BMK 5000-6000 Boiler OPERATION-SERVICE-MAINTENANCE GUIDE
SECTION 7 – TROUBLESHOOTING GUIDE
Page
70
of
136
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0124_0A
05/03/2017
Ph.: 800-526-0288
GF-208
TABLE 5-1: BOILER TROUBLESHOOTING PROCEDURES
FAULT
INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
4.
Blocked flue.
5.
Blocked condensate trap.
6.
Blower failure
7.
VFD failure
4.
Check flue for foreign material. Measure pressure at exhaust manifold
and compare to pressure map (Figure 8-1).
5.
Check condensate trap per section 7.8.
6.
Check blower rotational speed with strobe light and compare to VFD Hz
output: RPM = 57.5 x Hz.
7.
Check VFD faceplate (available from AERCO after-market) using the
VFD manufacturer’s troubleshooting documentation.
O2 SENSOR
MALFUNCTION
1.
O
2
% reading <-4%, or >24%
1.
Check the O
2
offset and gain values in the Calibration menu. If set to 1.0
and 1024 respectively, replace O
2
sensor
O2 % OUT OF
RANGE
1.
Combustion Calibration incorrect.
2.
Blocked inlet air duct or louver.
1.
Check Combustion Analyzer and recalibrate the boiler.
2.
Unblock air inlet and measure open area for combustion air to the
room.
OUTDOOR TEMP
SENSOR FAULT
1.
Loose or broken wiring.
2.
Defective Sensor.
3.
Incorrect Sensor.
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.
PRG SWTCH
CLOSED
DURING
IGNITION
1.
A/F Valve rotated open to purge and did not rotate
to ignition position.
2.
Defective or shorted switch.
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 C-More Controller. 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).
