Operating instructions

34
1C. BLOWER MOTOR
1. ROOFTOP UNITS
To check the motor, turn the unit circuit breaker to OFF. With
an AC volt meter, verify that the circuit has no AC volts. On
most units, the wires from the motor connect directly into a 6
or 9-pin connector. The motor leads are white (common), black
(high), red (low) and yellow (medium). Some units are 2-speed.
If you are checking a 2-speed system, disregard the yellow
wire. Set your VOM to the ohms scale. You will perform a
continuity test. Check for continuity between the white wire and
each of the other wires.
Lack of continuity between the white wire and any of the other
wires indicates an open circuit and requires that the motor be
changed. Next, check for continuity between each wire and the
green/yellow wire. If you get continuity, you have a grounded
motor and it must be replaced.
On Models 620315 and 630215, the motor leads do not go into
a connector. On these units, disconnect the wires from the AC
power module and do the previous tests between the motor
leads.
BLOWER
MOTOR
CONDENSER
COIL
2. SINGLE COMPRESSOR UNITS
The units that have a single compressor are Models:
39015.XXX
39025.XXX
39035.XXX
39045.XXX
39115.XXX
39325.XXX
39335.XXX
To check the motor, turn the unit circuit breaker OFF. With an
AC voltmeter, verify that the circuit has no AC voltage.
Next, locate the electric box and remove its cover. The motor
leads will connect to a relay or a power module board and the
run capacitor (see Section 2.3, Wiring). Disconnect the motor
leads.
Set your ohm meter to its highest scale for these tests. Check
for continuity between the white wire and each of the other
wires. Lack of continuity between the white wire and any of the
other wires indicates an open circuit and requires that the motor
be changed. Next, scrape some paint off the motor casing and
check for continuity between each wire and unit casing or the
motor casing. If you get continuity between any of the wires and
the motor casing, you have a grounded motor and it must be
replaced.
There are two types of motors used on these models.
One is a single-speed motor and the other is a two-speed motor
(high and low).
The single speed motor has three wires: White (common),
Black (high) and Brown (capacitor).
The two-speed has four wires: White (common), Black
(high), Red (low) and Brown (capacitor).
SECTION C. UNIT COMPONENTS, DUCTING AND SEALED SYSTEMS