Ruelco 30C2 User manual

3-WAY
FLEX LEVEL
LIQUID LEVEL SWITCH
OPERATION MANUAL
OMP# LS-3 – 5/19
1.0 INTRODUCTION
The Ruelco Model 30C2 (2” NPT
Mount)/31C2 (Flange Mount) 3-way
pneumatic liquid level switch is
typically mounted directly into a tank or
vessel or in an optional external cage
(See Figures 1,2). Horizontal or hang
down displacer elements are available.
This displacer operates a pneumatic
valve when a liquid in a tank or a
pressurized vessel reaches a
predetermined level. The operation
mode, as a high or a low level sensor, is
selected by rotating the valve body 180
degrees.
FIG. 1
TYPICAL MOUNTING OF MODEL 30C2
LEVEL SWITCHES
FIG. 2
MODEL 30C2 SHOWN IN
MODEL 3C01 EXTERNAL CAGE
2.0 OPERATION (See Fig. 3)
When in the non-tripped condition, the
3-way pneumatic valve is configured as
a normally open valve when set for high
level detection and as a normally closed
valve when set for low level detection.
When used as a high level sensor, the
valve will allow air flow from inlet to
outlet when the liquid is below the
displacer. When liquid contacts the
displacer, the valve will block the inlet
pressure and vent the outlet pressure.
When used as a low level sensor, the
valve will allow air flow from inlet to
outlet when the liquid is above the
displacer. When liquid no longer
contacts the displacer, the valve will
block the inlet pressure and vent the
outlet pressure.
Because of the balanced design of the
valve, variations in instrument pressure
from 5 to 50 PSI will have little effect
on level switch performance.
The switch senses a change in the
buoyancy of a displacer assembly inside
a pressurized or unpressurized vessel.
To transmit the buoyancy change, a
pivoting action is used. The I.D. of the
cone contacts the pivot attached to the
push rod and valve body. The o-ring
(provides a pressure tight seal between
the body and the shaft of the cone
protruding through the o-ring. Pressure
in the vessel, if any, acting on the shaft
of the cone, forces the cone against the
pivot point on the valve body. The
position of this point, at the center of the
o-ring, allows the displacer assembly to
move up or down.

2
2.1 HIGH LEVEL OPERATION
(NORMALLY OPEN)
As the liquid level rises and begins to
cover the displacer assembly, the
buoyancy in the liquid reduces the
counterclockwise rotational force on the
cone. At some point, the spring will
exert a greater clockwise rotational force
and cause the cone to push the valve
stem downward, and act on the push rod
and 3-way valve. This allows the
pressure present at the outlet to vent
through the weep holes in the valve
body while blocking the inlet pressure.
2.2 LOW LEVEL OPERATION
(NORMALLY CLOSED)
As the liquid level falls and begins to
uncover the displacer assembly, its
buoyancy in the liquid increases the
counterclockwise rotational force on the
cone. At some point, the displacer will
exert a greater clockwise rotational force
and cause the cone to push the valve
stem upward, and act on the push rod
and 3-way valve. This allows the
pressure present at the outlet to vent
through the weep holes in the valve
body while blocking the inlet pressure.
NOTE: THE VALVE CAN BE USED
WITH OPPOSITE FUNCTION IF
ROTATED 180 DEG.
3.0 INSTALLATION
3.1 EXTERNAL CAGE TO VESSEL
It is suggested that the level switch be
installed in an external cage for
maintenance and testing purposes. One
recommended piping system for
mounting an external cage to a vessel is
shown in Figure 1. The valves above
and below the cage are required for
testing and maintenance purposes.
If a cage with butt weld connections is
used, the level switch should be
removed from the cage before welding.
This will prevent weld sparks from
damaging the displacer assembly.
Remove the switch from the cage as per
instructions in Paragraphs 5.2.1
through 5.2.2 of the FULL
DISASSEMBLY section of this manual.
After welding, install the level switch as
per instructions in Section 3.2,
INSTALLING LEVEL SWITCH IN
CAGE.
If the cage has threaded or flanged
process connections, the level switch
does not have to be removed before
mounting the switch to the vessel. Cages
with 1” NPT process connections may
be installed on the vessel with 1”, ¾”
or ½” O.D. piping.
CAUTION: Be sure the pressure
rating of all valves, pipe and pipe
fittings meets or exceeds the working
pressure of the vessel on which they
are to be installed. Adequate support
for long pipe runs should be provided
to prevent excessive vibrations of the
level switch.
It is recommended that external cages be
installed with the process connections as
close to vertical and the cage length as
close to horizontal as possible. This will
insure the proper liquid flow into and
out of the cage.
3.2 LEVEL SWITCH INSTALLATION
Before installing a level switch into an
external cage or mating flange, verify
that level switch is set up or the
operation required (i.e., high or low
liquid level detection). See Section 4.0,
CHANGING MODE OF OPERATION
and Figure 5. NOTE: When direct
mounting a level switch to a tank or
vessel, verify that the end displacer
assembly will be at least ½” (13mm)

