Aerco 2.0 benchmark help! Boiler was running fine shut down for about 2 hrs. Started up now has low gas pressure fault cannot clear low presure switch is ok harness check good to plug, 09:18 PM #2. View Profile. Aerco International Inc NSN parts. Get an instant quote for Aerco International Inc NSN components like AP-C-411-CXT PT NO 122001-125, 121616-1.00, 12201, 10923, PL-C-066 ITEM 21. Browse part list at Just NSN Parts. For boiler plants ranging from 2-8 boilers, AERCO’S built-in Boiler Management Sequencer. can be utilized. For heating plants greater than 8 boilers, the ACS (AERCO Control System) provides the right solution. Likewise, Benchmark systems can be easily integrated with a facility-wide Energy Management or Building Automation System. For Benchmark 2.0 Low NOx boilers configured for De-Rated capacity (see para. 2.4.1), if measured gas pressure at the low gas pressure switch is greater than 3.6” W.C., measure continuity across the switch and replace if necessary. Insufficient water level in system 2. Defective water level circuitry.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
(continued)
7. Defective Differential Pressure
Regulator
8. Carbon or other debris on Burner
7. Check gas pressure readings using gauge or manometer into
and out of the Air/Fuel Valve to ensure gas is getting to the
burner.
8. Remove the burner and inspect for any carbon or debris. Clean
and reinstall
FLAME LOSS
DURING RUN
1. Worn Flame Detector or cracked
ceramic.
2. Defective Differential Regulator.
3. Poor combustion calibration.
4. Debris on burner.
5. Blocked condensate drain.
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Check gas pressure readings using a gauge or manometer into
and out of the Air/Fuel Valve to ensure that the gas pressure
into and out of the valve is correct.
3. Check combustion calibration. Adjust as necessary.
4. Remove the burner and inspect for any carbon or debris. Clean
and reinstall.
5. Remove blockage in condensate drain.
HEAT DEMAND
FAILURE
1. The Heat Demand Relays on the
Ignition/Stepper board failed to
activate when commanded
2. Relay is activated when not in
Demand
1. Press CLEAR button and restart the unit. If the fault persists,
replace Ignition/Stepper (IGST) Board.
2. Defective relay. Replace IGST Board.
HIGH EXHAUST
TEMPERATURE
1. Defective exhaust sensor.
2. Carboned heat exchanger due to
incorrect combustion calibration
1. Measure the actual exhaust temperature and continuity of the
exhaust sensor. If the exhaust temperature is less than 475
o
F
and the exhaust sensor shows continuity replace the sensor.
2. If exhaust temperature is greater than 500
o
F, check
combustion calibration. Calibrate or repair as necessary.
HIGH GAS
PRESSURE
1. Incorrect supply gas pressure.
2. Defective SSOV Supply Regulator.
1. Check to ensure gas pressure at inlet of SSOV is 2 psig
maximum.
2. If gas supply pressure downstream of SSOV cannot be lowered,
to 4.8” W.C. (see para. 4.3, step 8), the SSOV Supply Regulator
may be defective. For Benchmark 2.0 Low NOx boilers
configured for De-Rated capacity (see para. 2.4.1), if gas supply
pressure downstream of the SSOV cannot be lowered to
8
-4
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
continued
3. Device proving switch hooked to
interlocks is not closed.
3. Check that 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
1. Measure gas pressure upstream of the supply gas regulator with
the unit firing. Ensure it is at least 5.3” WC (5.5” WC for IRI). For
Benchmark 2.0 Low NOx boilers configured for De-Rated
capacity (see para. 2.4.1), ensure gas pressure upstream of the
supply gas regulator, with the unit firing, is at least 4.0” W.C.
(4.2” W.C. for IRI).
2. Measure gas pressure at the low gas pressure switch, if it is
greater than 4.4” WC measure continuity across the switch and
replace if necessary. For Benchmark 2.0 Low NOx boilers
configured for De-Rated capacity (see para. 2.4.1), if measured
gas pressure at the low gas pressure switch is greater than 3.6”
W.C., measure continuity across the switch and replace if
necessary.
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.
PRG SWTCH CLOSED
DURING IGNITION
Aerco Benchmark Boilers
1. A/F Valve rotated open to purge and
did not rotate to ignition position
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 Control Box. Refer fault to qualified service personnel.
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