×	○	×	○
Concentrated sulfuric acid（97％）	×	○	×	×
Dilute sulfuric acid（48％）	△	○	△	△
Concentrated hydrochloric acid	×	△	×	△
Concentrated phosphoric acid（85％）	×	○	△	○
Concentrated acetic acid (99％)	×	×	×	○
Dilute acetic acid（50％）	×	×	×	△
Ammonia gas (cold)	×	○	×	×
Benzene	×	△	×	×
Naphtha	×	△	×	×
Trichloroethylene	×	△	×	×
Methyl alcohol	○	×	○	○
Ethyl alcohol	△	△	○	○
Ethylene glycol	○	○	○	○
Acetone	×	×	×	○
Cresol	×	○	×	×

If the pump sucks the condensable gas that contains the moisture

Please remove the moisture. Otherwise, the life of the pump will be shortened.
Some components of the pump chamber are not water-resistant. If it is unavoidable to suck water vapor, it is more effective to operate the pump in an atmosphere open state frequently to let water inside out.

For example, even if components of the pump chamber is made of water-resistant fluorocarbon resin, it is effective to operate the pump after operations or several times a day in an atmosphere open state.

Failures at vacuum starting

When the pump stops due to an accident such as a power outage while operating at the ultimate pressure, the inside of the pump is kept vacuum.
Since a large differential pressure occurs between the vacuum state of inside and the atmospheric pressure state outside, it may be difficult to restart.
In such a situation, if the inside of the pump chamber is returned to atmospheric pressure ( vacuum break ), the pump will rotate smoothly.

If the pump is restarted without breaking the vacuum, it is difficult to start up

Overcurrent flows to the motor
The overcurrent causes the temperature of the pump to spike.
The pump may be damaged

Differences between full load current value and starting current value

Full load current value：The Input current value when the motor outputs at 100％. Also called the rated current value.
Starting current value：Current value when turning on the motor and starting operation.
It depends on the type of motor, but the current momentarily flows about 5 times the full load current value.

Diaphragm Type Dry Vacuum Pump