Benchmark 6000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
Page
94
of
210
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0086_0D
03/20/14
Ph.: 800-526-0288
GF-133
7.4 O
2
SENSOR
The O
2
sensor (part no. 61026) is located on the back plate at the right side of the unit as shown
in Figure 7-2. As this Figure shows, there is also a gas suction line that supplies a sampling of
the exhaust gases from the exhaust manifold to ensure accurate sampling of the O
2
levels. The
sensor and the suction line may be hot, therefore allow the unit to cool sufficiently before
removing or replacing the O
2
sensor.
NOTE
The O
2
Sensor needs to be replaced only once every 5 years.
The O
2
Sensor is removed and inspected by performing the following procedural steps:
O
2
Sensor Maintenance Procedures
1. Set the
ON/OFF
switch on the control panel, to the
OFF
position. Disconnect AC power
from the unit.
2. Remove the rear right-side panel from the unit by removing the screws at the top and rear
(Figure 7-2).
3. Disconnect the O
2
sensor lead wire by pushing in on the release tab and pulling apart the
connector.
4. Next, loosen and remove the O
2
sensor and crush washer from the back plate using a
15/16" open-end wrench.
5. Thoroughly inspect the O
2
sensor. If corroded, the sensor should be replaced. Ensure that
the hole in the refractory is clean and that the gas sample suction tube is not clogged.
6. Reinstall the O
2
sensor and crush washer on the back plate.
7. Reconnect the sensor lead wire.
8. Reinstall the rear right side panel on the unit.
