Hoefer GD2000 - Manual (Page 28)

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6. Troubleshooting
problem solution
No power or LED Display Check that the power switch is turned on.
Check that the dryer is plugged into a working receptacle.
Check the fuse(s).
No heat Make sure time is set and the LED colon is blinking.
Make sure the temperature is not set to OFF.
If still no heat, contact your local Hoefer, Inc. distributor
for service.
No vacuum Make sure the tubing connects the vacuum port to the
vacuum pump.
Make sure the vacuum pump is plugged into the vacuum
receptacle on the dryer.
Check that time is set. Vacuum automatically starts
10 seconds after time is set.
Check switches on the vacuum source.
Can’t create vacuum seal Make sure the rubber sealing sheet seals around the entire
inside edge of the recess.
Omit the mylar sheet and use plastic wrap on top of gel.
Check for tears or punctures in the rubber sealing sheet.
Replace it, if necessary.
Gels crack Use thinner gels (≤ 0.75 mm), if possible.
Thin gels rarely crack.
Reduce % T.
Equilibrate gels with 30% ethanol, 2% glycerol for one hour
before drying.
Make sure gel is completely dry before turning off vacuum.
Gels do not dry Do not use > 5% glycerol during pre-drying treatment.
Empty the liquid or cold trap.
Replenish dry ice in the cold trap.
Make sure to place only porous cellophane or filter paper
under the gel. Do not use plastic film or the stiff plastic cover
sheet in the stack below the gel.
Fluors become degraded Follow manufacturer’s handling instructions, paying close
attention to recommended temperature exposure.