3
longer than the 2” connection on which
it is being installed. (See Figure 4).
TOOLS REQUIRED: A 2.125” open
end wrench or a suitable adjustable
wrench or pipe wrench.
3.2.1 Clean any dirt or debris from the 2”
NPT pipe threads and the external cage
(if any are being utilized).
3.2.2 Apply Teflon tape or other thread
sealing compound to the 2” NPT threads
on the level switch.
3.2.3 Apply an anti-galling compound to the
2” NPT female thread into which the
switch is installed.
3.2.4 Screw the level switch into the
mounting thread and tighten with the
wrench. When tight the spring cap must
be up as shown in Fig. 5.
FIG. 3

3
CAUTION: If using a pipe wrench, do
not allow the wrench jaws to contact the
spring cap. Wrench forces may damage
the cap and prevent the switch from
operating properly.
NOTE: THE SPRING CAP MUST ALWAYS
BE IN THE VERTICAL POSITION AS
SHOWN IN FIG. 5 FOR THE “FLEX LEVEL”
SWITCH TO OPERATE PROPERLY.
FIG. 4
TYPICAL DIRECT MOUNTING
4.0 CHANGING MODE OF
OPERATION
TOOLS REQUIRED: 3/16” Allen Wrench
The level switch can be changed from high level
detection to low level detection very easily. If
the level switch is installed into a pressurized
cage or vessel, the pressure does not have to be
removed, but the caution in Section 4.2 should
be followed closely. Fig. 5 shows the proper
orientation of the level switch function markings
for high and low level operation.
FIG. 5
4.1 UNPRESSURIZED CAGE
OR VESSEL
4.1.1 Verify that no pressure is
present in the cage or vessel. If
this cannot be verified, follow
instructions in Section 4.2
PRESSURIZED CAGE OR
VESSEL.
4.1.2 Block and bleed the instrument
pressure from the inlet. Remove
any instrument tubing connected
to the inlet.
4.1.3 With the 3/16” Allen wrench,
remove the four hex socket head
cap screws. Rotate the valve
body 180 degrees to change the
mode of operation from high to
low or from low to high as
desired. See Fig. 5 for proper
valve body orientation.
4.1.4 Replace the four hex socket cap
screws and tighten.
4.1.5 Connect the instrument supply
if it was disconnected.
4.2 PRESSURIZED CAGE OR VESSEL
4.2.1 Block and bleed the instrument
pressure from inlet. Remove any
instrument tubing connected to
the inlet.
4.2.2 Use a 3/16” Allen wrench and
remove two of the hex socket
head cap screws that are
diagonally apart. Replace the
two hex socket head cap screws
just removed with two ¼”-20
screws or bolts that are 1-1/4’ to
1-1/2” long. These serve as a
safety stop in the event the level
switch has received unknown
damage. Rotate the remaining
two screws one turn at a time,
alternating between the two.
The process pressure acting on

