Adjust Pilot Burner
The furnace has a pilot flame to light the main burner. The flarne
should surround 3/8" to 1/2"of the thermocouple. See Figure 16.
To adjust, remove cap from pilot adjusting screw on gas valve.
Turn screw counterclockwise to increase or clockwise to de-
crease flame as required. Replace cap for adjusting screw.
Figure 16 Pilot Burner
10-11-65
Main Burner Flame Check
2. Operate furnace continuously for 15 minutes with all regis-
ters and duct dampers open.
3. Take reading and compare with range specified on rating
plate.
If the correct amount of temperature rise is NOT obtained, it
may be necessary to change blower speed. A higher blower
speed will lower the temperature rise. A lower blower speed
will increase the temperature rise.
Changing Blower Speed
Electrical shock hazard.
Turn OFF power to furnace before changing speed
taps.
Failure to do so can result in personal injury and/or
death.
Allow the furnace to run approximately 10 minutes then inspect
the main burner and pilot flames. See Figure 17.
Check for the following (Figure 17):
• Stable and blue flames. Dust may cause orange tips or
wisps of yellow, but flames MUST NOT have solid, yel-
low tips.
• Flames extending directly from burner into heat ex-
changer.
• 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.
Figure 17 Main Burner
Temperature Rise Check
10-10-78
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 applica-
tion 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 5 ) to determine the blower motor speed set-
tings.
Table 5
Wire Color
Black
Orange*
Blue
Red
Blower Speed Chart
Motor Speed
High
Med-High
Medium
Low
* Med-High speed may not be provided on all models.
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.
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.
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. Attach a jumper between
the "Heat" and "Cool" terminals and the remaining motor
speed lead.
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.
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.
To Next Page
Loading...
Need help?
General
