Page 25
Unit Start-Up
 WARNING
Do not use this furnace if any part has been underwater. 
A  ood-damaged  furnace  is  extremely  dangerous. 
Attempts to use the furnace can result in re or explosion. 
Immediately call a qualied 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
If  overheating  occurs  or  if  gas  supply  fails  to  shut  o, 
shut  o  the  manual  gas  valve  to  the  appliance  before 
shutting o electrical supply.
 WARNING
Before attempting to perform any service or maintenance, 
turn the electrical power to unit OFF at disconnect switch.
BEFORE LIGHTING smell all around the appliance area 
for gas. Be sure to smell next to the oor because some 
gas is heavier than air and will settle on the oor.
The gas valve on the EL180UHNE unit is equipped with a 
gas control switch. Use only your hand to move the switch. 
Never use tools. If the switch will not turn or if the control 
switch will not move by hand, do not try to repair it.
Placing the furnace into operation:
EL180UHNE units are equipped with an automatic igni-
tion system. Do not attempt to manually light burners on 
these furnaces. 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 an au-
tomatic ignition system. The Honeywell gas valve is rated 
for ambient temperatures between  -40
0 
F
 
and +175
o 
F.
 WARNING
If you do not  follow these instructions exactly, a re or 
explosion may result causing property damage, personal 
injury or death.
Gas Valve Operation (FIGURE 25)
1 -   STOP! Read the safety information at the beginning 
of this section.
2 -  Set the thermostat to the lowest setting.
3 -  Turn o 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 switch on gas valve to OFF. Do not force. See 
FIGURE 25.
7 -  Wait  ve  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 
instructions. If you do not smell gas go to next step.
GAS VALVE
NEGATIVE AIR
PRESSURE PORT
POSITIVE AIR
PRESSURE PORT
MANIFOLD
PRESSURE TAP
INLET
OUTLET
SUPPLY
PRESSURE
TAP
GAS VALVE SHOWN IN THE ON POSITION
MANIFOLD PRESSURE ADJUSTMENT
(TURN CCW TO INCREASE PRESSURE)
FIGURE 25 
8 -  Move switch on gas valve to ON. Do not force. See 
FIGURE 25.
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 O Gas to Unit” and call your 
service technician or gas supplier.
Turning O Gas to Unit
1 -  Set the thermostat to the lowest setting.
2 -  Turn o all electrical power to the unit if service is to 
be performed.
3 - Remove the upper access panel.
4 - Move switch on gas valve to OFF. Do not force.
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 circuit breaker?
5 -  Is the lter dirty or plugged? Dirty or plugged lters 
willcause the limit control to shut the unit o.
6 - Is gas turned on at the meter?
7 - Is the manual main shut-o valve open?
8 - Is the internal manual shut-o valve open?
9 -  Is the unit ignition system in lock out? If the unit locks 
out again, call the service technician to inspect the 
unit for blockages.