Matheson PM-24 User manual

MINT-0240 rev C
Model PM-24
PRESSURE MONITOR
Instructions
READ AND COMPLY WITH THESE INSTRUCTIONS BEFORE
INSTALLING, OPERATING, OR SERVICING

Table of Contents
I. SERVICE ........................................................................................................1
II. LIMITED WARRANTY ...................................................................................2
III. USER RESPONSIBILITY.................................................................................3
IV. SAFETY PRECAUTIONS................................................................................4
V. GENERAL DESCRIPTION ...............................................................................5
VI. INSTALLATION............................................................................................6
VII. OPERATING INSTRUCTIONS.......................................................................7
VIII. TROUBLE SHOOTING ................................................................................8
IX. DRAWINGS...............................................................................................10

1
I. SERVICE
General Service
A unit which is not functioning in a normal manner should be removed from service until
such time that repairs or replacement can be made. Upon completion of repair, full
testing should be performed to assure the user that the unit has been returned to its
original operating parameters. MATHESON can repair or replace equipment. To
arrange for repair or replacement service, call 1-800-828-4313 and ask for the Warranty
Administrator. No product will be received by MATHESON without indication of
gas service and without proper return material authorization provided by the
warranty administrator. (All repairs must be made by MATHESON or an
assigned and approved facility to maintain any warranties or guarantees).
If the unit is under an applicable warranty, return the unit to MATHESON for repair or
replacement. To arrange for warranty service, call 1-800-828-4313 and ask for the
Warranty Administrator. No product will be received by MATHESON without
indication of gas service and without proper return material authorization provided
by the warranty administrator.
If advised by the Warranty Administrator to return the product to MATHESON, prepare
the product for shipment and write, in large lettering the RMA Number assigned by the
Warranty Administrator on the outside of the box. Also, if required by the Warranty
Administrator, supply the completed RMA form with the product. Make sure that the
product is adequately packaged, in the original shipping container if possible, and
shipped prepaid (MATHESON will not accept COD freight) with a description of the
observed deficiency to the attention of the:
Warranty Administrator
MATHESON
166 Keystone Drive
Montgomeryville, PA 18936
The user is expected to periodically inspect the product for leaks, loose or worn parts,
broken or non-functioning components and to address those situations immediately. If
the user would require verbal assistance in ascertaining the potential of a problem with
any MATHESON product, contact the local MATHESON branch for assistance or your
MATHESON Sales Representative.

2
II. LIMITED WARRANTY
This equipment is sold by MATHESON under the warranties set forth in the following
paragraphs. Such warranties are extended only with respect to the purchase of this
equipment directly from MATHESON or MATHESON's Authorized Agent as new
merchandise and are extended to the first Buyer thereof other for than the purpose of
resale.
For a period of one year from date of original delivery (ninety days in corrosive service)
to Buyer or to Buyer's order, this equipment, is warranted to be free from functional
defects in materials and workmanship and to conform to the description of this equipment
contained in this manual and any accompanying labels and/or inserts, provided that this
equipment is properly operated under the conditions of normal use and that regular and
periodic maintenance and service is performed or replacements are made in accordance
with the instructions provided. Expendable parts of this equipment are similarly
warranted to be free from functional defects in materials and workmanship and to
conform to the description of this equipment contained in this manual and any
accompanying labels and/or inserts. The foregoing warranties shall not apply if the
equipment has been repaired other than by MATHESON or a service facility designated
by MATHESON, or if this equipment has not been operated and maintained in
accordance with written instructions provided by MATHESON, or has been altered by
anyone other than MATHESON, or if the equipment has been subject to abuse, misuse,
negligence or accident.
MATHESON's sole and exclusive obligation and the Buyer's sole and exclusive remedy
under the above warranties is limited to repairing or replacing, free of charge, at
MATHESON's sole discretion, the equipment or part which is telephonically reported to
be a problem to the local MATHESON Branch Location, and which if so advised, is
returned with a written statement of the observed deficiency, not later than seven days
after the expiration of the applicable warranty, to the MATHESON Gas Equipment
Technology Center during normal business hours, transportation charges prepaid, and
which, upon examination, is found to comply with the above warranties. The Buyer
shall pay for return trip transportation charges for the equipment or part.
MATHESON shall not be otherwise liable for any damages including but not
limited to incidental damages, consequential damages, or special damages, whether
such damages result from negligence, breach of warranty or otherwise.
There are no express or implied warranties that extend beyond the warranties
hereinabove set forth. MATHESON makes no warranty of merchantability or
fitness for a particular purpose with respect to the equipment or parts thereof.
Acceptance of the equipment by the final buyer indicates the final buyer’s
acceptance of all warranties and limitations set forth above.

