Preliminary And Seasonal Checks; Priming Condensate Trap; Gas Valve Operation; Start Up - Lennox G71MPP SERIES 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.
B−Heating 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 ser-
vice 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.

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.
BEFORE BEFORE PLACING THE UNIT INTO OPERA-
TION, 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 G71MPP is equipped with a gas
control switch. Use only your hand to move the control
switch. Never use tools. If the switch will not move by
hand, do not try to repair it. Call a licensed professional
service technician (or equivalent). Force or attempted re-
pair may result in a fire or explosion.
Placing the furnace into operation:
G71MPP units are equipped with an automatic ignition
system. Do not attempt to manually light burners 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 units with this ignition
system.
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 35)
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 the gas valve switch to the OFF position. See
figure 35.
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.
NEGATIVE AIR
PRESSURE PORT
INLET
SUPPLY
PRESSURE TAP
GAS VALVE SHOWN IN OFF POSITION
8 − Move gas valve switch to the ON position. See figure
35. Do not force.
Page 47
WARNING
GAS VALVE
POSITIVE AIR MANIFOLD
PRESSURE PORT PRESSURE TAP
FIGURE 35
OUTLET