Panametrics CGA 351, User Manual, Page: 86 / 119

Chapter 5.
80 CGA 351 User’s Manual
Replacing the Oxygen Sensor Assembly
The oxygen sensor assembly is mounted beneath the sensor furnace and is readily accessible for quick and easy
replacement. The following items are needed to replace the oxygen sensor:
IMPORTANT: For proper operation in the low ranges, the oxygen sensor assembly must be replaced as a unit. Never
attempt to replace just the oxygen sensor itself.
• adjustable wrench
• screwdriver
• pliers
CAUTION!
When replacing the oxygen sensor assembly, do not touch the new oxygen sensor with bare hands.
Handle the assembly by the mounting plate and/or manifold.
IMPORTANT:
These symbols indicate Caution - dangerously hot surfaces and risk of electric shock, respectively:
To remove the defective oxygen sensor assembly, proceed as follows:
WARNING!
There are extremely hot surfaces in the analyzer. Touching these surfaces will result in serious burns.
Use heat-resistant gloves while replacing the oxygen sensor.
1. Remove the inlet and outlet process connections, and open the sensor enclosure cover.
2. Locate the oxygen sensor and the oxygen sensor clips (see Figure 5 on page 87). Use pliers to remove the upper
and lower clips from the oxygen sensor. The clips are easily removed by pulling them away from the oxygen
sensor body.
3. Remove the four screws that secure the sensor/manifold mounting plate to the bottom of the sensor enclosure.
Make sure that the sensor does not hit the sides of the sensor furnace, and carefully slide the sensor assembly
out of the enclosure.
IMPORTANT: Note the orientation of the mounting plate and the manifold while removing the assembly.
Replacing the Oxygen Sensor Assembly (cont.)
To install the new oxygen sensor, complete the following steps:
CAUTION!
When replacing the oxygen sensor assembly, do not touch the new oxygen sensor with bare hands.
Handle the assembly by the mounting plate and/or manifold.
1. Insert the sensor/manifold assembly through the opening in the bottom of the sensor enclosure and into the
sensor furnace. Make sure that the assembly is oriented in the same way as the old assembly.
CAUTION!
If the sensor furnace is hot, insert the new oxygen
sensor slowly. Take 45-60 seconds to fully insert the sensor into the furnace. If the sensor is inserted
too quickly, it will crack.
2. Secure the mounting plate to the bottom of the enclosure with the four screws previously removed.
3. Reinstall the upper and lower clips onto the oxygen sensor body.
4. Connect the inlet and outlet process fittings to the bottom of the sensor enclosure.
5. Close the cover on the sensor enclosure.
6. Calibrate the new oxygen sensor as described in “Calibrating the CGA 351” on page 62.
This completes the replacement of the oxygen sensor assembly.