Page 38
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 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 LIGHTING
the unit, smell all around the fur-
nace area for gas. Be sure to smell next to the floor be-
cause some gas is heavier than air and will settle on the
floor.
The gas valve on the G51MP is equipped with a gas con-
trol switch (lever). Use only your hand to move the switch.
Never 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:
G51MP units are equipped with a SureLight
®
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 SureLight
®
ignition system.
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 (Figures 55 and 56)
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 −
White Rodgers 36G Gas Valve −
Move gas valve
switch to
OFF
. See figure 55 for the White Rodgers
36G valve.
Honeywell VR8205 Gas Valve −
Move gas valve
switch to
OFF.
See figure 56 for Honeywell VR8205
valve.
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.
