Lochinvar SNA400-125, SNA500-125 Start the water heater, If water heater does not start correctly

TM

Installation & Service Manual

10 Start-up

Start the water heater

1.Read and follow the Operating instructions in FIG.’s 10-2 and 10-3, pages 45 and 46.

If water heater does not start correctly

1.Check for loose connections, blown fuse or service switch off.

2.Is external limit control (if used) open? Is water temperature above 200°F?

3.Is tank set point set below tank temperature?

4.Is gas turned on at meter and water heater?

5.Is incoming gas pressure less than 4 inches w.c.?

If none of the above corrects the problem, refer to the Troubleshooting section of this manual.

Check system and water heater

￿Check water piping

1.Check system piping for leaks. If found, shut down the water heater and repair immediately. (See WARNINGS on pages 43 and 44 (startup) regarding failure to repair leaks.)

2.Vent any remaining air from the system using manual vents. Air in the system will interfere with circulation and cause hot water distribution problems and noise.

￿Check vent piping and air piping

1.Check for gastight seal at every connection, seam of air piping, and vent piping.

￿WARNING Venting system must be sealed gastight to prevent flue gas spillage and carbon

monoxide emissions, which will result in severe personal injury or death.

￿Check gas piping

1.Check around the water heater for gas odor following the procedure on page 35 of this manual (Connecting Gas Supply Piping).

Check flame and combustion

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 10A. 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 10A Flue Products Chart

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

￿WARNING

If you discover evidence of any gas leak, shut down the water heater at once. Find the leak source with a bubble test and repair immediately. Do not start the water heater again until corrected. Failure to comply could result in severe personal injury, death, or substantial property damage.

	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.

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