Aerco BENCHMARK 2500DF User Manual page 112

Benchmark 2500DF-3000DF Installation, Operation & Maintenance Manual
FAULT INDICATION
1. A/F Valve rotated open to purge and did
PRG SWTCH CLOSED
not rotate to ignition position.
DURING IGNITION
2. Defective or shorted switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or fuse
5. Defective IGST Board
PRG SWTCH OPEN 1. Defective purge switch.
DURING PURGE
2. No voltage present at switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or fuse
5. Defective IGST Board
OUTDOOR TEMP 1. Loose or broken wiring.
SENSOR FAULT
2. Defective Sensor.
3. Incorrect Sensor.
Page 112 of 234
05/21/2014
CHAPTER 8 – TROUBLESHOOTING GUIDE
TABLE 8-1: BOILER TROUBLESHOOTING – Continued
PROBABLE CAUSES
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Phone: 800-526-0288
CORRECTIVE ACTION
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 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).
3. 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. If the air-fuel valve does rotate, check purge switch for continuity when
closing. Replace switch if continuity does not exist.
2. Measure for 24 VAC from each side of the switch to ground. If 24VAC
is not present, refer fault to qualified service personnel.
3. Check to ensure that the switch is wired correctly (correct wire numbers
on the normally open terminals).
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. Inspect Outdoor Temperature sensor for loose or broken wiring.
2. Check resistance of sensor to determine if it is within specification.
3. Ensure that the correct sensor is installed.
OMM-0099_0A
GF-145