Watts AERCO Benchmark OMM-0136 - Aertrim Maintenance and Troubleshooting

Benchmark Platinum-Edge [II]: Operation-Service Manual
SECTION 9 – AERTRIM OPERATION
OMM-0137_E • GF-211 • 12/13/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 136 of 153
9.6 AERtrim MAINTENANCE and TROUBLESHOOTING
The AERtrim system, which maximizes blower efficiency, depends on the O
2
sensor. The AERtrim
system needs only minimal maintenance. It is recommended that you inspect the oxygen
sensor for accuracy every 12 months by comparing it to a sensor reading from a properly
calibrated flue analyzer. This is strongly advised because contaminated air or gas supplies may
cause impurity buildup and shift the calibration point. An offset value of ±3.0% can be entered in
the O2 Offset parameter in the AERtrim Settings screen (Main Menu → Advanced Setup →
Performance → AERtrim → AERtrim Settings) to correct the reading during manual calibration.
If the sensor has a large amount of offset, a replacement may be required soon.
Occasional software updates to the device may be required.
TABLE 9-1: AERtrim General Warnings
Warning
Cause
Possible Solutions
O2 Percentage Low
O
2
Levels less than 2% for more
than 30 seconds (auto-reset when
valve comes back in range}
Dirty filter or poor combustion
calibration – recalibrate unit
O
2
Offset too low – Increase
Offset value
Bad Sensor-Replace
O2 Sensor Malfunction
O
2
Levels less than -4% or more
than 24% for more than 10 seconds
{manual clearing of this fault is
required}
Bad Sensor-Replace
Communication Issue – check
wires and connections
Warning 02 Level High
O
2
Levels > 9% and < 24% for more
than 30 seconds {auto-reset when
value comes back in range}
Gas Pressure Regulator or Air
Blower Problem, or bad
Combustion Calibration
O
2
Offset too high
Bad Sensor-Replace
O2 Sensor Out of
Range
Sensor auto calibration offset
required is more than ±3%
Reset Unit-Recalibrate Sensor
Bad Sensor-Replace
Bad ECU-Replace (Rare)
O2 Warning Service
Required
If the O
2
level is outside of its limits
for more than 5 minutes.
For example:
1) Reading < Lower Limit
& Blower Voltage = BV Limit
OR
2) Reading > Upper Limit
& Blower Voltage = BV Limit
Gas Supply, Air Filter, or Air
Blower issue
Bad Sensor-Replace