Watts AERCO Benchmark 2.0 LN Operating & Maintenance Instructions page 57

TROUBLESHOOTING
FAULT INDICATION
IGN SWTCH CLOSED 1. Air/Fuel Valve not rotating
DURING PURGE
2. Defective or shorted switch
3. Switch wired incorrectly
4. Defective Power Supply Board or
5. Defective IGST Board
IGN SWTCH OPEN 1. Air/Fuel Valve not rotating to ignition
DURING IGNITION
2. Defective ignition switch
3. Defective Power Supply Board or
4. Defective IGST Board
INTERLOCK 1. Interlock jumper not installed or
OPEN
2. Energy Management System does
8-6
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
PROBABLE CAUSES
fuse
position.
fuse
removed
not have boiler enabled.
CORRECTIVE ACTION
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position. If the valve does not rotate at all or does not
rotate fully open, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air-Fuel Valve or
the Control Box. Refer to qualified service personnel
2. . If the Air/Fuel Valve does rotate to purge, check the ignition
switch for continuity between the N.O. and COM terminals. If the
switch shows continuity when not in contact with the cam
replace the switch.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition position, check
the ignition position switch for continuity between the N.O. and
COM terminals when in contact with the cam.
3. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
4. Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
1. Check for a jumper properly installed across the interlock
terminals in the I/O box
2. If there are two external wires on these terminals check any
Energy Management system to see if they have the units
disabled (a jumper may be temporarily installed to see if the
interlock circuit is functioning).