Barnstead International Thermolyne 859 Series, Service Manual

Page: 110 / 118

Lift Test Procedure
The efficiency of the blower and/or exhaust system is
monitored by a quick test procedure, referred to as the
“lift test”. Steps to perform a lift test:
1. Chamber must be at ambient (room tempera-
ture) condition before attempting to perform a lift
test.
a) Allow the unit to cool to ambient condition.
2. Press the green power button on front display.
a) Allow the unit to complete the diagnostic test
upon power up.
3. Press the “0” key on the keypad.
a) This zeros the balance.
4. Press the “start/stop” key on the keypad.
a) This initiates the blower motor.
5. The green display will indicate a number
approximately 20 seconds after pressing the
“start/stop” key.
a) This number is the negative lift.
6. Record the number on paper.
a) Ideally, the number should be between –3.0
and –8.2
b) Detach the exhaust tubing and repeat the test
to determine if the exhaust system is restricting
the airflow or if the top plenum of the NCAT is
restricting the airflow.
7. Refer to the NCAT cleaning procedure if the lift
test falls out of this range.
110
Maintenance