Ruelco MP-2 Operation Manual

“MP-2”
MANUAL RELAY
MODEL 10A1
OPERATION MANUAL
OMP # 10A1 12/00

I. PRINCIPLE OF OPERATION

The Ruelco “MP-2” relay is a pilot operated
manual relay. It is a three (3) way, normally
closed valve with a palm knob for relay
position indication and manual operation. In
the closed position, pneumatic or hydraulic
pressure coming into the “Inlet” port is
locked from the “Outlet” port by the upper
shaft o-ring. The spring keeps the spool in
the down or closed position. The valve is
opened by manually pulling the palm knob
outward, thus moving the shaft assembly
upward. The detent pin is then pushed “In”
to lock the relay open until a pneumatic
signal is applied to the pilot cap of the relay.
This pneumatic pressure acting on the
piston causes the detent pin to drop “Out” of
the locked position. When the relay is in the
open position, it causes the middle o-ring to
engage the body seal bore and the upper o­ring to disengage from the body seal bore
respectively. Supply pressure at the “Inlet”
port may then flow through the body to the
“Outlet” port.

When the pneumatic signal is removed from
the pilot cap, the spring moves the shaft
assembly downward. This causes the upper
o-ring to engage the body seal bore and the
middle o-ring to disengage the body seal
bore respectively. With the supply pressure
blocked, pressure will flow from the “Outlet”
port and exit through the “Vent” port. The
relay may also be closed manually by
pushing the palm knob inward.

II. INSTALLATION

The “MP-2” can be mounted either
vertically, horizontally, panel mounted (with
optional panel mount nut), or supported by
piping from any of its ports. If it is supported

to prevent the fitting from breaking off in the
relay body should the relay be inadvertently
struck.

Proper pipe thread sealant should be used
on any pipe fittings threaded into the relay
ports. If stainless steel fittings are used, a
sealant that will prevent galling is required.
Supply gas or hydraulic fluid flowing through
the relay should be free of large dirt
particles. If compressed air is used, it does
not have to be lubricated. If natural gas is
used, it should contain as little condensate
as possible. This will extend the life of the
seals.

If the relay is going to be installed in a
location where the stem will be exposed to
excessive paint, sand, drilling fluids, etc.,
the use of the optional stem protector is
recommended. The stem protector does not
affect the operation of the relay and will
prevent the relay from jamming should the
exposed portion of the shaft accumulate
excessive trash or debris.

III. DISASSEMBLY (REFER TO SPEC.

SHEET 10A1)

Tools required are as follows:

• 7/16” open end wrench or
suitable adjustable wrench

• 1” open end wrench or suitable
adjustable wrench

• 7/8” open end wrench or suitable
adjustable wrench and flat blade
screw driver (for removal of
optional stem protector)

• 1/8” Allen wrench (for complete
disassembly)

by piping, care should be taken that the
strength of the pipe fittings used is adequate

A. PARTIAL DISASSEMBLY

1. To replace the three (3) shaft
o-rings (Item 9) and the piston
seal (Item 13), the relay does
not have to be completely
disassembled. The upper seal
(Item 8) may not have to be
replaced as often as the other
moving seals.

2. Place the 7/16” wrench on

the lock nut and rotate it
clockwise while holding the
knob (Item 1) until the knob
is loose. Rotate the knob
counterclockwise and
remove it from the shaft
subassembly (Item 10). If the
optional stem protector is
installed, pull the relay knob
outward until the flat on the
seal washer (Item 7) is
visible. Use the 7/8” wrench
to rotate the seal washer
clockwise until the knob is
loose. Remove the knob and
seal washer simultaneously
(rotate counterclockwise).

3. Remove any piping

connections from the base
(Item 15) that would prevent
it from being removed from
the body (Item 11). Using the
1” wrench, rotate the base
counterclockwise until it is off
the body.

4. Push the shaft subassembly

through the valve body and

IV. REPAIR AND ASSEMBLY

1. Remove the piston and shaft seals
slide the spring (Item 12) off
the relay shaft.

5. The seals on the shaft may

2. Using an appropriate safety solvent,
now be replaced as per
instructions given in the
repair section of this manual.

3. Inspect the shaft assembly for any

B. FULL DISASSEMBLY

1. Follow the procedures stated
under partial disassembly. If
the relay is panel mounted, it
is not necessary to remove
the relay from the panel, but
it is recommended so that
adequate inspection and
cleaning of all parts may be
performed.

2. Using the 1/8” Allen wrench,
rotate the set screws
counterclockwise
approximately four (4) turns.
The screws do not have to
be completely removed.

3. Pull the head (Item 7)
outward from the body. If the
relay is panel mounted, pull
the body from the head. If the
head does not come
completely out, it may be
necessary to loosen the set
screws more.

4. To remove the stem
protector housing (Item 16) fs
installed, use the flat blade
screw driver and rotate the
screws (Item 4)
counterclockwise.

5. The relay is now ready to be
cleaned and repaired.

from the shaft and the upper seal
from the body.

clean all parts.

major damage such as burrs, nicks
on the upper part where the upper
seal (Item 8) contacts its. Also
inspect it for straightness. Replace
the shaft assembly is damaged.

4. Examine the relay body and head
bores for any damage such as burrs,
nicks, etc. Replace any damaged
pieces.

5. Replacement seals from a Ruelco
product repair kit are required for
proper relay performance. It is
recommended that all seals be
lubricated before and after
installation with a high quality
silicone base grease.

6. Install the upper seal into the valve
body. NOTE: This is a cup type seal.
The inside of the cup should be
facing down and toward the valve
body as shown.

7. Install the head into the upper body.
The panel mount threads should
almost touch the body. If not,
remove the head and verify that
neither the set screws or any debris
are obstructing the correct
installation.

8. Using the Allen wrench, rotate the
three (3) set screws clockwise until
lightly tightened. Tighten all three (3)
firmly afterwards.

9. Install the piston seal onto the shaft
subassembly. NOTE: This is a cup
type seal. The inside of the cup
should be facing toward the bottom
of the shaft subassembly as shown.
Be sure that the inside lip of the seal
is completely pushed into the piston
groove.

10. Lubricate the shaft o-rings and install
on the shaft subassembly.

11. Lightly lubricate the large bore in the
relay body.

12. Slide the spring over the shaft
subassembly and slide the shaft into
the relay body.

13. Lubricate the base o-ring (Item 14)
and install into the valve body.

14. Rotate the base clockwise onto the
body and use the 1” wrench to
tighten.

15. If a stem protector is to be used,
locate the holes in the protector
body over the threaded holes in the
head. Insert the two (2) screws and
rotate them clockwise to tighten.

16. Thread the lock nut over the shaft
subassembly until it reaches the last
thread. Do not tighten. Rotate the
knob over the shaft thread until it
touches the lock nut. Hold the knob
and turn the lock nut
counterclockwise with the 7/16”
wrench until firmly tightened.

17. To install the stem protector washer
and the knob, thread the washer as
far down onto the shaft as possible.
Screw the knob onto the exposed
threads above the washer, but do
not tighten. Pull the relay shaft fully
outward and thread the protector
washer until it stops. NOTE: The
protector seal should now be
completely inside the protector
housing. Release the relay knob and
allow the shaft subassembly to
retract. Rotate the knob clockwise
until it stops. Pull the knob outward
again and use the 7/8” wrench to
turn the protector washer
counterclockwise until tight.

V. RECOMMENDED MAINTENANCE

Procedure and Interval

Operate Manually – Every thirty (30) days.

Disassemble, inspect and lubricate – Yearly
or as required.

Replace all seals – Every two (2) years or
as required.