Watts AERCO Benchmark BMK750 Operation And Service Manual page 146

Benchmark with Edge [I]: Operation-Maintenance Manual
SECTION 9 – TROUBLESHOOTING
TABLE 9-1: Boiler Troubleshooting Procedures
Fault Probable Causes
Blower stopped running due to
1.
thermal or current overload.
Blocked Blower inlet or inlet
2.
air filter.
Blockage in Blower Proof
3.
switch.
Blockage in Blocked Inlet
4.
switch.
Defective Blower Proof switch.
5.
Defective Blocked Inlet switch.
6.
AIRFLOW
FAULT
Bad inlet air temperature
7.
DURING
sensor.
IGNITION
Defective temperature
8.
sensor.
Loose wire connection
9.
between the Blower and the
Controller.
Defective Air-Fuel Valve
10.
potentiometer.
Hard light.
11.
OMM-0145_A99 • GF-218 • Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
9/18/2019
Corrective Action
Check combustion blower for signs of
1.
excessive heat or high current drain that may
trip thermal or current overload devices.
Inspect the inlet to the combustion blower
2.
including the air filter at the air/fuel valve for
signs of blockage.
Remove the Blower Proof switch and inspect
3.
for signs of blockage, clean or replace as
necessary.
Remove the Blocked Inlet switch and inspect
4.
for signs of blockage, clean or replace as
necessary.
Check the continuity of the Blower Proof
5.
switch with the combustion blower running. If
there is an erratic resistance reading or the
resistance reading is greater than zero ohms,
replace the switch.
Turn off unit and check the continuity of the
6.
Blocked Inlet switch. If there is an erratic
resistance reading or the resistance reading is
greater than zero ohms, replace the switch.
Check the actual inlet air temperature reading
7.
and measure resistance at the Sensor
Harness connection P1. Verify that the
reading conforms to the values shown in
Section 2 of the Benchmark 750-6000 with
Edge [i]: Reference Manual (OMM-0146, GF-
219).
Refer to CORRECTIVE ACTION 7 and verify
8.
that the voltage conforms to the values shown
in Section 2 of the Benchmark 750-6000 with
Edge [i]: Reference Manual (OMM-0146, GF-
219).
Check wire connection from the Blower motor
9.
to the Secondary Power Panel.
Check Air/Fuel Valve position at 0%, 50%
10.
and 100% open positions. The positions on
the Valve Position bargraph should match
the readings on the Air/Fuel Valve dial.
Check igniter-injector for soot or erosion of
11.
electrode. Check injector solenoid valve to
insure proper open/close operation.
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