As an option, PRIMUS vertical door sterilizers can be provided with water-powered cylinders to raise and lower the chamber door(s). The following sizes are vertical door sterilizers:

  • AA 16×16
  • A 20×20
  • B 26×26

The cylinders are operated by two 3-way electric solenoids.

The door system uses two switches on the cylinder and one on the door head ring. The switches on the cylinder are lighted magnetic reed switches. The open door switch tells the controller that the door is fully opened. The door closed switch on the cylinder and on the head ring are wired in series and both have to be made in order for the operating technician to start a cycle.

Water pressure is controlled by a water regulator that is set in the range of 20 to 40 psig.

If the water pressure is set above 40 psig, an adjustable in-line check
valve will open and the water will flow to the drain instead of opening or
closing the door.


The speed of the door is controlled by a ¼-inch needle valve. This needle valve is located on the drain side of the solenoid valves.

There are three ways of operating the door on a single-door sterilizer:

  • The door button on the touchpad
  • A foot switch
  • A mushroom button located in the front fascia

On a double-door sterilizer, the foot switch and mushroom button
are not available. Only the door button on the touchpad is used.

To close the door, the operating technician is required to hold the foot switch, mushroom button, or door button until the door is fully closed.

To open the door, the operating technician is only required to push and release the button for the door to open.


Door Will Close on Its Own, but Needs Help to Open

This is usually caused by the magnet on the bottom of the door set too close to the strike plate. Loosen the magnet bracket and move the magnet away from the strike plate until it just comes in contact. The magnet is very strong and the door system has a hard time overcoming the pull force of the magnet if it is set too close to the strike plate.

Door Will Not Open or Close

Several things can cause this:

  • Regulator being set above 40 psig
  • Bleed valve closed or clogged
  • The in-line check valve is worn out

If the water pressure is set above 40 psig, the in-line check valve will open and not allow any water to the door cylinder.

The bleed valve should be opened enough to allow smooth movement of the door. It is also possible that the gauge on the water regulator is bad and not reading the actual water pressure. Use a secondary gauge to ensure the water regulator is set properly.

Vacuum Pump or Heat Exchanger Runs All the Time When the Door Is Open

This is caused by the door open switch being out of adjustment, switch failure, or the door is not fully open.

With the door all the way open, the light on the door open switch should be on. If it is not on, adjust the switch up and down until the light turns on. Check to make sure there are no obstructions preventing the door from opening all the way.

Door Stops and Starts While Opening or Closing

This is usually caused by the needle valve being out of adjustment or when the plumbing system has excessive water scale build-up in the internals of the valves, regulator, check valve, or bleed valve.

The valves and check valve should be taken apart and checked, cleaned, kitted, or replaced at every preventive maintenance period (PM).

All necessary PM parts are available in the PRIMUS parts warehouse and can be ordered on the SPIRE website or via phone or fax.

If the end user customer desires to remove the power door function, the software
will need to be replaced. Simply removing the mechanical system will cause the
controller to malfunction. New software can be ordered by contacting PRIMUS
Parts at 402-344-4200 Ext. 1010

Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.

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