4
the end of the cone that is
protruding through the body
will move the valve body
outward as the two screws are
turned. When the valve body
has stopped moving, remove the
four screws completely. Rotate
the valve body 180 degrees to
change the mode of operation
from high to low or from low to
high as desired. See Fig. 5 for
proper valve body orientation.
CAUTION: THE VALVE BODY SHOULD
MOVE OUTWARD 1/16” AND STOP AS
THE DISPLACER ASSEMBLY
CONTACTS THE BODY. IF THE
PROCESS PRESSURE IS STILL
EXERTING A FORCE ON THE VALVE
BODY AFTER 1-1/2 TURNS, THEN STOP
TURNING THE TWO SCREWS. THE UNIT
MAY HAVE DAMAGE THAT WILL
ALLOW THE CONE TO DISENGAGE
THE O-RING AND THE PROCESS
PRESSURE AND MEDIUM WILL ESCAPE
THROUGH THE BODY. THE PROCESS
PRESSURE WILL HAVE TO BE
REMOVED FROM THE CAGE OR
VESSEL BEFORE ANY FURTHER
DISASSEMBLY IS POSSIBLE.
4.2.3 Replace the four hex socket head cap
screws and tighten.
4.2.4 Connect the instrument supply if it was
disconnected.
5.0 DISASSEMBLY (SEE FIG. 1 and 3)
TOOLS REQUIRED:
7/16” open end wrench or adjustable wrench
5/8” open end wrench or adjustable wrench
3/16” Allen wrench
1/8” Allen wrench
Needle nose pliers
Pliers
O-ring pick or small screwdriver
Large adjustable wrench or pipe wrench
5.1 PARTIAL DISASSEMBLY
(3-WAY POPPET VALVE REPAIR)
CAUTION: ONLY THE VALVE BODY
CAN BE REMOVED FROM THE LEVEL
SWITCH UNIT WITHOUT
DEPRESSURIZING THE CAGE OR
VESSEL. ANY FURTHER DISASSEMBLY
WITH PRESSURE PRESENT ON THE
CAGE OR VESSEL WILL RESULT IN
SEVERE PERSONAL INJURY OR
DAMAGE TO EQUIPMENT.
5.1.1 It is not necessary to completely
disassembly the unit to remove the valve
body from the level switch. It is not
required to depressurize the cage or the
vessel the level switch is installed in, but
it is recommended to do so if possible.
5.1.2 To remove the valve body when the
level switch is installed in a pressurized
cage or vessel, follow instructions in
Paragraph 5.1.3. If the cage or vessel is
not pressurized, use a 3/16” Allen
wrench and remove the four hex socket
head cap screws.
5.1.3 Use a 1/8” Allen wrench and loosen the
three hex socket head set screws that are
on the outside of the 3-way valve. This
will allow for the removal of the 3-way
valve from the level switch.
5.1.4 Note the orientation of the Push Rod and
ensure this is not lost.
CAUTION: THE VALVE BODY SHOULD
MOVE OUTWARD 1/16” AND STOP AS
THE DISPLACER ASSEMBLY
CONTACTS THE BODY. IF THE
PROCESS PRESSURE IS STILL
EXERTING A FORCE ON THE VALVE
BODY AFTER 1-1/2 TURNS, THEN STOP
TURNING THE TWO SCREWS. THE UNIT
MAY HAVE DAMAGE THAT WILL
ALLOW THE CONE TO DISENGAGE
THE O-RING (4) AND THE PROCESS
PRESSURE AND MEDIUM WILL ESCAPE
THROUGH THE BODY. THE PROCESS

