Milton Roy LINC 21593, Instruction Manual

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I N S T R U C T I O N M A N U A L
M A I N T E N A N C E
Maintenance:
The LINC-L471 and LINC­
L471SC Series electric level
controls have been designed to
be as maintenance free as pos­
sible. However, the component
parts are subject to normal wear
and must be inspected and
replaced as necessary.
Inspection and maintenance fre­
quency depend upon the severi­
ty of service conditions.
Instructions are provided in this
section for maintaining the con­
trols as units, i.e., float and float
arm, relay and switch cartridge.
All the maintenance procedures
below assume that the control
has been removed from service.
The switch and relay can be
serviced with the control
installed. The power must be
disconnected before removing
the relay enclosure cover or
opening the conduit fitting.
Float and Arm
Check the physical clearance
for float operation. The float
must swing freely. Solvent clean­
ing of the float arm chamber
may be required if used in vis­
cous or dirty liquids. If the float
has collapsed or is perforated,
unscrew the float from the float
arm and replace with a new
float. Use Loctite® to secure the
float to the float arm. To remove
the float arm, drive out the pivot
pin using a 1/8" punch. When
installing the float arm, make
certain that the threaded offset
of the float arm is against the
thick wall of the body.
Relay:
To test for proper relay function,
disconnect the switch leads from
the relay socket. Apply appro­
priate voltage to the coil termi­
nals and observe the relay con­
tact closure with an ohmmeter
connected across the common
and normally closed contacts.
Interrupt the coil power supply
several times while observing
the ohmmeter. No movement
indicates a defective relay, coil
or contacts. This procedure
should be repeated for each set
of contacts in service.
To remove a defective relay, simply
pull the relay from the socket and
replace with a new relay.
When ordering a replacement
relay, be certain to specify coil
voltage. After installing a new
relay, reconnect the switch
leads.
Switch:
To test for switch malfunction,
connect an ohmmeter across
the electrical leads and observe
the meter as the float assembly
is mechanically operated. No
meter movement indicates a
switch failure.
To replace a switch on the
LINC-L471 or LINC-L471SC
Series, pull out the switch car­
tridge along with the grommet
through the conduit adapter.
Slide the new switch cartridge
into the body. Route the switch
wired through the grommet and
seat the grommet in the conduit
adapter.
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