3
III. USER RESPONSIBILITY
This equipment will perform in conformity with the description thereof contained in this
manual and accompanying labels and/or inserts when installed, operated, maintained and
repaired in accordance with the instructions provided. This equipment must be checked
periodically, with the frequency of such inspections depending upon the scope of use.
Damaged, worn or contaminated equipment should not be used. Parts that are broken,
missing, plainly worn, distorted or contaminated should be replaced immediately.
Should such repair or replacement become necessary, MATHESON recommends that a
telephonic or written request for service advice be made to the MATHESON Equipment
Engineering Group in Montgomeryville, Pennsylvania or to the nearest MATHESON
branch location.
This equipment or any of its parts should not be altered without the prior written approval
of MATHESON Equipment Engineering Group. The user of this equipment shall have
the sole responsibility for any malfunction, which results from improper use, faulty
maintenance, damage, improper repair or alteration by anyone other than MATHESON
or a service facility designated by MATHESON. Further, the ultimate user of the
equipment is responsible for the training and safe operation of the equipment by
personnel in his/her employ.

4
IV. SAFETY PRECAUTIONS
1. Many specialty gases are hazardous in nature. It is important that the User of the
equipment carefully review the hazards associated with the gas to be used with the
associated equipment. NOTE: refer to the MSDS that was shipped with the gas,
as to the specific hazards associated with that gas. Also, refer to all applicable
inserts contained with the equipment for additional precautions and operating
instructions.
2. Before using any equipment on toxic, corrosive, pyrophoric, flammable or other
Hazardous gas, test the leak integrity of the equipment using an inert gas. Make
certain that the equipment purchased is suitable for the application intended.
3. Make certain that the equipment delivered to the User conforms to the specifications
of the User. The User is responsible for selecting equipment compatible with gases
that are to be used, physical parameters of operation and performance, and normal
material compatibilities. Selection information can be found in MATHESON
Catalogs, MATHESON Tech Briefs and in the MATHESON Gas Data Book. In
addition, any MATHESON representative would be pleased to aid in the selection of
specific equipment.
4. Before installation of the equipment onto the cylinder of compressed or liquefied
gas, carefully inspect the equipment for visible signs of damage or contamination.
Close attention should be given to all exposed and connecting threads, where there
should be no visible signs of wear or abuse. Also examine the equipment for any
loose parts outside of those that must swivel for connection to the gas cylinder or
Outlet lines. Examine the inlet and outlet of the equipment for signs of
contamination with dirt, grease or any other foreign material. If any foreign
materials are present and cannot be removed from the equipment easily with a cloth,
or if the threads on any components of the equipment appear to be abused as
indicated above, or any of the components appear to be loose, return the equipment
immediately to MATHESON’s Montgomeryville, Pennsylvania facility for service.
5. Before installation of the equipment onto a compressed or liquefied gas cylinder,
move the cylinder(s) to the point of use and secure the cylinder before removing
the cylinder’s outer cap. Check the cylinder valve as in step 4 for possible
contamination and defective or loose parts. If for any reason the cylinder appears
to be faulty as noted here, return the outer cap to the top of the cylinder, and
remove the cylinder from the work area. Call the supplier of the cylinder for
immediate pick-up.
6. When using any hazardous gas, the cylinder should be placed under an exhaust hood
or in a suitable safety enclosure. Before connection of the gas equipment to the gas
cylinder, make certain that the CGA connection on the cylinder matches the CGA
connection on the equipment. CGA connections are fitted to the equipment to
prevent its use with any incompatible gases.
WARNING: ANY ALTERATIONS TO THE EQUIPMENT, TO ALLOW ITS USE
WITH GASES OTHER THAN THE GAS TYPE FOR WHICH IT WAS
ORDERED, CAN BE EXTREMELY DANGEROUS AND SHOULD NOT BE
ATTEMPTED. CONSULT MATHESON’S ENGINEERING TECHNICAL
SERVICES GROUP BEFORE ATTEMPTING ANY ALTERATIONS TO GAS
EQUIPMENT.

5
V. GENERAL DESCRIPTION
The MATHESON Pressure Monitor, Model PM-24, was designed as a method of
ensuring uninterrupted gas supplies, when used in conjunction with MATHESON
switchover manifold systems.
The unit consists of two components:
1. An annunciator with audio/visual alarm
2. The 120 VAC, 60HZ power adapter with 15VDC output
Amphenol back shells, contact pins and connectors are also supplied to connect dry
contact switch wires to the Left and Right input connectors.
Each unit comes complete with green (RUN) indicator lights for each channel to indicate
a pressure level above the IPS set point, red (PRESSURE LOW) indicator lights for each
channel to indicate low pressure or empty status, a common horn for audible alarm, and
an ALARM SILENCE/ RESET button.
An amphenol connector, back shell and 4 contact pins are supplied for the output
connection on the bottom of the case. The output can be wired for individual left and
right remote outputs, or as a common output. See FIGURE-2 for details.
The enclosure is 14 gauge steel, painted, and dustproof. The front is supplied with a 10-
mil Lexan label, which may be wiped down with warm soapy water. The enclosure has
attached brackets for wall mounting. See FIGURE-2 for details.

