Bock Water heaters OT300-A Installation And Operation Instruction Manual page 40

SECTION VI: MAINTENANCE (cont.)
INSPECT THE VENTING SYSTEM AND BURNER
The vent and combustion air intake system should be checked at least once a year for damage
and blockage. Make sure all joints are secure and that the system is properly supported.
Inspect the outdoor terminals to make sure they are free of obstructions.
Inspect the condensate elbow assembly for blockage every six months. Remove the 3/4" plug
at the end of the trap and pull out any accumulation of sediment. Refer to Figure 5 in Section
IV: Installation / Condensate Elbow Assembly for location of the 3/4" plug. Be careful to not
rotate any portion of the condensate elbow assembly when removing or tightening the plug.
Changing the orientation of the condensate drainage point with the exhaust pipe on the
water heater may adversely effect water heater operation.
F or your safety, removal of the blower assembly and the burner must be performed by a
qualified service technician. All parts must be replaced to their original position prior to
operating the water heater.
The water heater utilizes a forced draft combustion system to draw combustion air to the
burner and remove exhaust gas from the vent. The combustion air intake is under a negative
pressure which may cause unwanted objects to be pulled into the intake vent pipe. Over time,
these objects may collect in the burner and affect burner ignitions and water heater
performance. While not required as a periodic maintenance item, inspecting the burner for
blockage should be done once all other potential causes for ignition failures have been
checked (i.e. the ignitor, flame rod, gas supply pressure, etc.). In order to inspect the burner, a
portion of the overall assembly must be removed for access. Before proceeding, make sure
the power switch is OFF and close the main shut-off valve on the gas supply.
• First, remove the ignitor and flame rod and set aside.
• Second, disconnect the wiring harnesses and the air intake piping from the blower.
• Third, remove the blower, along with other connected components, by removing four screws
at the gas control plus four nuts and washers at the burner mounting flange.
Refer to Figure 31 for a visual location of components.
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CAUTION