Below is a troubleshooting guide describing potential root causes of this problem.

Steam to Gasket Bleed Valve
If the gasket bleed valve (needle valve) is open too far, a door gasket error can result.
The bleed valve is set at the factory at ¼ turn open and this setting should be
maintained in the field.

In some instances, if the valve packing gland becomes loose, the valve can open
greater than ¼ turn due to normal sterilizer vibrations. This can be prevented by
periodically checking the packing gland and tightening it if necessary.

Worn or Damage Gasket
If the gasket becomes excessively worn or damaged, steam or air can leak into the
chamber of to the outside of the door.

Particulate carryover in the steam or air supply can also prevent a complete gasket
seal. If this is suspected, then clean the gasket and the head ring groove.

Low Steam or Air Pressure
The air pressure should be set at 30 psi for air-to-gasket steam sterilizers and 35 – 40
psi for steam-to-gasket sterilizers.

Defective Gasket Pressure Switch
If the sterilizer will not start upon pressing the Start button and gives a gasket alarm
shortly thereafter, the root cause problem is likely the pressure switch. If the switch is
simply worn out, 95%+ of the time it will fail in the “open” position.

Adjustable Gasket Pressure Switch (Older Models)
If an errant adjustment to the switch is made in the field, it can be set too high and the
switch will never see the required pressure to “make” the switch and a gasket alarm will

Need assistance? Contact the PRIMUS service department at 877.679.7800 – Dave Schall.

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