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Changing Blower Speed
(*9MPT Models)
ELECTRICAL SHOCK HAZARD.
Failure to do so could result in death or personal
injury.
Turn OFF power to furnace before changing
speed taps.
!
WARNING
NOTE
: The speed taps that the manufacturer 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 in-
staller dealer/contractor to select the proper speed taps for
the application when the unit is installed.
REDUCED FURNACE LIFE HAZARD
Failure to properly set the air temperature rise may
result in reduced furnace life.
Use
ONLY
the following blower motor speed taps for
setting air temperature rise.
Blower Motor
Model Sizes
Speed Taps
Heat High
Heat Low
Hi (BLK)
All
None
Med--Hi (O)
All
All
Med Lo (BL
All
All
Lo (R)
None
125L20
!
CAUTION
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 furnace control as
well as location of unused blower motor speed leads. Use
the chart (
Table 9
) to determine the blower motor speed
settings.
Table 9
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 “
HI Heat or Lo Heat
” or “
Cool
” terminal
and replace it with the desired motor speed lead from the
“M1” or “M2
” location. Connect the wire previously removed
from the “
Hi Heat or Lo Heat
” or “
Cool
” terminal to the va-
cated
“M1” or “M2
” terminal.
3. If the same speed must be used for both heating and cooling,
remove the undesired motor speed lead from the “
Hi Heat or
Lo Heat
” or
“Cool
” terminal and connect that lead to the open
terminal at
“M1” or “M2
” location or tape off. Attach a jumper
between the “
Hi Heat or Lo 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 “
Hi Heat or Lo Heat
” or “
Cool
”
terminal with electrical tape since an open terminal will not be
available at the
“M1” or “M2
” location.
Continuous--Fan Operation using “G”
*9MPT Models
Energizing the ”G” terminal on the furnace control provides contin-
uous fan operation. This is done by connecting the G terminal of
the thermostat to the G terminal on the furnace control. When the
FAN switch is turned from auto to ON the fan will operate continu-
ously at ”LO HEAT” speed. EAC will be energized in this mode.
NOTE: In heating, the fan will turn off during furnace ignition and
warm up then restart at heating speed.
*9MPTV Models
Energizing the ”G” terminal on the furnace control provides contin-
uous fan operation. This is done by connecting the G terminal of
the thermostat to the G terminal on the furnace control. When the
FAN switch is turned from auto to ON the fan will operate continu-
ously at ”LO HEAT” speed. EAC will be energized in this mode.
NOTE: No hard--wired continuous fan mode option available for
variable speed applications.
NOTE: In heating, the fan will continue to operate at continuous fan
speed until the furnace control calls for heat speed after warm--up.
Then the fan will run at heat speed.
Hard--Wired Continuous Fan Operation (*9MPT ONLY)
A terminal is provided on the furnace control located in the circulat-
ing air blower compartment for operation of the continuous fan op-
tion. This connection is intended for the low speed motor tap, and
has a lower contact rating (8 amps) than the heat and cool taps.
When the low speed blower lead is connected to this terminal, this
will provide low speed blower operation whenever the other three
speeds (“
Hi Heat or Lo Heat
” or
Cool
) are not energized.
Thoroughly check the system after modification to ensure the
proper operation of the circulating air blower in all modes of opera-
tion.
Separate speed selections for Heat, Cool, and
Continuous--Fan
Connect low speed lead from circulating air motor to the
“Cont”
terminal at the furnace control coard. The appropriate motor leads
should already be connected to the “
Hi Heat and Lo Heat
” and
“Cool”
terminals.
Heating and Continuous--Fan Speed the Same
If it is necessary to operate the low heating speed and continuous--
fan speed using the same blower speed, connect a jumper be-
tween the
“Lo Heat”
and
“Cont”
terminals on the furnace control.
Note:
There should be only ONE motor lead going to the
“Lo
Heat”
and
“Cont”
terminals.
Hard Wired Continuous Fan Operation
A terminal is provided on the furnace control board located in the
circulating blower compartment for operation of the continuous fan
option. This connection is intended for the low speed motor tap,
and has a lower contact rating (8 amps) than the heat and cool
taps. When the low speed blower lead is connected to this termi-
nal, this will provide low speed blower operation whenever the oth-
er three speeds
(Lo Heat
or
Hi Heat
or
Cool
) are not energized.
Содержание *9MPT050F12
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