Mid-West 130 Installation And Operating Instructions Manual

BULLETIN NO.IM130/02

(Supersedes IM130/01)

®

Model 130

Installation and Operating Instructions

INSPECTION

Before installation check nameplate on each
instrument against the receiving paperwork and the
intended application for correct part number,
materials, working pressure, dial range, etc. If
equipped with switches, check electrical rating,
type of enclosure, etc.Inspect for shipping damage.
If damaged, report it immediately.

NOTE - Before attempting repairs contact your

local Mid-West Representative or our
factory. Failure to do so will void any
warranty.

PR

ODUCT DESCRIPTION

The Model 130 is a differential pressure instrument
available as a switch, gauge, or both. See “Part
Numbering System”, (Fig. 2).

A flexible elastomer diaphragm and calibrated
range spring are moved by differential pressure. A

magnet, coupled with the diaphragm, transmits
motion through the wall of the pressure housing to
a follower magnet attached to an indicating pointer.
The rotation of the follower magnet causes the
pointer to track movement of internal magnet and
indicate differential on the dial scale.

When equipped with switches for Aluminum, Brass
or 316SS bodies only, a contact is made or broken
by the magnetic field of the internal magnet.

The diaphragm is totally supported upon reaching
full travel in either direction, providing full over­range protection to rated working pressure.

INST

ALLATION

Model 130 is calibrated and tested prior to
shipment and is ready for immediate installation.
Use of the following installation procedures should
eliminate potential damage and provide optimum
trouble-free operation.

Mid-West

Instrument

NOTE - It is highly recommended that a three

valve manifold be installed in the
instrumentation loop to minimize
possible damage during pressurization.

1. CONNECTIONS

Model 130 P is provided with 1/4" compression
tube fittings, one low and one high, on the top
and bottom of gauge body.

Model 130 A, B, H, S, is provided with dual 1/4"
FNPT connections top and bottom as standard.
One pair of high and low pressure ports is for
process connections. The other pair is plugged or
used as drain/bleed connections.

Ports are identified for high and low pressure. Be
sure to plumb to proper connections on system.
Improper connection will not damage instrument
but it will not function properly.

Flexible tubing is recommended to minimize effect
of any vibration that may exist.

When attaching connections to the 130 P, care
must be taken to prev ent o v er-tightening which ma y
result in stripping threads and/or cracking ports. In
order to prevent this, use a suitable wrench to hold
the factory supplied fitting in place while tightening,
sometimes called “double wrenching”.

2. INSTRUMENT LOCATION

On liquid service, the instrument should be
mounted below the process connections to
facilitate self-bleeding.On gas service, it should be
located above the process connections to promote
self-draining. If the process contains particulates, a
“pigtail” loop or drop leg (manometer “U-tube”
configuration) in the tubing will minimize the
possibility of it migrating into the instrument.

NOTE - On liquid applications, unequal liquid

heads on high or low side will result in
an inaccurate differential pressure
indication.

3. PANEL MOUNTING

The Model 130 is designed for mounting through
the front of the instrument panel and is provided
with a panel mount kit, consisting of (4) panel
mounting studs/nuts.

Make cutouts as indicated in (Fig. 1). Insert (4) panel
mounting studs, finger tight, into metal inserts located
in the rear of the bezel.

Insert gauge through the panel, aligning panel
mounting studs with holes in the panel. Install #8­32 nuts onto studs and tighten securely.

4. PIPE MOUNTING

If specified, your Model 130 will have a pipe mount
kit installed. This provides for mounting on a 2"
vertical or horizontal pipe. See (Fig. 1).

5. ELECTRICAL - See Mid-West Bulletin
IMELEC130/latest

TR

OUBLE SHOOTING

1. Gauge does not indicate differential.

A. Check for proper hook up, high to “hi” and

low to “lo”.

B. Make certain block valves are open and, if

using a 3-valve manifold, that the equalizer
(balance) valve is closed.

C. If A & B check out, loosen high pressure line

to determine if there is pressure to
instrument.

D. If there is pressure to instrument, check to

determine that there is differential across the
unit being monitored.If so, contact factory for
assistance and/or an “RGA” (return goods
authorization) number to return instrument
for repair or replacement.