MVE Biological Systems
TEC 3000 Operating and Maintenance Freezer Manual
13289499 Rev H •
116
Level Alarm Test
The TEC 3000 control system can trigger a high level or low level alarm if the LN2 level in the
freezer exceeds the user defined parameters.
High Level Alarm Test:
1. Observe and record the current LN2 level
2.
Record the current level settings. They may be accessed by pressing the “▲” and “▼”
simultaneously to access the quick reference menu, or through the Liquid Level Menus.
The current LN2 level should be between the High Level Alarm setting and Low Level
Alarm setting. If not, allow the freezer to fill until it reaches the High Level Fill set point.
3. Adjust the level offset so that the current level is a value that is greater than the High Level
Alarm setting. For example, if the High Level Alarm setting is currently 10.0 inches,
increase the offset value by at least 1.0 inch. This will “fool” the controller into thinking that
the level inside the freezer is higher than actual. Reference section 7.2.2.3 page 54 for
level offset adjustment.
4. Observe the audible/visual alarm. Be aware that the level alarms have a one minute.
This delay is intentional and is to prevent nuisance alarms.
5. If the alarm does not occur after one minute, verify that the audible alarm is turned on
6. Decrease the offset value to the original observed setting.
Low Level Alarm Test (Stand Alone TEC 3000 configuration):
1. Observe and record the current LN2 level.
2. Remove the vinyl tube from the hose barb on the bottom of the TEC 3000. Be careful not
to damage the tube
3. The displayed level should drop to 0.0 inches.
4. After one minute, the audible alarm should sound
5. If the alarm does not sound, verify that the audible alarm is turned on.
6. Reconnect the vinyl tube. If the tube is deformed at the end, it may be necessary to trim off
¼” of the tube to ensure a good connection.
7.
Press “Fill Start” to purge the level sensing line. After 30 seconds, the level should
gradually increase to actual.
8. After the fill cycle is complete, manually measure the level using the dipstick
Low Level Alarm Test (Cabinet model freezers):
1. Observe and record the current LN2 Level
2. Adjust the High Level Alarm setting to a value that is at least 5.0 inches higher than the
current LN2 level. For example, if the current LN2 level is 5.0 inches, adjust the High
Level Alarm setting to at least 10.0 inches.
3. Adjust the High Level Fill setting to a value that is at least 4.0 inches higher than the
current LN2 level.
4. Adjust the Low Level Fill setting to a value that is at least 3.0 inches higher than the current
LN2 level. If auto fill is enabled, the freezer will begin filling automatically. Press “Fill Stop”
to terminate the fill.
5. Adjust the Low Level Alarm setting to a value that is at least 2.0 inches higher than
the current LN2 Level
6. After one minute, the Low Level Alarm should sound.
7. After alarm verification, return all level settings to their normal values.