Lochinvar SNR150-100 Combustion Analysis Procedure, Possible Cause, Troubleshooting, Natural Gas

TM

Installation & Service Manual

13 Troubleshooting

Combustion Analysis Procedure

1.Press the SHUTDOWN button on the display until HTR:Off appears in the display window.

2.Remove the screws securing the top panel to the unit. Remove the panel from the unit to gain access to the flue sensor.

3.Locate the flue sensor in the top of the vent connection. Remove the flue sensor and grommet from the unit. Note: Combustion measurements will be made at this point.

4.Press the SHUTDOWN button on the display until HTR:Standby appears in the display window.

5.Locate the pinhole button above the “r” in the Lochinvar logo on the display board (FIG. 11-1). Insert a thin wire (such as a paper clip) into the hole and press the button once and hold for 5 seconds to place the water heater into Service Mode. In Service Mode the water heater will fire at ignition speed and will then modulate up to full fire.

6.Insert the probe from a combustion analyzer into the hole left by the removal of the flue temperature sensor.

7.Once the water heater has modulated up to full fire, measure the combustion. The values should be in the range listed in Table 13G. 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 chart below for possible causes and corrective actions.

Table 13G Flue Products

Natural Gas		Propane
CO2	O2	CO2	O2
8.0% - 10%	3.0% - 6.5%	9.0% - 11%	4.1% - 6.9%

8.Once the combustion analysis is complete, press the SHUTDOWN button on the display board (FIG. 11-1) to take the water heater out of Service Mode. The water heater will go to shutdown and the display will show HTR:Off.

9.Replace the flue sensor and grommet into the vent connection.

10.Replace the top panel on the unit.

11.Place the Shield water heater back into normal operation.

￿WARNING 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.

Table 13F Troubleshooting Chart - Combustion Levels

POSSIBLE CAUSE	CORRECTIVE ACTION
Vent/Air Intake Length	• Refer to Section 2 - General Venting for the proper venting and air intake methods for the
	Shield water heater.
or Obstruction
	• Check for obstructions at the vent/air intake terminals.
Gas Supply Pressure	• Refer to Section 7 - Gas Connections for the proper gas supply for the Shield water heater.
Dirty/Damaged Burner	• Refer to page 56 of this manual for burner removal and cleaning procedures.
	• Replace burner if necessary.
Gas Valve Adjustment	• Refer to page 69 of this manual for the gas valve adjustment procedure.

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