Watts AERCO Benchmark 2.0LN, Operating & Maintenance Instructions

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TROUBLESHOOTING
8-10
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
continued 4. Defective Air/Fuel Valve stepper
motor.
5. Defective Power Supply Board or
fuse.
6. Defective IGST Board
4. Replace stepper motor.
5. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
6. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES
Refer to Table 8-2 to troubleshoot faults which may occur without a specific fault message being displayed.
TABLE 8-2. BOILER TROUBLESHOOTING WITH NO FAULT MESSAGE DISPLAYED
OBSERVED INCIDENT PROBABLE CAUSES CORRECTIVE ACTION
Hard Light-Off 1. Staged Ignition Ball Valve closed.
2. Clogged/damaged Gas Injector
(Figure 8.2).
3. Defective Staged Ignition Solenoid
(figure 8.2)
1. Open the 1/4” Ball Valve downstream of the SSOV.
2. Remove and inspect Gas Injector to ensure it is not clogged or
damaged.
3. Close the 2” Ball Valve downstream of the Differential Regulator
and the 1/4” Ball Valve downstream of the SSOV. Start the unit
and listen for a “clicking” sound that the Staged Ignition Solenoid
makes during Ignition Trial. If “clicking” sound is not heard after 2
or 3 attempts, replace the Staged Ignition Solenoid.
Fluctuating Gas Pressure 1. Gas pressure going into unit is
fluctuating.
2. Damping Orifice not installed.
1. Stabilize gas pressure going into unit. If necessary, troubleshoot
Building Supply Regulator.
2. Check that the Damping Orifice is installed on the SSOV/
Regulator Actuator (Figure 8.3).
Air/Fuel Valve “hunting” at 80%
Firing Rate
1. IGST and Power Supply Boards
outdated.
1. Check to ensure that the IGST and Power Supply Boards are
Rev. E or higher.