3
WARNING
Should overheating occur, or the gas supply fail to
shut off, shut off the manual gas valve to the fur-
nace and allow burner to run until furnace cools
down and blower shuts off before shutting off the
electrical supply.
If any abnormalities are observed when checking for cor-
rect operation, such as burner failing to ignite or to turn off,
sooty flame, etc., call your nearest authorized service tech-
nician as shown in the Service Center List included in the
home owner envelope with the furnace.
Combustion Air
In order for the burner flame to burn efficiently, it must re-
ceive adequate combustion air.
The amount of combustion air can be changed by operat-
ing the combustion air adjustment rod located beneath the
gas valve.
The adjustment rod is set at an “average” position at the
factory and may be properly set for many applications.
However, the amount of combustion air required will vary
depending on altitude, actual B.T.U. content of the gas be-
ing used, gas pressure, conversion to another gas, and
other variable factors.
Therefore, it is essential that the burner flame be observed
and any necessary adjustments are made before the fur-
nace is put into service at the final home site. Adjusting the
burner air is considered part of the normal home set---up
procedure and is the responsibility of either the home seller
or buyer, depending on their agreement. Adjustments of
this type are not covered by the Evcon warranty.
CAUTION
Combustion air adjustments must be made only by
a qualified technician. Improper air adjustment
may cause unsafe operation, explosion or asphyxi-
ation.
To adjust the combustion air:
1. Allow the burner to burn for about 10 MINUTES. To light
and operate furnace see label on furnace door.
2. Look through the pilot access door or the observation
window and observe the appearance of the flame.
CAUTION
On models without an observation glass in the pi-
lot door, observe flame by holding the pilot door
open. Use a tool (such as pliers) to avoid being
burned since pilot door will be hot.
3. On Nat. gas, the base of the flame should be blue but
the tips of the flame will be yellow.
See Figure 1.
4. On Propane gas, almost all of the flame will be yellow
although some blue should still be present at the base
of the flame next to the end of the burner.
See Figure 2.
5. If the flame is too yellow, the combustion air should be
increased. If the flame is excessively blue (no yellow)
the combustion air should be decreased.
6. To adjust the combustion air, loosen the lock screw
holding the combustion air rod in place. Push in on the
rod to increase the combustion air. Pull out on the com-
bustion air rod to decrease the combustion air. Tighten
lock screw after adjustment is made. Do not complete-
ly close air damper at any time. Complete closure of air
damper to burner will result in improper operation. See
caution above.
FLAME SPREADER
LOCK SCREW
COMBUSTION AIR
ADJUSTMENT ROD
BASE OF
FLAME BLUE
YELLOW TIPS
Figure 1 --
NATURAL GAS FLAME APPEARANCE
FLAME SPREADER
LOCK SCREW
COMBUSTION AIR
ADJUSTMENT ROD
YELLOW
SOME BLUE
FLAME
MOSTLY BLUE
Figure 2
--- PROPANE GAS FLAME APPEARANCE
BLUE
SOME YELLOW
MOSTLY YELLOW
CAUTION
Always be sure pilot access door is closed before
turning main burner on. Failure to do so may cause
carbon monoxide to be drawn into the living space
and may cause asphyxiation.