16
441 01 2610 00
NOTE:
Adjustment screw cover
MUST
be placed on gas valve be-
fore reading manifold pressure and operating furnace.
3. For altitudes up to 2000
¢
, set pressure to value shown in
Table 2
. For altitudes between 2000
¢
to 8000
¢
, see Section
6.
”Gas Supply and Piping”
for correct pressure value.
Adjust Pilot Burner
The furnace has a pilot flame to light the main burner. The flame
should surround
3
/
8
²
to
1
/
2
²
of the flame rod. See
Figure 14.
To ad-
just, remove cap from pilot adjusting screw on gas valve. Turn
screw counterclockwise to increase or clockwise to decrease
flame as required. Replace cap after adjusting screw.
Pilot Burner
Figure 14
Proper Flame
Adjustment
Flame Rod
Hot Surface
Igniter
10--11--65
Main Burner Flame Check
Allow the furnace to run approximately 10 minutes then inspect
the main burner and pilot flames. See
Figure 15
.
Check for the following (
Figure 15
):
·
Stable and blue flames. Dust may cause orange tips or
wisps of yellow, but flames
MUST NOT
have solid, yellow
tips.
·
Flames extending directly from burner into heat exchanger.
·
Flames do
NOT
touch sides of heat exchanger
If any problems with main burner flames are noted, it may be nec-
essary to adjust gas pressures, or check for drafts.
Main Burner
Burner Face
10--10--78
Figure 15
Temperature Rise Check
The blower speed
MUST
be set to give the correct air temperature
rise through the furnace as marked on the rating plate. Tempera-
ture rise is the difference between supply and return air tempera-
tures.
To check temperature rise,use the following procedure:
1. Place thermometers in supply and return air registers as
close to furnace as possible, avoiding direct radiant heat from
heat exchangers.
2. Take readings and compare with range specified on rating
plate.
3. If the temperature rise is not in the correct range, the blower
speed must be changed. A higher blower speed will lower the
temperature rise. A lower blower speed will increase the tem-
perature rise.
Changing Blower Speed
ELECTRICAL SHOCK HAZARD.
Failure to do so can result in death, personal injury
and/or property damage.
Turn OFF power to furnace before changing speed
taps.
!
NOTE
: The speed taps that the manufacture sets from the factory
for this product are based on a nominal 400 CFM per ton cooling
and the basic mid range on the temperature rise for heating.
Since the manufacturer cannot establish the static pressure
that will be applied to the unit, it is the responsibility of the
installer dealer/contractor to select the proper speed taps for
the application when the unit is installed.
If it is necessary to change speeds, refer to steps below.
1. Refer to
Furnace Wiring Diagram
for location of the heating
and cooling speed taps located on the electronic fan control
as well as location of unused blower motor speed leads. Use
the chart (
Table 6
) to determine the blower motor speed set-
tings.
Table 6
Blower Speed Chart
Wire Color
Motor Speed
Black
High
Orange
*
Med--High
Blue
Medium
Red
Low
*
Med--High speed may not be provided on all models.
2. Change the heat or cool blower motor speed by removing the
motor lead from the “
Heat
” or “
Cool
” terminal and replace it
with the desired motor speed lead from the
“Unused Motor
Lead
” location. Connect the wire previously removed from
the “
Heat
” or “
Cool
” terminal to the vacated
“Unused Motor
Lead
” terminal.
3. If the same speed must be used for both heating and cooling,
remove the undesired motor speed lead from the
“Heat
” or
“Cool
” terminal and connect that lead to the open terminal at
“Unused Motor Lead
” location or tape off. Attach a jumper
between the “
Heat
” and “
Cool
” terminals and the remaining
motor speed lead.
Note
: When using the same speed on motors with (4) speed
leads, it will be necessary to tape off the terminal of the motor
speed lead removed from the “
Heat
” or “
Cool
” terminal with
electrical tape since an open terminal will not be available at
the
“Unused Motor Lead
” location.
Continuous Fan Operation
A terminal is provided on the electronic fan control located in the
circulating blower compartment for operation of the continuous
fan option. This connection is intended for the low speed motor
