LumaSense Technologies M390 - Manual (Page 22)

M390 Manual Maintenance 22
5.4 Furnace Core Disassembly
The graphite core can be replaced without disconnecting cooling or purge tubing. Refer to
exploded views of the furnace core assembly found in the APPENDIX of this manual. Refer to
the enclosed CD that contains video files to help you with the disassembly, assembly and other
cavity replacement issues that may occur. These files on the CD are:
M390-Assemble.mpg - Shows how to install the cavity and quartz tube assembly
M390-Disassemble.mpg – Shows how to remove the cavity and quartz tube
M390-RemovePanels.mpg – How to remove side panels
M390-StartUp.mpg - How to start-up the M390 after replacing a cavity or any time.
M390-CavityStuck.mpg – Sometimes an old cavity may get stuck to the electrode seat.
This video shows how to solve this problem. A special plastic rod has been supplied with
your M390 for this purpose.
M390-CavityTooLong.mpg – When installing a new cavity, the tapered fitting at the
cavity ends may need trimming in order to shorten the length between electrodes to
make the quartz tube seat properly. This video shows how to trim the tapered O.D. on
the cavity.
To disassemble the furnace core:
1. Release the spring retaining block from the rear electrode and slide the "T" shaped
electrode mount toward the rear.
2. Gently twist and pull the cavity assembly apart.
3. If the cavity needs replacing, remove the cavity ends from the tapered seats by twisting
and pulling.
4. Examine the internal components for wear and tear.
5. Replace all defective parts. Usually, only the graphite cavity needs replacing, but if air
was present, the insulating felt may need replacement.
6. If the plated surfaces are discolored, excessive heat may be the cause. Please check with
the factory.
7. Reassemble in reverse order.
Note: The distance between electrode ends should be at least 1/4" less than the quartz
tube.
8. Ensure that a firm electro-mechanical connection is made within the tapered joints. Tap
gently with a rubber mallet to ensure firm joints.
9. Turn on water and check all connections.
10. See Section 4.1 to operate the unit*.
* Keep in mind that the temperature should be gradually increased by 100 °C every
15-20 minutes for the initial cavity baking. A temporary smell of sulfur may be noticed
during this time.