Operating instructions
40018
r'a
FEW
SNAPSWITCH
ELECTRICAL
RATINGS
Standard
Differential
15
A,125-250
VAC
0.50
A,
125 VDC
0.25
A, 250
VDC
Narrow
Differential:
15
A,125-250 VAC
DielectrÍc
Strength:
Not
less
than 15OO VDC
or
lSOO
RMS-AC
for
one
mlnute
between
the
case
and
terminaÌs
connected
in
parallel
ACTUÁfING
PIN
-
L
8EI-LOWS
EXPANDS PROVIOING
Âcfl./af¡NG
FoRCE tO
SWrTCll
ANO INOICATING
MECHAN¡SMS
o
o
G
z
o
ó
o
F
U
o
ñ
ACIUÁÍOÊ
SPRING
OP:RATING
AE!-LOWS
AClUÂTOR
HOUSING
LOCK ÑUÎ
OFFSEIA0JUSTOA
NUf
swrvELJotNl
EULB
CÀPILLAFV
Figure
1
BULB AND
CAPILLARY
Material: Type
316
Stainless Steel
bulb
and
capillary
are standard.
Copper
capillary
is
available
upon
request.
INDICATING
TEMPERATURE
CONTROLLER
INSTALLATION
INSTRUCTIONS
PRINCIPTE
OF
OPERATION
Control
action
of these
mechanical indicating
temperature
controllers
is
provided
through the
principle
of lÍeuid volume
change, See Figure
1.
With
a
change in temperature,
the liquid
in the
sensing
bulb expands
and contracts,
causing
the
bellows to
actuate the
switchrng
mechanism.
Ambient
compensatron is
provided
by an expanda-
ble
push
rod
assembly mounted
on top
oi the
lever
arm which
moves the
pointer
and switching
mechanism.
Changes in
ambie:nt temperatures
through
a
range
of 0 to
150'F
(-
18 to
+
65"C)
expand or contract
this
push
rod assembly
to
provide
an
operating
balance for the
expansion and
contraction
of the
bellows
assembly
within
the
actuator
housing.
PROCESS
DIFFERENTIAL
The
process
differential
is minimum when the
narrow
differential
switch
ts used,
when
the fastest
responding
(smallest
diameter)bulb
is
used, when
the narrowest
scale range is
used, and
when
the
sensing
bulb is installed
in
a suitably designed
process
and in
a location which
is
close enough to
the heater
or
cooling
device to sense temperature
changes
quickly.
In
general,
it
is
difficult
to
predict
the operating
differential
of a
given
process.
The
differential
can
SPECtFtCAT|Ot{S
HOUSING
The
housing
(and
cover
assembly)
is made
of die
cast
aluminum with
a
gray
baked
enamel
finish.
It
is designed
to
meet
the
requirements
of
NEMA
Type
4 and
12
(lEC
IP65
and
IP62).
Neoprene
or cork-
neoprene
gaskets
seal
all
ports
and covers. Even
though
the
housing
is
watertight,
a separate cover
or
shield
is recommended
to
þrotect
the
controller
from
exposure
in
outdoor
applications.
!