AERCO BMK 6000 Dual Fuel - Manual (Page 123)

Benchmark 6000 DF Installation, Operation & Maintenance Manual
CHAPTER 8 – TROUBLESHOOTING GUIDE
OMM-0096_0B
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Page 123 of 219
GF-141
Ph.: 800-526-0288
03/21/2014
TABLE 8-1: BOILER TROUBLESHOOTING – Continued
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.
2. If gas supply pressure downstream of SSOV Actuator
cannot be lowered to the range of 2.3” ± 0.4” W.C. using
the gas pressure adjustment screw (see section 4.4, step
10 & section 4.5 step 9), 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
Appendix E. 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.