MC2: 10/03/12 Page
67
of
90
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
•
Ph: 800-526-0288
GF-115-H
OMM-0083_0B
Modulex MLX Series Gas Fired Boiler System
Operation and Maintenance Manual
Chap 10:
Troubleshooting
Table 10-1: Boiler Troubleshooting – PCB Terminal (Continued)
FAULT
INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
E2:
Low gas
supply
pressure
1. Incorrect supply gas
pressure.
2. Defective Low
Pressure Gas Switch
1. The optimum gas pressure for the Modulex Boiler is 7.0”
W.C., also used as desired pressure in the Combustion
Calibration procedures in Paragraph 6.5.5. The boiler can
be safel y operated at gas pressures ranging from 4.0” W.C.
(min) to 14” W.C. (max) per Gas Supply Design Guide GF-
115-G.
2. Measure gas pressure at the low gas pressure switch. If it is
greater than 2.6” W.C., measure continuity across the
switch and replace if necessary.
E4:
Flame lost
during
ignition
(FLDI)
1. Burner Ground
Screw not installed or
loose.
2. Worn flame detector
3. No spark from Spark
Plug
4. Defective Ignition
Transformer
5. Defective
Ignition/Stepper
(IGST) Board
6. Defective SSOV
7. Contaminated gas
supply (propane)
1. Inspect and install/retighten Burner Ground Screw.
2. Remove and inspect the flame detector for signs of wear.
Replace if necessary.
3. Close the internal gas valve in the boiler. Install and arc a
spark igniter outside the unit.
4. If there is no spark, check for 120VAC at the primary side to
the ignition transformer during the ignition cycle.
5. If 120VAC is not present, the IGST Board in the Control Box
may be defective. Refer fault to qualified service personnel.
6. While externally arcing the spark ignitor, observe open/close
indicator in Safety Shut-Off Valve to ensure it is opening. If
the valve does not open, check for 120VAC at the valves
input terminals. If 120VAC not present, the IGST board in
the Control Box may be defective. Refer fault to qualified
service personnel.
7. Investigate propane quality and switch supply if necessary.
E5:
Flame lost
during run
(FLDR)
1.
Annual maintenance
not done
2.
Air filter (Clogged)
3.
Burner clogged
4.
Heat exchanger
plugged
5.
Combustion
calibration not
correct
6.
Interrupted gas
supply and air
supply
7.
Burner Ground
Screw not installed
or loose.
1.
Perform maintenance
2.
Clean or replace clogged filter
3.
Clean burner
4.
Clean and unclog heat exchanger
5.
Recalibrate combustion
6.
Check and clear obstructions to gas or air supply.
7.
Inspect and install/retighten Burner Ground Screw.
8.
Remove and inspect the flame detector for signs of wear.
Replace if necessary.
9.
Close the internal gas valve in the boiler. Install and arc a
spark igniter outside the unit.
10. If there is no spark, check for 120VAC at the primary side
to the ignition transformer during the ignition cycle.
