13
the full cooling or cooling plus dehumidify mode requested value.
If circuit R to G is open (0 vac) for super dehumidify mode, the
motor delivers reduced airflow to maximize the humidity removal
of the system while minimizing over--cooling.
E. Electric Heat Heating Mode
S
Thermostat closes circuit R to W/W1, or W2.
S
The fan coil delivers the selected electric heat airflow.
F. Heat Pump Heating Mode -- Single speed
S
Thermostat closes circuits R to G and R to Y/Y2.
S
The fan coil delivers single speed heat pump heating airflow.
G. Heat Pump Heating with Auxiliary Electric Heat
Thermostat closes circuits R to G, R to Y/Y2 and/or R to Y1 with
R to W/W1 or W2 (and R to O in the case of defrost).
In the event that electric heating is called for by the thermostat
while the heat pump is also operating in either heating or defrost
modes, the motor will modify its airflow output, if necessary, to
provide an airflow which is defined as safe for the operation of the
electric heater during heat pump operation. That airflow is the
greater of the heat pump heating airflow and the electric heater
only airflow.
Procedure 11 — TROUBLESHOOTING ECM
MOTOR AND CONTROLS
ELECTRICAL SHOCK HAZARD
Failure to follow this caution may result in personal injury.
High voltage is always present at motor. Disconnect power to
unit before removing or replacing connectors or servicing
motor. Wait at least 5 min after disconnecting power before
opening motor.
CAUTION
!
The ECM motor used with this product contains two parts: the
control module and motor winding section. Do not assume the
motor or module is defective if it will not start. Go through the
steps described below before replacing control module, Easy Select
Board or entire motor. The control module is available as a
replacement part.
A. If motor turns slowly:
1. Replace panel. Motor may appear to run slowly if access
panel is removed.
2. It is normal operation to run noticeably slower if G terminal
is not energized in cooling or heat--pump modes.
B. If motor does not run:
Turn off power and check the following:
1. Check 5 amp fuse on Easy Select Board.
2. Check for 24vac on SEC1 and SEC2. If no voltage is
present, check transformer.
3. Check all plugs and receptacles for any deformation which
could cause loose connections. Be sure plugs are fully
seated.
4. Verify that approximately 230vac is present at motor.
5. Verify low--voltage control signals to motor. The motor re-
ceives its control signals through the 12--pin plug (PL--1) on
Easy Select Board and 16--pin plug on wiring harness. (See
Troubleshooting Example.) The combinations of pins ener-
gized will determine motor speed. (See Fig. 20.) See Table 7
for circuit board, low--voltage screw terminals energized
and for voltage present at each pin on 12--pin plug (PL--1).
See Table 7 for pin number on 16--pin plug which should
have voltage when Easy Select Board screw terminals have
24vac.
C. Use following procedure to check control signals:
THERMOSTAT
1. Remove all thermostat wires from Easy Select Board.
2. Jumper screw terminals (1 at a time): R--G, R--Y/Y2, R--Y1,
R--W1. If motor runs in all cases, thermostat is mis--wired,
configured incorrectly or defective. If motor runs in some
cases, but not others, continue to check wiring harness and
circuit board.
WIRING HARNESS
1. Shut off power to unit; wait 5 min.
2. Remove 5--pin plug from motor.
3. Remove 16--pin from motor.
4. Replace 5--pin plug and turn power on.
5. Check for appropriate voltages on 16--pin connector with
screw terminals jumpered. (See Table 7 for values and see
examples below.)
If signals check correctly and motor does not run, inspect wiring
harness for loose pins or damaged plastic that could cause poor
connections. If connections are good, either control module or
motor is defective. If proper signals are not present, check circuit
board using procedure below:
12--PIN PLUG (PL--1) ON EASY SELECT BOARD
1. Unplug harness from board.
2. Check for appropriate voltages on pins with Easy Select
Board screw terminals jumpered. (See Table 7 for values
and see example below.)
If proper signals are not present, replace Easy Select Board. If
present at board and not at 16--pin connector, wiring harness is
defective.
TROUBLESHOOTING EXAMPLE:
Motor is not running on a call for heat--pump heating. System is a
single--speed heat pump.
1. After performing checks in Thermostat section, follow steps
1 thru 5 in Wiring Harness section. Then proceed with ex-
ample.
2. With all thermostat wires removed from Easy Select Board,
place a jumper wire between R and Y/Y2 low--voltage
screw terminals on the Easy Select board.
3. Check Table 7 for pin number on 16--pin connector associ-
ated with the Y/Y2 signal. The correct pin is #14. The far
right column shows that (--) 12vdc should be present
between pin #14 and pin #1 (common) on the 16--pin con-
nector.
4. Set meter to read DC voltage. Place meter between pins #1
and #14 and check for (--) 12vdc (common side of meter on
pin #1). If signal is present, the problem is in the module or
motor. If signal is not, problem is either in wiring harness or
Easy Select Board.
These steps can be repeated for other modes of operation.
To check Easy Select Board:
1. Leave jumper wire in place between R and Y/Y2.
2. Check Table 7 under “Wiring Harness Connection to Easy
Select Board” column and row for pin #14 to see pin# on
Easy Select Board that should have voltage. The correct pin
is #2. The column on far right will show voltage that should
be present between pin #2 and #9 (or #10 common).
3. Place meter between pins #2 and #9 on Easy Select Board
and check for (--) 12vdc.
4. If voltage is present, the wiring harness is bad; if not, the
Easy Select Board is bad.
D. Verify Motor Winding Section:
FV4
C