Watts AERCO Benchmark BMK5000 Operation And Service Manual page 141

Benchmark Platinum-Edge [ii]: Operation-Service Manual
SECTION 6 – TROUBLESHOOTING
TABLE 10-1: Boiler Troubleshooting Procedures
Fault Probable Causes
SSOV relay failed on IGST board.
1.
Floating Neutral.
2.
SSOV RELAY
FAILURE
Hot and Neutral reversed at SSOV.
3.
Actuator not allowing for full closure of gas
1.
valve.
SSOV powered when it should not be
2.
SSOV SWITCH
OPEN
Defective switch or Actuator.
3.
Incorrectly wired switch.
4.
Air/Fuel Valve unplugged.
1.
Loose wiring connection to the stepper motor.
2.
Defective Air/Fuel Valve stepper motor.
3.
STEPPER
MOTOR
Defective Power Supply Board or fuse.
4.
FAILURE
Defective IGST Board.
5.
Air/Fuel Valve out of calibration
6.
OMM-0137_J • Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
12/20/2022
Corrective Action
Press CLEAR button and restart unit. If fault persists, replace
1.
Ignition/Stepper (IGST) Board.
The Neutral and Earth Ground are not connected at the source and
2.
therefore there is a voltage measured between the two. Normally this
measurement should be near zero or no more than a few millivolts.
3. Check SSOV power wiring.
Observe operation of the Safety Shut-Off Valve (SSOV) through
1.
indicator on the Valve actuator and ensure that the valve is fully
and not partially closing.
If the SSOV never closes, it may be powered continuously. Close
2.
the gas supply and remove power from the unit. Refer fault to
qualified service personnel.
Remove the electrical cover from the SSOV and check switch
3.
continuity. If the switch does not show continuity with the gas valve
closed, either adjust or replace the switch or actuator.
Ensure that the SSOV Proof of Closure switch is correctly wired.
4.
Check that the Air/Fuel Valve is connected to the Edge Controller.
1.
Inspect for loose connections between the Air/Fuel Valve motor
2.
and the wiring harness.
Replace stepper motor.
3.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
4.
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
5.
every second. If not, replace IGST Board.
Perform the stepper motor calibration procedure (
6.
Diagnostics → Subsystems → Air Fuel Valve Stepper
Page 141 of 167
→
Main Menu
.
Motor)