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SECTION 9 TROUBLESHOOTING
TABLE 9-1: Boiler Troubleshooting Procedures
Fault
Probable Causes
Device proving switch hooked to
interlocks is not closed.
Line and Neutral switched in AC
Power Box.
LINE VOLTAGE OUT
OF PHASE
Incorrect power supply
transformer wiring.
Incorrect supply gas pressure.
LOW GAS
Defective Low Gas Pressure
PRESSURE
switch.
Insufficient water level in system.
Defective water level circuitry.
LOW WATER LEVEL
Defective water level probe.
MODBUS
Unit not seeing information from
COMMFAULT
Modbus network.
A/F Valve rotated open to purge
and did not rotate to ignition
position.
Defective or shorted switch.
PRG SWTCH
CLOSED DURING
IGNITION
Switch wired incorrectly.
Defective Power Supply Board or
fuse.
Defective IGST Board.
Defective Purge switch.
No voltage present at switch.
PRG SWTCH OPEN
Switch wired incorrectly.
DURING PURGE
Defective Power Supply Board or
fuse.
Defective IGST Board.
Loose or broken wiring.
OUTDOOR TEMP
Defective Sensor.
SENSOR FAULT
Incorrect Sensor.
RECIRC PUMP
Internal recirculation pump failed.
FAILURE
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Corrective Action
Check that proving switch for any device hooked to the
interlock circuit is closing and that the device is operational.
Check if hot and neutral are reversed in AC Power Box.
Check transformer wiring, in AC Power Box, against the power
box transformer wiring diagram to ensure it is wired correctly.
Measure gas pressure upstream of the SSOV Actuator(s) with
the unit firing. Ensure it is above the value in Table 4-2 (Natural
Gas).
Measure gas pressure at the Low Gas Pressure switch. If it is
greater than 1 inch above the Low Gas Pressure switch setting
in Table 4-2 (Natural Gas) measure continuity across the switch
and replace if necessary.
Check system for sufficient water level.
Test water level circuitry using the Low Water TEST and RESET
buttons on the Controller's front panel. Replace water level
circuitry if it does not respond.
Check continuity of probe end to the shell, change probe if
there is no continuity.
Check network connections. If fault persists, contact qualified
Service Personnel.
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 Edge Controller. Refer fault to qualified service personnel.
If the Air/Fuel Valve does rotate to the ignition position, check
the purge switch for continuity between the N.O. and COM
terminals. If the switch shows continuity when not in contact
with the cam, 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.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
If the air-fuel valve does rotate, check Purge switch for
continuity when closing. Replace switch if continuity does not
exist.
Measure for 24 VAC from each side of the switch to ground. If
24VAC is not present, refer fault to qualified service personnel.
Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals).
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
Inspect Outdoor Temp. sensor for loose or broken wiring.
Check resistance of sensor is within specification.
Ensure that the correct sensor is installed.
Replace recirculation pump.
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