BMK 5000-6000 Boiler OPERATION-SERVICE-MAINTENANCE GUIDE
SECTION 5 – TROUBLESHOOTING GUIDE
OMM-0124_0A
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
67
of
136
GF-208
Ph.: 800-526-0288
05/02/2017
TABLE 5-1: BOILER TROUBLESHOOTING PROCEDURES
FAULT
INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
GAS
PRESSURE
FAULT
(Due to High Gas
Pressure)
1.
Incorrect supply gas pressure.
2.
Defective SSOV Actuator.
3.
Defective High Gas Pressure switch.
1.
Check to ensure gas pressure at inlet of SSOV does not
exceed
14”
W.C. (3487 Pa)
2.
If NATURAL GAS supply pressure downstream of SSOV Actuator
cannot be lowered using the gas pressure adjustment screw to the
range specified in the
Benchmark 5000 – 6000 Installation and
Startup Guide
, OMM-0123 (GF-207), Section 4.5.1, Table 4-1
(Natural Gas) or Section 4.5.2, Table 4-4 (Propane), the SSOV
Actuator may be defective.
3.
Remove the leads from the High Gas Pressure switch. Measure
continuity across the common (C) and normally closed (NC)
terminals with the unit not firing. Replace the switch if continuity does
not exist.
HIGH WATER
TEMP
SWITCH OPEN
1.
Faulty Water temperature switch.
2.
Incorrect PID settings.
3.
Faulty shell temperature sensor.
4.
Unit in MANUAL mode.
5.
Unit setpoint is greater than Over Temperature
switch setpoint.
6.
System flow rate changes are occurring faster
than units can respond.
7.
Refractory failure.
1.
Test the temperature switch to insure it trips at its actual water
temperature setting.
2.
Check PID settings against menu default settings in Section 3. If the
settings have been changed, record the current readings then reset
them to the default values.
3.
Using the resistance charts in the Appendix C, Measure the
resistance of Shell sensor and BTU sensor at a known water
temperature.
4.
If unit is in MANUAL mode, switch to AUTO mode.
5.
Check setpoint of unit and setpoint of Temperature switch; Ensure
that the temperature switch is set higher than the unit’s setpoint.
6.
If the system is a variable flow system, monitor system flow changes
to ensure that the rate of flow change is not faster than what the
units can respond to.
7.
Refractory temperature switches on the end plates are in series with
the water temperature limit control to shut down the boiler if the end
plates get too hot. Replace the refractory at the hottest end plate.
HIGH WATER
TEMPERATURE
1.
See HIGH WATER TEMPERATURE SWITCH
OPEN.
2.
Temp HI Limit setting is too low.
1.
See HIGH WATER TEMPERATURE SWITCH OPEN.
2.
Check Temp HI Limit setting.
