How do I: Disable the vacuum pump?¶

XO-VAC+ is a Thermal Vacuum Chamber capable of operating in a wide range of temperatures (from -25C to 125C). If the main chamber is not under vacuum and the Thermal System is used, XO-VAC+ can get damaged. During a hot run, the main risk is to oxidize the shroud and compromising the radiation performance of the chamber. Cold runs are much more hazardous has water can condensed inside the chamber and create short circuits.

XO-VAC+ status¶

If you have doubts about the status of XO-VAC+ check the How to enable the Vacuum Pump? tutorial.

Disabling the vacuum pumps and venting the main chamber¶

Once it was determined that XO-VAC+ Vacuum Chamber can be safely vented to room temperature, press the on/off button (cicle with a vertical bar) on the right side of the Vacuum Control Panel.

The tubovacuum pump will start reducing its speed. It takes about 5 - 10 min for the turbo pump to go from full speed (1200 - 1500 Hz) to a speed low enough to start venting. The turbopump controller starts venting automatically when the turbopump speed is low enough for a safe venting.

During this operation, the pressure of the chamber will progressively increase to room temperature. To display the pressure in the Vacuum Chamber use the Left or the Right arrows until the code 340 is visible.

It takes about 10 - 15 min to vent a XO-VAC+ to room pressure.

Disabling the vacuum pumps without venting the main chamber¶

It is possible to power off the vacuum pumps without venting the main chamber.

By keeping the Vacuum Control box powered - Pressure readings available¶

It is the standard procedure for storing XO-VAC+ while not in use. Keeping the main chamber under vacuum when not in use to reduce possible contamination and maintain XO-VAC+ performance.

This can be also be useful in specific cases where the user wants to temporarily switch off the vacuum pumps to reduce the mechanical noise or EMI noise inside the vacuum chamber.

The first step is to change the behaviour of the venting valve. In normal operations (see above), the venting valve will automatically start venting when the turbovacuum speed is low enough. In this section, it is required for the venting valve to stay closed while the vacuum pump is powered off so that the chamber is not vented.

To change the venting valve behaviour:

1. use the Left or the Right arrows on the Vacuum Control Panel until the code 30 is visible
2. press on Left or the Right arrows simulatneously to be able to change the value associated to the code 30
3. use Left or the Right arrows to be able to change the value associated to the code 30
4. set the code 30 value to 1 to set the venting valve in No venting mode
5. press on Left or the Right arrows simulatneously to validate the value entered.

By powering off the Vacuum Control box - No pressure readings available¶

If the power is removed from the Vacuum Control Box:

• the roughening pump will immediately stop
• the turbopump will slowly start to decrease its speed
• the venting valve will stay close or close if a venting operation was in progress

The easiest way to do that is to flip the switch on the power entry connector at the back of the Thermal Control rackmount box.

The main downside of cutting the power to the Vacuum Control box is that pressure readings are not available anymore on the Vacuum Control Panel.