Iii-Start-Up - Lennox ML193UH045P36B Unit Information

III-START‐UP
A-Preliminary and Seasonal Checks
1 - Inspect electrical wiring, both field and factory installed
for loose connections. Tighten as required.
2 - Check voltage at disconnect switch. Voltage must be
within range listed on the nameplate. If not, consult the
power company and have voltage condition corrected
before starting unit.
3 - Inspect condition of condensate traps and drain as­
sembly. Disassemble and clean seasonally.
B-Heating Start‐Up
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. Use only your hand to move the switch. Never
use tools. If the the switch will not move by hand, replace
the valve. 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 a SureLight ignition sys­
tem. Do not attempt to manually light burners on this fur­
nace. 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 units with SureLightt ignition
system.
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 again wait for the combustion air inducer to
stop. At this point, the trap should be primed with suffi­
cient water to ensure proper condensate drain opera­
tion.
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 54)
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 54.
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 54.
MANIFOLD
PRESSURE
ADJUSTMENT
SCREW
INLET
PRESSURE
PORT
GAS VALVE SHOWN IN ON POSITION
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.
4 - Move gas valve switch to OFF.
5 - Replace the upper access panel.
Failure To Operate
If the unit fails to operate, check the following:
1 - Is the thermostat calling for heat?
2 - Are access panels securely in place?
3 - Is the main disconnect switch closed?
4 - Is there a blown fuse or tripped breaker?
5 - Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6 - Is gas turned on at the meter?
7 - Is the manual main shut‐off valve open?
8 - Is the internal manual shut‐off valve open?
9 - Is the unit ignition system in lockout? If the unit locks
out again, inspect the unit for blockages.
Page 40
MANIFOLD
PRESSURE
OUTLET
FIGURE 54