7-6 | Thermox CG1000 Oxygen Analyzer
Furnace Replacement
Removing the Old Furnace
Figure 7-3. Furnace assembly.
1. Remove the cell mount nut (see the “Cell Replacement” section for
help). The cell and inlet tube can be removed as a single unit.
2. Disconnect thermocouple wires from TB2, TC+ and TC- on the back-
plane board
.
3. Disconnect the furnace wires from TB1, AC and AC on the backplane
board.
4. Remove all inlet tubing. Remove the T-fitting from stainless steel
exhaust tubing. Remove tubing from pressure transducer (top right of
backplane board; remove tubing from flow sensor (small black box on
the left of the backplane board).
5. Place a nut driver on the left and right of the furnace. Take the nut
driver on the left and loosen it until the kep nut can be removed. Pull
the plate, acorn nut, and all-thread piece out to the right and remove.
6. Carefully feed the thermocouple and furnace wires through the hole
in the insulation cover as you remove the furnace insulation cover
from the insulation base. The thermocouple wires and furnace wires
should remain attached to the furnace.
7. Loosen the captive screw on the furnace L-bracket until the furnace is
loosened from the L-bracket.
8. Pull the furnace straight out and remove it from the analyzer.