AERCO BMK 3.0 LN Dual Fuel June 2010 - Manual (Page 70)

TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
INTERLOCK
OPEN
1. Interlock jumper not installed or removed
2. Energy Management System does not
have boiler enabled.
3. Device proofing switch hooked up to
interlocks is not closed.
1. Check for a jumper properly installed across the interlock
terminals in the I/O box
2. If there are two external wires on these terminals check any
Energy Management system to see if they have the units
disabled (a jumper may be temporarily installed to see if the
interlock circuit is functioning).
3. Verify that the proving switch for any device hooked to the
interlock circuit is closing and that the device is operational.
LINE VOLTAGE
OUT OF PHASE
1. Line and Neutral switched in AC Power
Box.
2. Incorrect power supply transformer
wiring.
1. Check hot and neutral in AC Power Box to ensure they are not
reversed
2. Check transformer wiring, in AC Power Box, against the power
box transformer wiring diagram to ensure it is wired correctly
LOW GAS
PRESSURE
1. Incorrect supply gas pressure.
2. Defective Low Pressure Gas Switch
3. Fuel Selector Switch is in the OFF
position or was changed while the unit
was running.
1. Measure gas pressure upstream of the supply gas regulator with
the unit firing. Refer to paragraph 2.7.1 to ensure the gas
pressure is correct for the type of fuel and gas train being used.
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.
3. Check Fuel Selector Switch position.
LOW WATER
LEVEL
1. Insufficient water level in system
2. Defective water level circuitry.
3. Defective water level probe.
1. Check system for sufficient water level.
2. Test water level circuitry using the Control Box front panel LOW
WATER TEST and RESET buttons. Replace water level circuitry
if it does not respond.
3. Check continuity of probe end to the shell, change probe if there
is no continuity.
MODBUS COMM
FAULT
1. Boiler not seeing information from
Modbus network. 1. Check network connections. If fault persists, contact qualified
Service Personnel.
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