Lennox GCS16 Series, Manual, Page: 37 / 134

Page 37
TABLE 18
FIVE SPEED BLOWER MOTORS
Speed Tap Number
Low
Medium-Low
Medium-High
High
Common
6
5
3
2
1
Medium 4
Blower speed selection is accomplished by changing the
taps in the harness connector at the blower motor (see fig
ure 37). Blower speeds are shown in table 19.
TABLE 19
Unit
208v/230v FACTORY SET BLOWER SPEED
Cool (port)
Heat(port)
High (2)
Med-Hi (3)
Low (5)
208v 230v
-261
-311
-411-50
-411-100
-413-50
-413-100
-511
-513
-651-75
-651-125
-653-75
-653-125
High (2)
High (2)
High (2) Med-Hi (3)
Med-Hi (3)
Med-Hi (3)
Med-Hi (3)
Med-Lo (4)
Med-Lo (4)
Medium (4) Med-Lo (4) Medium (4)
Med-Hi (3)
Med-Hi (3)
Medium (4)
Medium (4)
Med-Lo (5)
Med-Lo (5)
Med-Hi (3)
Med-Hi (3) Med-Hi (3)
Med-Lo (4) Low (5)
Med-Lo (4)
Medium (4) Med-Lo (5) Medium (4)
Med-Hi (3)
Med-Hi (3)
Medium (4)
Medium (4)
Med-Lo (5)
Med-Lo (5)
Each motor port in a leadless motor (figure 37) is analo
gous to speed taps (pigtails) used in previous Lennox
units. Each motor is capable of four or five different speeds
depending on unit (refer to unit wiring diagram). Each unit
is factory wired to provide a single cooling speed and a
single heating speed. The speeds can be changed by
moving the cooling wire or the heating wire to a different
port at the harness connector.
Heating Speed:
Factory blower speeds are listed in a table on the unit wir
ing diagram. Adjust the blower heating speed for proper air
temperature rise (listed on unit rating plate). To measure
temperature rise, place thermometers in the supply and
return air plenums. Turn up thermostat to start the unit. Af
ter plenum thermometers have reached their highest and
most steady readings, subtract thermometer readings.
The difference should be in the range listed on unit rating
plate. If this temperature is high, wire the blower to a high
er speed; if resulting temperature is too low, wire the blow
er to a slower speed. Repeat this procedure until desired
temperature rise is obtained.
Cooling Speed:
Factory blower speeds are listed in a table on the unit wir
ing diagram. Blower performance tables are listed in the
first section of this manual. Section VIII-B-Determining
Unit CFM" shows how to measure discharge static pres
sure. Once discharge static pressure has been deter
mined, compare the value to the blower performance
tables listed in the first section of this manual. If CFM is
low, wire the blower to a higher speed; if CFM is high, wire
the blower to a lower speed. Repeat this procedure until
desired CFM is reached.
BLOWER SPEED TAP SELECTION
208/230V UNITS
UNIT
HARNESS CONNECTOR
DISCONNECT HARNESS PLUG. DEPRESS TAB TO RELEASE
WIRE CONNECTOR. SELECT NEW SPEED PORT. INSERT
WIRE UNTIL CONNECTOR CLICKS IN PLACE.RECONNECT
HARNESS PLUG.
BLOWER MOTOR
TAB
PORT
MOTOR HARNESS
CONNECTOR PORTS
FIGURE 37
1
2
3
4
5
6