What is going on during the cycle? What parts are working, and what are they supposed to do?

We know understanding the sequence of events will greatly assist you in troubleshooting, so here is some General Information on the System Operation - Use this guide to learn what is going on during the operation of your autoclave and determine where it is failing

With water level established, Door Tightened, (Model 8000DSE Slow Exhaust Switch OFF),timer selection made, and the power Switch ON, the autoclave will begin heating. The heating light will be lit, verifying that the heating circuit is operational.

While the chamber is heating to the desired sterilization level, cold air will be continuously purged from the system to provide uniform heat and steam pressure throughout the chamber.

A normally open solenoid valve provides venting of the Chamber until the Chamber atmosphere reaches a 3°C above the boiling point of water.

When the autoclave reaches this temperature (103°C) a temperature sensitive device will be activated. The sensor switch is normally open until this point, at which time the sensor switch will close and activate (close) the solenoid valve.

The chamber will begin to pressurize. Cold Air pockets (less than 103°C) will be forced to the bottom of the chamber.

The cold pockets of air will cool the sensor, and the sensor switch will open

In turn, the solenoid valve will open and the cold air will be vented from the chamber to the condensor tank

Once the cold air is eliminated, the sensor will detect the change in temperature.

Then the sensor switch will close, which activates (closes) the solenoid valve. Continuous purging of cold air will occur whenever the sensor is open

The temperature control is a pressure-sensitive switch. When the desired sterilizing temperature is reached, the normally closed temperature control switch will open according to the relationship that exists between the temperature and steam pressure

At this point, the temperature control switch will open the circuit to the heating element. The element will stop heating and the temperature indicator light will go off.

The temperature will drop. Correspondingly, the pressure will drop.

The temperature control is sensitive to a one pound drop in pressure. When it detects this one pound change, the temperature control switch will close. Electrical Current will be given a path to the heating element and the element will begin heating.

In this manner, the temperature control regulates the temperature inside the chamber. The temperature indicator light will verify the operation of the temperature control switch lighting up when the switch closes, and going out when the switch opens

The autoclaves are provided with two safety devices, a low water cutoff switch and a pressure relief valve. The Low Water Cutoff Switch will be activated if the unit is allowd to run out of water (caused by not filling to water indicator at the beginning of each cycle) or due to purge system failure in which the water is boiled out of the system

The normally closed (temperature sensitive) low water cutoff switch will open when it senses an outside chamber temperature of 149°C (Minimum) 232°C (maximum). It opens the heating crcuit, breacking the current path to the heating element

The Pressure Relief Valve is located in the condensor tank assembly. It is a safeguard against temperature control failure in which case the heating element would heat the chamber atmosphere beyond the limits of the temperature control.

Since increases in steam pressure are proportional to increases in temperature, the pressure relief valve will open when the chamber pressure approaches 35 psi (tolerances + 3 psi.

The valve will vent steam into the condenser tank. If no one is around to notice the malfunction, the relief valve will vent pressure from the chamber until the water is boiled out.

The low water cutoff switch will then shut the unit off as previously described.

Both the 9000D and 8000DSE are equipped with a dryer. With the Door ajar (3" to 4"), make a selection with the tempertaure-dryer switch, then dial the timer to the desired drying time

The temperature-dryer switch is a temperature sensitive swith. It regulates the temperature of the drying element by opening and closing the current path to the drying element

NOTE: Be sure the door remains ajar throughout the drying cycle