Oxymitter 4000

Instruction Manual

IM-106-340, Rev. 4.0 May 2006

Heater Strut Replacement

This paragraph covers heater strut replacement. Do not attempt to replace the heater strut until all other possibilities for poor performance have been considered. If heater strut replacement is needed, order a replacement heater strut (Table 10-1). Refer to Figure 9-3or Figure 9-4to view the component parts of the Oxymitter 4000.

Use heat resistant gloves and clothing when removing probe. Do not attempt to work on the probe until it has cooled to room temperature. The probe can be as hot as 800°F (427°C). This can cause severe burns.

1.Follow the instructions in "Removal and Replacement of Probe" to remove the Oxymitter 4000 from the stack or duct.

2.For a unit with integral electronics, disconnect electronics per "Replace Entire Integral Electronics (with Housing)", steps 2 through 5.

3.For a unit with remote electronics, remove cover (11, Figure 9-4) from housing (21) along with adapter board (8) and screw (9) from heater strut assembly (1, Figure 9-3).

4.Remove four screws (2, Figure 9-4). Remove the probe from housing (21).

5.Remove tube clamps (29, Figure 9-3)and silicon tubes (28, Figure 9-3)from the CAL and REF gas ports and the CAL and REF gas lines.

6.Loosen, but do not remove, three screws (30, Figure 9-3). The spring tension will release and the heater strut assembly should move up.

7.When the spring tension is released, remove three screws (30). Grasp the wire loop and carefully slide the heater strut assembly (Figure 9-8) out of the probe tube.

8.When replacing the strut, orient the probe so the small calibration gas tube is at the 6 o'clock position of the probe tube. Align the slot on the heater plate with the calibration gas line in the probe tube. Slide the strut into the probe tube. It will turn to align the hole on the back plate of the strut with the calibration gas line. When the hole and the calibration gas line are aligned correctly, the strut will slide in the rest of the way.

9.As the strut installation nears completion, install the guide rod into the calibration gas tube to assist in guiding the calibration gas tube through the hole in the end of the strut.

10.Push down on the back plate of the strut to make sure you have spring tension and then tighten the three screws on the back plate.

11.Replace the CAL and REF gas silicon tubes.

12.For units with integral electronics, install the entire electronics per "Replace Entire Integral Electronics (with Housing)", steps 7 through 13.

9-14

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Emerson Process Management IM-106-340 instruction manual Heater Strut Replacement