Lennox International Inc ML193UH Unit Start-Up, Placing the furnace into operation

Unit Start-Up

FOR YOUR SAFETY READ BEFORE OPERATING

WARNING

Do not use this furnace if any part has been under­ water. A flood-damaged furnace is extremely dan­ gerous. Attempts to use the furnace can result in fire or explosion. Immediately call a qualified service technician to inspect the furnace and to replace all gas controls, control system parts, and electrical parts that have been wet or to replace the furnace, if deemed necessary.

WARNING

Danger of explosion. Can cause injury or product or property damage. Should the gas supply fail to shut off or if overheating occurs, shut off the gas valve to the furnace before shutting off the electrical supply.

CAUTION

Before attempting to perform any service or mainte­ nance, turn the electrical power to unit OFF at dis­ connect switch.

BEFORE LIGHTING the unit, smell all around the furnace area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

The gas valve on the ML193UH is equipped with a gas con­ trol switch (lever). Use only your hand to move switch. Nev­ er use tools. If the the switch will not move by hand, do not try to repair it. Force or attempted repair may result in a fire or explosion.

Placing the furnace into operation:

ML193UH units are equipped with an automatic hot sur­ face ignition system. Do not attempt to manually light burn­ ers on this furnace. Each time the thermostat calls for heat, the burners will automatically light. The ignitor does not get hot when there is no call for heat on these units.

Priming Condensate Trap

The condensate trap should be primed with water prior to start-up to ensure proper condensate drainage. Either pour 10 fl. oz. (300 ml) of water into the trap, or follow these steps to prime the trap:

1 - Follow the lighting instructions to place the unit into op­ eration.

2 - Set the thermostat to initiate a heating demand.

3 - Allow the burners to fire for approximately 3 minutes.

4 - Adjust the thermostat to deactivate the heating de­ mand.

5 - Wait for the combustion air inducer to stop. Set the thermostat to initiate a heating demand and again al­ low the burners to fire for approximately 3 minutes.

6 - Adjust the thermostat to deactivate the heating de­ mand and wait for the combustion air inducer to stop. At this point, the trap should be primed with sufficient water to ensure proper condensate drain operation.

WARNING

If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or death.

Gas Valve Operation (Figure 61)

1 - STOP! Read the safety information at the beginning of this section.

2 - Set the thermostat to the lowest setting.

3 - Turn off all electrical power to the unit.

4 - This furnace is equipped with an ignition device which automatically lights the burners. Do not try to light the burners by hand.

5 - Remove the upper access panel.

6 - Move gas valve switch to OFF. See figure 61.

7 - Wait five minutes to clear out any gas. If you then smell gas, STOP! Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instruc­ tions. If you do not smell gas go to next step.

8 - Move gas valve switch to ON. See figure 61.

MANIFOLD	MANIFOLD
PRESSURE	PRESSURE
ADJUSTMENT	OUTLET
SCREW
INLET
PRESSURE
PORT
GAS VALVE SHOWN IN ON POSITION

FIGURE 61

9 - Replace the upper access panel.

10- Turn on all electrical power to to the unit.

11- Set the thermostat to desired setting.

NOTE - When unit is initially started, steps 1 through 11 may need to be repeated to purge air from gas line.

12- If the appliance will not operate, follow the instructions “Turning Off Gas to Unit” and call your service techni­ cian or gas supplier.

Turning Off Gas to Unit

1 - Set the thermostat to the lowest setting.

2 - Turn off all electrical power to the unit if service is to be performed.

3 - Remove the upper access panel.

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