Thermo 42i, Instruction Manual

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Preventive Maintenance
Pump Rebuilding
Thermo Electron Corporation Model 42
i
Low Source Instruction Manual 5-7
3. To ensure proper reassembly, mark the position of the pump head by
using a pencil or other marker to draw a line from the top plate down
across the bottom plate to the pump body. Refer to this reference line
when reassembling the pump head.
4. Remove four screws from top plate.
5. Remove top plate, flapper valve, and bottom plate.
6. Using needlenose pliers, remove clamping disk holding diaphragm and
Teflon® protection wafer onto clamping rod, and remove the diaphragm
and Teflon® wafer.
7. Assemble pump by following above procedure in reverse. Make sure not
to over-tighten clamping disk. Be sure that the Teflon® side of
diaphragm faces up and that the flapper valves cover the holes of the top
and bottom plate.
8. Re-install the cover, reconnect the power cord, and turn instrument
ON.
9. Check that the reaction chamber pressure reads between 150 and 250
mm Hg.