Fluke 7008 User Manual page 77

The bath does not achieve low temperatures
The controller does not maintain controller
parameters or parameters are reset each
time the power to the unit is removed
Too much heating or not enough cooling can
cause this problem.
•
Check that the control indicator glows
green showing that the controller is
attempting to cool. The heaters maybe
disabled as a test by temporarily
removing the heater fuses.
•
Insufficient cooling may be caused by
lack of refrigerant due to a leak in the
system Refer to the Charging
Instructions, Section Check the sight
glass to verify the presence of liquid
refrigerant. It may be difficult to tell if the
glass is completely full or completely
empty. Verify by watching the glass
while the compressor is being turned on.
Note: Before performing the memory check,
you need to record the controller calibration
parameters (found in the CAL menu of the
instrument) and any user-adjusted
parameters that you have changed (Such as
the programmable set points and proportional
band).
Memory Check
Doing a memory check is the easiest way to
verify the ability of the battery to maintain
controller parameters.
1. Power off the instrument.
2. Disconnect the instrument from AC
power for 10 seconds.
3. Reconnect the AC power and power on
the instrument.
4. If the display shows InIT and/or the cycle
count shows a low number such as
0002, the battery is spent and should be
replaced. Con- tact a Hart Scientific
Authorized Service Center for
assistance.
5. After replacing the battery, you must
reprogram the calibration and user-
adjustable parameters into the controller.
13
Troubleshooting
13.1 Troubleshooting
13-5