Owner manual

4 ■ User’s Manual Watlow Series 142
Figure 4 — System wiring example.
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WARNING:
Install high or low temperature limit control protection in sys-
tems where an overtemperature fault condition could present a
fire hazard or other hazard. Failure to install temperature limit
control protection where a potential hazard exists could result
in damage to equipment and property, and injury or death to
personnel.
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CAUTION:
Watlow mercury relay loads must have a unity power factor.
For RESISTIVE LOADS ONLY.
Series 142
142A - 3 _ _ _ - 1200
Safety Limit Control
988A-2BA0-0000
Rear View
9
10
12
13
21 22 11
N.O.
High Limit
Mechanical
Contactor
N.C. N.O.
COM
L2
Load
Power
Heat
Load
(+)
(-)
Fuse
L1
L2
Momentary Switch
Manual Reset for Limit Control
Fuses
Fuse
L1
Load
Power
Control
Power
N.O.
COM
Earth
Ground
Indicator
turns on
when limit trips
Process
Sensor
L2
L1
Limit Sensor
Limit
Power
- +
Thermo-
couple
System Wiring Example