Watts Aerco Benchmark Series Operation And Service Manual page 137

Benchmark Platinum-Edge: Operation-Service Manual
SECTION 6 – TROUBLESHOOTING
TABLE 10-1: Boiler Troubleshooting Procedures
Fault Probable Causes
Defective SSOV Actuator.
2.
Defective High Gas Pressure switch.
3.
Faulty Water temperature switch.
1.
Incorrect PID settings.
2.
Faulty shell temperature sensor.
3.
HIGH WATER
TEMP SWITCH
OPEN
Unit in Manual mode.
4.
Unit setpoint is greater than Over Temperature
5.
switch setpoint.
System flow rate changes are occurring faster
6.
than units can respond.
See HIGH WATER TEMPERATURE SWITCH
1.
HIGH WATER
OPEN.
TEMPERATURE
Temp HI Limit setting is too low.
2.
Communication fault has occurred between the
1.
IGN BOARD
PMC board and Ignition/Stepper (IGST) board.
COMM FAULT
32 Pin Ribbon cable defective.
2.
OMM-0137_D • GF-211 • 7/16/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Corrective Action
2. If gas supply pressure downstream of SSOV Actuator cannot be
lowered to the range specified in Table 4-1 (Natural Gas) or Table 4-
4 (Propane) in Section 4.4: Combustion Calibration of this guide; the
SSOV Actuator may be defective.
Remove the leads from the High Gas Pressure switch. Measure
3.
continuity across the common (C) and normally closed (NC)
terminals with the unit not firing. Replace the switch if continuity
does not exist.
Test the temperature switch to insure it trips at its actual water
1.
temperature setting.
Check PID settings (Advanced Setup  Performance 
2.
Temperature Control, first 3 items). If the settings have been
changed, record the current readings then reset to default values.
Using the resistance charts in Section 2 of the Benchmark Platinum-
3.
Edge: REFERENCE Manual (GF-212) measure the resistance of
Shell sensor and BTU sensor at a known water temperature.
If unit is in Manual mode, switch to Auto mode (Diagnostic 
4.
Manual Run, set Manual Mode = Enabled).
Check setpoint of unit and setpoint of Temperature switch; Ensure
5.
that the temperature switch is set higher than the unit's setpoint.
If the system is a variable flow system, monitor system flow changes
6.
to ensure that the rate of flow change is not faster than what the
units can respond to.
See HIGH WATER TEMPERATURE SWITCH OPEN.
1.
Check Temp HI Limit setting.
2.
Press CLEAR button and restart unit. If fault persists, contact
1.
qualified Service Personnel.
Replace 32 Pin Ribbon cable.
2.
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