AT-95026B
Revised 08-05
A20 and A25 Series
Catalog Section 10
Temperature SWICHGAGE®
2 and 2-1/2 in. (51 and 64 mm) Dial
**
■
■
■
Corrosion Resistant Polycarbonate Case
Indicating Gage and Limit Switch
Switch Can Activate Alarms and/or Shut
Down Equipment
■
■
Critical/High Temperature Limit Switch
Is Visible and Adjustable (Most Models)
A20T Series
shown
Contact(s) Isolated From Ground
Case: Glass filled/Polycarbonate, corrosion-resis-
tant; steel mounting clamp included. Bezel:
Polished stainless steel, standard; others
are available.
®
A20TL and A25TL SWICHGAGE
For use on Ford Worldwide engines. Supplied with
special sensing bulb.
Description
The A20 Series (2 inch/51 mm dial) and the A25
®
Series (2-1/2 inch/64 mm dial) SWICHGAGE mod-
els are diaphragm-actuated, temperature-indicating
gages, with built-in electrical switches for tripping
alarms and/or shutdown devices.
®
A20TE and A25TE SWICHGAGE
Pointer: Tempered nickel silver; red tip.
Lens: Polycarbonate, high-impact.
A20TE (was A20ESR) and A25TE (was A25ESR).
Models with internal SPDT snap-switches, instead
of the single pole/pointer contact(s). When the
switch closes on rising temperature, it becomes Set.
As temperature decreases the switch Resets.
Model A25TE is CSA listed for
Ranges are available from 32-120°F (0-45°C) thru
Sensing Element: Beryllium copper diaphragm.
300-440°F (160-220°C).
Capillary: PVC armored copper; 4 ft. (1.2 m)*.
All models of these rugged, built-to-last instruments
are fully sealed from the environment by the unique
combination of a polycarbonate case and lens, a pol-
ished stainless steel bezel, and O-ring seals.
Stainless steel armor optional.
Sensing Bulb: Copper*.
non-hazardous areas. Model
Gage Accuracy: See accuracy chart, on page 2.
A25TE-EX is CSA listed for
Maximum Temperature: See Temperature Ranges
Class I, Division 1, Groups
These vapor/pressure actuated gages feature a sealed
capillary tube and a sensing bulb. When subjected to
heat, the liquid in the sensing bulb changes to vapor
creating pressure against a diaphragm mechanism.
The diaphragm translates this vapor pressure into a
mechanical gage reading.
and Factory Settings table on page 2.
C & D hazardous areas.
Adjustable Limit Contact (A20T and A25T):
SPST contact; pilot-duty only, 2 A @ 30 VAC/
VDC; isolated from case ground. Normally Closed
when the high limit is met. Normally Open when
pointer is in normal operating range. Contacts are
gold flashed silver.
®
A20TABS and A25TABS SWICHGAGE
Same as 20 and 25T with internal SPDT snap-
switch for pre-alarm.
For series A20T and A25T, the gage pointer acts as a
temperature indicator and as one switch pole which
completes a circuit when it touches the adjustable limit
contact. Contact(s) are isolated from ground. They have
self-cleaning motion to enhance electrical continuity.
Cylinder Head Temperature
®
A20TH and A25TH SWICHGAGE
Limit Contact Adjustment: by a 1/16 in. hex
wrench thru 100% of the scale.
A20TH (was A20TL8133) and A25TH (was
A25TL8133). For use on Air Cooled engines.
Wiring: A20T: Number 4 screw terminals;
A25T: Number 6 screw terminals.
Models A20TE and A25TE have internal snap-acting
Gage–Only Models
Snap-Switch Rating (A20TE and A25TE):
SPDT, 3 A@ 30 VDC inductive; 4 A @
125 VAC inductive.
®
SPDT switches.
A20TG and A25TG MURPHYGAGE
Gage-only models, without contacts
Gage without contact(s).
®
(MURPHYGAGE ) are also available.
Wiring: A20TE: Number 4 screw terminals;
A25TE: Number 6 screw terminals.
*
For optional capillary lengths, engine adapters, sensing bulbs
and range combinations, see Murphy bulletin T-8428B.
Applications
Unit Weight: A20 Series: 11.9 oz. (0.370 kg).
Applications for A20 and A25 Series temperature
**dPirroedcuticvtes 8c9o/v3e3r6ed/EbEyCthriesgbaurdllientginecleocmtrpolmyawgintehtiEcMC Council
compatibility except as noted.
A25 Series Models: 13.3 oz. (0.413 kg).
®
SWICHGAGE instruments include: engines and
Unit Dimensions: A20 Series: 4-3/4 x 4-3/4 x 3 in.
(121 x 121 x 76 mm). A25 Series Models: 4-3/4 x
4-3/4 x 2-3/4 in. (121 x 121 x 70 mm).
equipment in Oil Field, Marine, Irrigation Construction
,
and Trucking industries. Monitoring Engine Coolant
temperature, Crankcase Oil, Transmission Oil.
Base Models
Specifications
Coolant or Oil Temperature
Dial: White on black; U.S.A. standard scale is dual
scale °F/°C; others available.
