38
C16l.
Relay, DPST (double pole/
single throw) is used on Mod-
els 390XX.XXX.
It controls the compressor.
The relay has a 24 volt AC coil. To check the relay, first
verify all AC volts have been turned off to the unit.
Next, remove the wires from terminals 2, 4, 6 and 8. Verify
the coil (terminals 0 and 1) are not energized (no AC power).
Continuity should not exist between terminals 2 to 4 or ter-
minals 6 to 8. Next, energize the coil (terminals 2 to 4 and
terminals 6 to 8. If the above checks are correct, the relay
is good - DO NOT replace it. If the checks are not correct,
the relay is defective - replace it.
Section C - Components, cont’d.
FIG. C32
C16m. Relay, DPST (double pole/
single throw) is used on
Model 39424.601.
It controls HIGH FAN and LOW FAN on Circuit 1 and 2. If
this relay is not wired correctly, Circuit 1 fan will not operate
with Circuit 1 compressor.
The relay has a 120 volt AC coil. To check the relay, first
verify all AC volts have been turned off to the unit.
Next remove the wires from terminals 2, 4, 6 and 8. Verify
the coil (terminals 0 and 1) are not energized (no AC power).
Continuity should not exist between terminals 2 to 4 or ter-
minals 6 to 8. If the above checks are correct, the relay is
good - DO NOT replace it. If the checks are not correct,
the relay is defective - replace it.
FIG. C33
C17. Printed Circuit Boards
C17a.
Circuit Board for Bi-Metal
Thermostat
The relay board consists of a transformer, compressor re-
lay, two fan relays and other components. If any one of
these are defective, the complete relay board must be re-
placed.
The relay board completes circuits to the fan motor and
compressor depending on what mode switch and tempera-
ture setting is on the thermostat.
Remove the cover from the electric box and verify the red
wire is on terminal RC, black wire is on terminal G, blue
wire is on terminal H and yellow wire is on terminal Y.
With AC power to the relay board, check between termi-
nals RC and G or H. There should be 12 volts DC. If no
voltage is detected, the transformer on the relay board is
defective. Replace the relay board.
If 12 volts DC is available, disconnect power to the unit and
remove the HI FAN wire (black) and the LOW FAN wire
(red) and the compressor wire (large black) from the NO
terminal on the compressor relay on the relay board.
FIG. C34
Next, remove the red, yellow, black and blue wires from
terminals RC, Y, G and H on the relay board. Place a jumper
from terminal RC to terminal Y. Provide power to the unit.
Using an incandescent bulb, check from AC white terminal
(one lead from bulb) to NO terminal on compressor relay
on the relay board (other lead from bulb). The bulb should
illuminate. Remove the jumper from terminal RC to termi-
nal G. Now place one lead from bulb to AC white terminal
and the other lead from bulb to LOW FAN terminal. The
bulb should illuminate. Remove the jumper and the bulb
should not illuminate Next, place a jumper from terminal
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
