Section C - Components
27
C1. Motors
Roof Top Units -
To check the motor, turn the unit circuit
breaker to OFF. With an AC volt meter, verify that the cir-
cuit 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 yel-
low (medium). Some units are 2-speed. If you are check-
ing 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
FIG. C1
into a connector. On these units, disconnect the wires from
the AC power module and do the previous tests between
the motor leads.
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. 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 wire. 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 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 (capaci-
tor). The two-speed has four wires: White (common), Black
(high), Red (low) and Brown (capacitor).
Dual Compressor Units
The units that have dual compressors are Models:
39224.601
and
39424.601
To check the motor, turn the unit circuit breaker or break-
ers OFF. With an AC volt meter, verify that the circuit has
no AC voltage. The wires from the motor connect to a 9-pin
connector. The motor leads are white (common - Terminal
4), black (high - Terminal 6) and red (low - Terminal 7). Set
your ohm meter to its highest scale for these tests. Check
for continuity between the white wire and each of the other
wires.
FIG. C2
FIG. C3
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
