Bio-Rad BioLogic Signal Import Module (SIM) - Manual (Page 212)

TROUBLESHOOTING MAINTENANCE AND TROUBLESHOOTING
12-5
Problem Possible Cause Solution
Delivery of liquid is Severe fluctuation in the back-
erratic and the pressure readout indicates an
pressure readout air bubble trapped in one or
on the Controller both of the pumpheads.
status bar is
fluctuating more
Note: Always degas buffers
than 20%. before use.
The pump’s check valves may
need cleaning or replacement.
The backpressure Flow rate may have
displayed on the been changed.
Controller status
bar drops to zero
There may be a tubing
or is much lower or fitting leak.
than expected.
Pump seals may
need replacement.
Check valves may need
cleaning or replacement.
1. Put the AVR7-3 valve into the purge position
and purge the system by pressing the Purge
buttons on the front panel of the Workstation.
2. Stop or Pause the pumps and re-prime. Loosen
the top fitting on the pumphead and force any
trapped air out of the pumphead by squirting
buffer through the priming port using a syringe.
Refer to the maintenance section on how to
prime the Workstation pump and remove
trapped air bubbles. Always use degassed
buffers.
3. To minimize this problem, use degassed buffers
and solutions. Degas buffers by stirring
vigorously under vacuum for approximately 20
minutes. Use a heavy-wall side-arm Erlenmeyer
flask, as standard flasks may implode under
vacuum.
4. Clean (or replace) the check valves (see
section 11.3.3, Routine Maintenance of the
Workstation Pump.)
a. Cleaning: Sonicate check valves in a warm
detergent solution, rinse with deionizied (DI)
water, and re-install.
Replacing: Replace badly clogged or
damaged check valves.
b. Recalibrate the pumps after
cleaning/replacing check valves. Select
Gradient Pump Calibration from the
Utilities drop-down menu.
1. Confirm that the flow rate setting has not been
changed.
2. Re-inspect all tubing connections, especially at
the pump inlet.
3. Replace pump seals. A build-up of crystallized
buffer salts on the rear of the pumphead is a
clear sign for seal replacement. (see Section
11.3.3, Routine Maintenance of the Workstation
Pumps.)
4. Clean or replace check valves. (see Section
11.3.3, Routine Maintenance of the Workstation
Pumps.)