Combustion Analysis Procedure - Lochinvar Shield SWR125 Installation & Service Manual

12
Troubleshooting

Combustion Analysis Procedure

1. Shut the water heater down by pressing the UP button for
five (5) seconds.
2. Locate the flue sensor in the vent connection. Remove
the flue sensor and grommet from the unit.
Combustion measurements will be made at this point.
3. Place the water heater in active position by pressing the
UP button for five (5) seconds.
4. Press ENTER plus the UP button for five (5) seconds to
enter Service Mode.
5. Insert the probe from a combustion analyzer into the
hole left by the removal of the flue temperature sensor.
6. Once the water heater has modulated up to full fire,
measure the combustion. The values should be in the
range listed in Table 12G. The CO levels should be less
than 150 ppm for a properly installed unit.
If the combustion is not within the specified range,
reference the Troubleshooting section of this manual for
possible causes and corrective actions.
Table 12G Flue Products
Target
Input Rate
CO
2
High Fire
9.2%
Low Fire
9.0%
Target
Input Rate
CO
2
High Fire
10.8%
Low Fire
10.5%
Table 12H Troubleshooting Chart - Combustion Levels
POSSIBLE CAUSE
Vent/Air Intake Length
or Obstruction
Gas Supply Pressure
Dirty/Damaged Burner
Gas Valve Adjustment
78
Natural Gas
Range
O CO
2 2
4.5% 9.0% - 10.5%
4.8% 8.8% - 9.5%
Propane
Range
O CO
2 2
4.5% 10.5% - 11.5%
5.0% 10.0% - 11.0%
• Refer to Section 2 - General Venting for the proper venting and air intake methods for the
Shield water heater.
• Check for obstructions at the vent/air intake terminals.
• Refer to Section 6 - Gas Connections for the proper gas supply for the Shield water heater.
• Refer to page 66 of this manual for burner removal and cleaning procedures.
• Replace burner if necessary.
• Refer to page 79 of this manual for the gas valve adjustment procedure.
7. Once the combustion analysis is complete, exit Service
Mode.
8. Replace the flue sensor and grommet into the vent
connection.
Note:
9. Place the Shield water heater back into normal operation.
⚠ WARNING
O
2
2.1% - 4.8%
3.9% - 5.2%
O
2
3.5% - 5.0%
4.2% - 5.8%
CORRECTIVE ACTION
Installation & Service Manual
You must replace the flue sensor to prevent
flue gas spillage into the room. Failure
to comply could result in severe personal
injury, death, or substantial property
damage.