Watts Aerco Benchmark OMM-0117 Operation And Maintenance Manual page 71

Benchmark 5000-6000 Operation & Maintenance Manual
SECTION 5 – TROUBLESHOOTING GUIDE
TABLE 5-1: Boiler Troubleshooting Procedures
FAULT
INDICATION
Insufficient water level in system.
1.
Defective water level circuitry.
2.
LOW WATER
LEVEL
Defective water level probe.
3.
Unit not seeing information from Modbus
MODBUS 1.
COMMFAULT network.
1. Dirty air filter.
Blockage in the inlet air duct.
2.
3. Gas pressure too high.
O2
Blocked flue.
4.
PERCENTAGE
Blocked condensate trap.
LOW 5.
Blower failure
6.
VFD failure
7.
O % reading <-4%, or >24%
O2 SENSOR 1.
2
MALFUNCTION
Combustion Calibration incorrect.
1.
O2 % OUT OF
RANGE Blocked inlet air duct or louver.
2.
Loose or broken wiring.
1.
OUTDOOR
2. Defective Sensor.
TEMP SENSOR
FAULT
Incorrect Sensor.
3.
OMM-0118_B • GF-203 • 5/9/2019
PROBABLE CAUSES
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
CORRECTIVE ACTION
Check system for sufficient water level.
1.
Test water level circuitry using the C-More Controller front panel
2.
LOW WATER TEST and RESET buttons. Replace water level
circuitry if it does not respond.
Check continuity of probe end to the shell, change probe if there is
3.
no continuity.
Check network connections. If fault persists, contact qualified
1.
Service Personnel.
Remove air filter and clean per Section 4.10, above.
1.
2. Inspect all sections of the duct for foreign materials.
Measure the gas pressure between the SSOV and the Air/Fuel
3.
Valve. It should be 7.9" W.C. ± 0.2" W.C. (2.0 kPa ± 50 Pa).
Check flue for foreign material.
4.
Check condensate trap per Section 4.9, above.
5.
Check blower rotational speed with strobe light and compare to
6.
VFD Hz output: RPM = 57.5 x Hz.
Check VFD faceplate (available from AERCO after-market) using
7.
the VFD manufacturer's troubleshooting documentation.
Check the O offset and gain values in the Calibration menu. If set
1.
2
to 1.0 and 1024 respectively, replace O
Check Combustion Analyzer and recalibrate the boiler.
1.
Unblock air inlet and measure open area for combustion air to the
2.
room.
Inspect Outdoor Temperature sensor for loose or broken wiring.
1.
Check resistance of sensor to determine if it is within specification.
2.
Ensure that the correct sensor is installed.
3.
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