6
VI. INSTALLATION
1. Mount the enclosure firmly to the wall or unistrut. It is the installer’s responsibility
to select the correct mounting hardware, depending on the mounting surface.
WARNING: This enclosure is not rated and should not be used in a
hazardous area where flammable gases or vapors may be present.
NOTE: This enclosure should be mounted within five feet of a 120 VAC
outlet.
2. Crimp the wires from the Indicating Pressure Switches (IPS) from each side of the
switchover manifold, using pins supplied with the unit. Insert the wire through the
back shell, and then insert the pins into the housing connector (also supplied with
the unit). Connect the left IPS to the left side connector on the PM-24, marked INP-
L and the right side IPS to the connector marked INP-R on the bottom of the unit.
Refer to FIGURE-1.
3. The connector marked OUTPUT on the unit is for monitoring the output from a remote
location. It is a Form C, dry contact, N.O. Pins 1 & 2 are for output - Left, and 3 & 4
are for output-Right. When using as a common output, simply jump pins 2 & 3, and
pins 1 & 4 will provide a common output. Refer to FIGURE-2.

7
VII. OPERATING INSTRUCTIONS
1. Push the power adapter plug into the jack on the left side of the unit.
2. Plug the power supply into a suitable 120 VAC receptacle.
3. All the LEDs will blink momentarily, and the alarm will beep. The operator can
verify all the LEDs and the alarm are working properly.
4. With the unit powered up, the front panel should display one of the following states:
a. If both sides of the switchover manifold system are below the IPS set
point for ten (10) seconds, the red lights on both sides will be lit, and the
audible alarm should sound. Pressing the ALARM SILENCE button on
the front of the unit will silence the audible alarm, but will not reset the
lights to green.
b. If both sides of the switchover manifold system are above the IPS set
point, the green lights on both sides will be lit, and the audible alarm will
not sound.
c. If one side of the switchover manifold system is below the IPS set point
for ten (10) seconds, the red light on that low side will be lit, and the
audible alarm will sound. The other side above the set point will display
the green light. Pressing the ALARM SILENCE button on the front of the
unit will silence the audible alarm, but will not reset the light to green.
5. The PM-24 lights will reset from red to green only when the pressure is above the
set point of the IPS and the red pushbutton, (Hold to Reset), is held in for three (3)
seconds.
6. Note that the audible alarm will not sound for another low pressure red light after
the first ALARM SILENCE button is pressed and its red light remains on. The
depleted cylinder should be changed when the first alarm sounds to prevent the
switchover system from running out of gas completely.

8
VIII. TROUBLE SHOOTING
Symptom
Probable Cause
Solution
No lights or audible alarm.
Power supply may not be
engaged into unit or wall
receptacle.
Internal Damage.
Remove and replace power.
All the LEDs should blink
and the alarm should beep.
If any of the LEDs don’t
blink or the alarm doesn’t
beep return to
MATHESON for repair.
Defective power supply.
If none of the LEDs and the
alarm doesn’t beep after
cycling, power check power
supply and replace if
necessary.
Unit lights up, but there is
no audible alarm with red
lights.
Defective circuit or
alarm buzzer.
Return to MATHESON for
repair.
Cylinder is above set
point, but red light stays
on, and there is an audible
alarm.
Needs reset
Wiring incorrect.
Press and hold reset button
for at least three (3)
seconds.
Check for crimping and
pins positioning (see
FIGURE 1).
Incorrect set point on
IPS.
Set IPS alarm point.
Defective IPS.
Check and replace IPS, if
defective.
Defective circuit.
Return to MATHESON for
repair.
Cylinder is below set
point, but the green light
stays on, and there is no
audible alarm.
Defective IPS.
Check and replace IPS, if
defective.
Defective circuit.
Return to MATHESON for
repair.

9
Lights change from green
to red when cylinder is
empty but will not reset
when cylinder is replaced.
Needs reset.
Partial cylinder -
replacement cylinder
pressure is not high
enough to surpass the
dead band of the IPS.
Press and hold reset button
for at least three (3)
seconds.
Replace with higher
pressure cylinder (full
cylinder).

10
IX. DRAWINGS

11

166 Keystone Drive
Montgomeryville, PA 18936
800-828-4313
www.mathesongas.com
MINT-0240 rev C
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nor can it accept responsibility for errors or omissions. This document is intended to serve as a general orientation and cannot be relied
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