5
PRESSURE WILL HAVE TO BE
REMOVED FROM THE CAGE OR
VESSEL BEFORE ANY FURTHER
DISASSEMBLY IS POSSIBLE.
5.1.5 Loosen the retainer and the stinger can
be accessed.
5.1.6 The seals may be replaced as per
instructions in the Section 6.0 REPAIR
and ASSEMBLY.
5.2 FULL DISASSEMBLY
CAUTION: ALL PRESSURE MUST BE
REMOVED FROM THE CAGE OR
VESSEL BEFORE FULL DISASSEMBLY
CAN BE PERFORMED. FAILURE TO
REMOVE THE PRESSURE MAY RESULT
IN PERSONAL INJURY OR DAMAGE TO
EQUIPMENT.
5.2.1 Verify that all pressure has been
removed from the cage or vessel and
drain the liquid to a level below the
level switch.
5.2.2 Using the large adjustable wrench or
pipe wrench, remove the level switch
from the cage or vessel.
5.2.3 Hold the float rod (2) with the pliers and
rotate it counterclockwise to remove it
from the level switch.
5.2.4 Normally it is not necessary to remove
the displacer or float assembly from the
float rod. If required, loosen the lock nut
(18) and unthread the displacer or float
assembly from the float rod.
5.2.5 Follow instructions in Section 5.1
PARTIAL DISASSEMBLY to remove
and disassembly the valve body.
5.2.6 Use the 5/8” wrench and rotate the
spring cap counterclockwise to remove
it from the body. Care should be taken
not to lose the spring and spring guide.
5.2.7 Using pliers to grip the O.D. of the
pivot, rotate it counterclockwise to
unthread it from the valve body.
5.2.8 Push the threaded end of the cone
through the body.
5.2.9 Using an o-ring pick or small
screwdriver, remove the o-ring from the
body.
6.0 REPAIR AND ASSEMBLY:
REFER TO DATA SHEET FOR
REPLACEMENT PART NUMBERS
TOOLS REQUIRED:
7/16” open end wrench or adjustable wrench
5/8” open end wrench or adjustable wrench
3/16” Allen wrench
Needle nose pliers
Safety solvent
Silicone based o-ring lubricant
Large adjustable wrench or pipe wrench
6.1 Using appropriate safety solvent, clean
all parts.
6.2 Inspect the I.D. of the valve retainer and
the O.D. of the valve stem for nicks and
gouges. Replace any worn or damaged
parts.
6.3 The point of the pivot should not be
flattened or bent. The sealing surfaces
(side and bottom) for the seat o-ring
should be free of pits and gouges.
Replace if necessary.
6.4 If the level switch has a stainless steel
displacer assembly, it should be free of
dents, cracks or holes.
6.5 Lubricate all seals from the repair kit
with a silicone-based lubricant.
6.6 Install the valve seat o-ring into the
valve body and push it completely to the
bottom of the receptacle.

6
6.7 Install the valve stem o-ring and the
valve retainer o-ring. Lubricate the
valve stem o-ring and insert the valve
stem into the valve retainer.
6.8 Using the needle nose pliers, install the
valve retainer with valve stem installed
into the valve body and tighten.
6.9 Thread the pivot onto the valve body
and firmly tighten with pliers.
6.10 Install the body o-ring into the body.
6.11 Lubricate the shaft and the threads on
the threaded end of the cone. Install the
cone into the body by turning clockwise
and pushing gently.
6.12 Align the body tabs with the slots in the
cone and slide the valve body into the
level switch body.
6.13 Arrange the valve body in the correct
position for the desired high or low
operation. See Fig. 5. Install and tighten
the four hex socket head cap screws.
6.14 Thread the float rod onto the cone and
tighten securely with pliers. If the
displacer assembly was removed,
reinstall and tighten the lock nut
securely.
6.15 Insert the spring and spring guide into
the spring cap. Install the spring cap into
the body and tighten.
6.16 Replace the level switch assembly into
the cage or mating flange as per
instructions in Section 3
INSTALLATION.
7.0 RECOMMENDED MAINTENANCE
PROCEDURE INTERVAL
Test switch in place with every 30 days
Process liquids to check
For proper operation.
Clean vent ports of debris every 30 days
Replace body seal (4) as required
.

7
TROUBLESHOOTING
PROBLEM
PROBABLE CAUSE
RECOMMENDED ACTION
1) Level switch does not
function
A) Debris blocking the vent port
Clean vent port and test switch
B) Trash on inside of the cone
(21).
Remove the valve body (9) per
procedures in Section 5.
1 and
clean cone I.D.
C) Poppet valve (18) sticking
Follow procedures in Sections
5.1 and 6.0 to disasse
mble and
replace the seals (19)
D) Inlet port plugged.
Disconnect all instrument tubing
and clean inlet port. Clean
instrumentation system filters.
E) Connecting tubing plugged.
Remove and clean or replace
instrument tubing. Clean
instrumentation system filters.
F) Trash accumulation on
displacer assembly (1).
Remove switch from vessel or
cage per procedures in Section
5.2
G) “FLEX-LEVEL” not installed
properly.
Use instructions given in Section
3.0 to properly install the switch.
2) Liquid or gas leakage from
vent port.
A) Poppet valve seals (19)
damaged or worn.
Follow procedures in Section 5.1
a
nd 6.0 to disassemble and
replace the seals (19).
B) Body seal (4) damaged or
worn
Replace body seal (4) per
instruct
ions in Section 5.0 and
6.0.
CONSULT THE FACTORY OR AN AUTHORIZED DEALER IF THE SWITCH CANNOT BE
REPAIRED BY FOLLOWING THESE PROCEDURES.