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L1
(HOT)
L2
FAN RELAY
LOCAL ALARM
Fig. 5. Hookup providing freeze protection by shutting
down fan with line powered local alarm.
LINE 2
M2
CONDUIT
TO
FAN
RELAY
JUNCTION
BOX
Fig. 6. Providing separate conduit for switched ac and
automation input wiring.
LINE 2
LINE 1
M1
M2
C792
LINE 1
M1
36 INCH
(914 MM)
MAXIMUM
TO
AUTOMATION
SYSTEM
Adjustment
Turn the setpoint adjustment screw (Fig. 1) on the top of the
controller case to the value called for on the job drawings.
NOTES:
1.
The setpoint adjustment is limited to 35-55°F
(2-13°C) by an internal physical stop.
2.
The setpoint is factory set at 35°F. Setpoint is the
temperature at which LINE 1 to M1 contacts close
and LINE 2 to M2 contacts open on a temperature
fall. The controller differential is fixed at 5°F (3°C)
nominal and is additive to the setpoint.
3.
The operating point drops for elevations above
sea level. To compensate, increase the setpoint
adjustment 1°F (0.6°C) above the required set-
point for each 1000 feet (305m) above sea level.
CHECKOUT
Because of the L482A limited setpoint range, operational
checkout can be difficult. Use one of the following methods to
verify proper controller operation:
1. If the ambient temperature is below 50°F (10°C):
a. Turn the setpoint adjustment through the ambient
temperature and note the switch action.
b. When the setpoint is increased to equal the ambient
temperature:
(1) LINE 1 to M1 contacts should close.
(2) LINE 2 to M2 contacts should open.
c. Decreasing the setpoint to 5°F (3°C) below the
ambient temperature should not affect the contact
positions.
d. Pushing the manual reset button should:
(1) Open contacts LINE 1 to M1
(2) Close contacts LINE 2 to M2.
2. If the ambient temperature is above 50°F (10°C):
a. Immerse at least one foot of the element in ice water
(or wrap same in ice).
b. As the element drops through the setpoint:
(1) LINE 1 to M1 contacts should close.
(2) LINE 2 to M2 contacts should open.
C793
c. Remove the element from the ice water (or ice
wrapping).
d. As ambient temperature rises to 5°F (3°C) the set-
point, there should be no effect on contact positions.
e. Pushing the manual reset button should:
(1) Open contacts LINE 1 to M1.
(2) Close contacts LINE 2 to M2.
3
L482A LOW LIMIT CONTROLLER
95-7432–1
996-496 Rev. A
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