Benchmark 5000-6000 Operation & Maintenance Manual
SECTION 4
– MAINTENANCE
OMM-0118_B
•
GF-203
•
5/9/2019
Technical Support
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4.3 MAIN FLAME DETECTOR
The Main Flame Detector (
Replacement Kit P/N
65182
) is located on the Blower Flange near
the top of the unit (see Figure 4-1a, above). The Main Flame Detector may be hot. Allow the unit
to cool sufficiently before removing the Main Flame Detector. Inspect or replace the Main Flame
Detector as follows:
Main Flame Detector Maintenance Instructions
1. Set the
C-More Control
ler’s ON/OFF switch to the
OFF
position. Disconnect AC power
from the unit.
2. Remove the front panel from the unit by grasping the top handle and pulling straight out.
3. Disconnect the Main Flame Detector lead wire. Be careful not to yank the wire when it
pops off the Main Flame Detector.
4. Remove the Main Flame Detector from the Blower Flange.
5. Thoroughly inspect the Main Flame Detector. If eroded, the detector should be replaced.
Otherwise clean the detector with a fine emery cloth. Replacement is necessary every 24
months.
6. Apply a small amount of high temperature TFE-Based thread sealant and reinstall the Main
Flame Detector on the Blower Flange.
7. Reconnect the Main Flame Detector lead wire.
8. Replace the front panel on the unit.
4.4 O
2
SENSOR
The Lean Oxygen Sensor (P/N
61026
) is located on the burner
’s rear plate, on the rear of the
unit, as shown in Figure 4-2. 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 Instructions
1. Set the
C-
More Controller’s ON/OFF switch to the
OFF
position. Disconnect AC power
from the unit.
2. Remove the O
2
Sensor Cover from the unit’s back panel by removing the cover’s 4 Phillips
head screws (see Figure 4-2).
WARNING!
DO NOT
remove the units back panel without first lifting the Air Eductor assembly off the
opening behind the 0
2
Sensor Cover and holding it in place with a length of cord or wire.
3. Disconnect the O
2
sensor lead wire by pushing in on the release tab and pulling apart the
connector.
