BMK 5000-6000 Boiler OPERATION-SERVICE-MAINTENANCE GUIDE
SECTION 6 – MAINTENANCE
Page
40
of
136
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0124_0A
05/03/2017
Ph.: 800-526-0288
GF-208
4.3 MAIN FLAME DETECTOR
The Main Flame Detector (P/N
65150
) is located on the Blower Flange near the top of the unit
(see Figure 4-1, 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
control panel
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 back plate at the right side 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
ON/OFF switch on the control panel, to the
OFF
position. Disconnect AC power
from the unit.
2.
Remove the left-rear access panel from the unit’s right side panel by removing the 4
Phillips head screws attaching it (Figure 4-2).
3. Disconnect the O2 sensor lead wire by pushing in on the release tab and pulling apart the
connector.
4. Next, loosen and remove the O2 sensor and crush washer from the back plate using a
15/16" open-end wrench.
5.
Thoroughly inspect the O2 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.
