Ametek Thermox CEM O2/TM, Руководство пользователя

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7-6 | Thermox CEM O2/TM
Thermocouple Replacement
Remove power from the sensor and control unit and allow the sensor
to cool before replacing parts inside the sensor.
The tip of the thermocouple is positioned in the furnace so that it is
near, but not touching, the cell housing or the furnace heater coil.
To replace the thermocouple, do the following (see Figure 7-2):
1. Open the sensor cabinet door to expose sensor components.
2. Disconnect thermocouple wires from terminals C and D on the sensor
board. Remove the four screws on the sensor board cover plate to ac-
cess this board.
3. Remove the screw from the thermocouple mounting tab (save the
screw for installing the new thermocouple).
4. Pull the thermocouple straight up and remove it from the furnace.
5. Insert the new thermocouple into the slot in the top of the furnace.
It should go in freely; if necessary, wiggle a little to position without
forcing it in. The thermocouple should be near, but not touching, the
cell housing or furnace heater coil.
6. Put the screw back into the thermocouple mounting tab; this secures
the thermocouple to the furnace.
7. Attach the thermocouple wires to terminals C and D on the sensor
board, observing polarity (yellow wire to terminal C; red wire to ter-
minal D).
8. Using an ohm meter, check for short circuits of the heater coil to the
metal thermocouple sheath. To do this, first disconnect the furnace
wires from sensor board terminals R and S. Check that neither furnace
lead is short circuited to the metal furnace cover. The resistance should
be infinite. If you measure a short circuit, loosen the screw that secures
the thermocouple and relocate slightly until resistance is infinite.
After replacing the thermocouple, apply power to the sensor and allow
it to heat up and stabilize (approximately one hour).
9. Perform a calibration on the system.
NOTE
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NOTE
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