Burner Assembly Inspection - Watts Aerco BENCHMARK 750 User Manual

Benchmark 750 – 1000 Boiler User Manual - INTERNATIONAL

7.6 BURNER ASSEMBLY INSPECTION

The burner assembly is located at the top of the unit's heat exchanger. The burner assembly
may be hot. Therefore, allow the unit to cool sufficiently before removing the burner assembly.
The following parts will be required for reassembly after burner inspection:
Part No.
81143 Burner Gasket (1 each)
81048 Flame Detector Gasket (1 each)
81064 Blower Gasket
To inspect or replace the burner assembly, proceed as follows:
Burner Assembly Inspection and Maintenance Procedures
1. Set the ON/OFF switch on the control panel to the OFF position. Disconnect AC power
from the unit and turn off the gas supply.
2. Remove the top shroud from the unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
3. Disconnect the lead wire from the flame detector installed on the burner plate. See Figure
7-2.
4. Remove the two (2) screws securing the flame detector to the plate. The flame detector is
secured to the burner plate with one (1) #10-32 screw and one (1) #8-32 screw.
5. Remove the flame detector and gasket from the burner plate.
6. Disconnect the cable from the igniter-injector.
7. Using a 7/16" open-end wrench, disconnect the compression nut securing the gas injector
tube of the igniter-injector to the elbow of the staged ignition assembly (see Figure 7-2).
Disconnect the staged ignition assembly from the igniter-injector.
8. Next, loosen and remove the igniter-injector from the burner plate using a 1" open-end
wrench.
9. Disconnect the unit wiring harness connectors from the air/fuel valve and blower motor.
10. Disconnect the wire leads connected to the Blower Proof switch and Blocked Inlet switch
(Figure 7-4 and Figure 7-5).
11. Disconnect the gas train from the air/fuel valve by removing the four (4) 1/2" bolts and
nuts (Figure 7-4).
12. Disconnect the flex hose from the air/fuel valve by loosening the hose clamp.
13. Remove the four 5/16-18 hex head screws securing the blower to the burner plate
(Figure 7-5).
14. Remove the blower and air/fuel valve from the burner plate by lifting straight up. Also,
remove the blower gasket.
15. Remove the eight (8) 3/8-16 nuts from the burner flange (Figure 7-4) using a 9/16"
wrench.
The burner assembly weighs approximately 25 pounds (11.3 kg).
Page 90 of 170
11/03/2016
CHAPTER 7 – MAINTENANCE
Description
NOTE
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
OMM-0119_0A
GF-130-I