®
A20T and A25T Series SWICHGAGE
For these models the gage pointer makes with an
adjustable contact to complete a pilot-duty circuit.
Bulletin AT-95026B page 1 of 4
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Magnetic Switch
®
INDUCTIVE AND HIGH CURRENT LOADS REQUIRE THE USE OF A
TATTLETALE Magnetic Switches show the cause of shutdown for applica-
tions that include: capacitor discharge or magneto ignitions, battery systems and
electric motor driven equipment. Typical wiring diagrams are shown below.
®
MAGNETIC SWITCH. The SWICHGAGE contacts are for light-duty elec-
trical switching to operate alarms or control devices. Murphy manufactures the
®
Magnetic Switch for protection of the pilot-duty SWICHGAGE limit contacts.
®
A20T Temperature
SWICHGAGE®
A20P Pressure
518PH TATTLETALE
117 Magnetic Switch
SWICHGAGE®
A20T Temperature
SWICHGAGE®
R
LOW
N. C.
HIGH
G
NC
SW1
SW2
B
HIGH
C
S
B
®
N.O. SWICHGAGE
instruments
C
C
N. O.
C
N. O.
_
Energized To Run Devices
+
Battery
Energized To Run Devices
_
+
Battery
N.C. switches option
Pre-Alarm Using A20/A25TABS
The A20TABS and A25TABS features a standard limit contact for equipment
shutdown on high temperature. It also has an internal SPDT snap-switch to sig-
nal an alarm before shutting down. When the snap-switch trips (preset point), on
and the shutdown circuit will be completed (see the typical diagram below for
reference). The front contact shutdown limit setting (which is adjustable) and
the snap-switch are preset at the factory. Refer to “Temperature Ranges and
rising temperature, the switch completes a circuit to activate an alarm. If the Factory Settings” table on opposite page for settings. For alternative alarm
temperature continues to increase, the face-adjustable pointer contact will make before shutdown, see Magnetic Switch model 760A or 761APH.
Alarm Before
Shutdown
518PH
A20TABS
TATTLETALE®
SWICHGAGE®
MINI-SIREN®
R
G
NC
SW1
SW2
B
ABS
N. C.
HIGH
N. O.
C
Shutdown Device
or Ignition Circuit
Opens circuit to
_
shutdown engine.
+
Battery
Typical Internal Wiring Diagrams
Pointer shown in the shelf position. Pointer type contact rating: pilot-duty 2 A @ 30 VAC/VDC resistive.
Snap-acting switch rating: 3 A @ 30 VDC inductive. 4 A @ 125 VAC inductive.
A20T
A20T-HL
A20TABS
A20TE
HIGH
N. O.
LOW
HIGH
RESET
ABS
HIGH
SET
N. O.
N. O.
N. O.
N. C.
C
N. C.
C
N. C.
C
N. C.
C
A25T
A25TABS
A25TABS-HL
A25TE
A25T-HL
N. O.
N. O.
N. O.
N. O.
N. O.
C
C
C
N. C.
C
N. C.
C
N. C.
N. C.
N. C.
RESET
SET
RESET
SET
RESET
SET
HIGH
LOW
HIGH
HIGH
LOW
HIGH
H
L
P
H
H
H
H
P
P
P
L
L
L
L
P
Bulletin AT-95026B page 3 of 4
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How to Order
To order, use the diagram below. List options in ascending alphabetical order (A-Z). Example: A20T-B1-250-4.
____ – ____ – ____ – ____ – ____
Base Model
Adapter Nuts†††
A20TG
A25T
A20T
1/8 = 1/8-27 NPT
1/4 = 1/4-18 NPT
3/8 = 3/8-18 NPT
3/8B = 3/8-19 BSPT
3/8K = 3/8 NPSF
Metric
A20TL
A20TO
A20TE
A20TABS
A20TB
A20TH
M10 = 10 mm x 1.5
M12 = 12 mm x 1.5
M14 = 14 mm x 1.5
M16 = 16 mm x 1.5
M18 = 18 mm x 1.5
M20 = 20 mm x 1.5
M22 = 22 mm x 1.5
M24 = 24 mm x 1.5
A25TL
A25TE
A25TABS
A25TH
A25TG
–
= 1/2-14 NPT††††
1/2B = 1/2-BSPT
1/2K = 1/2 NPSF
5/8 = 5/8-18 UNF
3/4 = 3/4-14 NPT
3/4U = 3/4-16 UNF
7/8 = 7/8-9 UNC
†††
Options†
Specific adapter nut must
match the sensing bulb.
Standard.
††††
B1 = Black bezel
EX = Explosion-proof (CSA Listed for
Class I, Div. 1, Groups C & D)*
EL = Explosion-proof less case
HL = High and low contacts
K = Knob adjusting face contact
Temperature Capillary Armor Type
and Length
Capillary Armor Type
Blank = PVC armor, copper capillary
S = Stainless steel armor, copper capillary
OS = Oil sealed (Silicone Oil)
UA = Temperature bulb style “A” (10-05-0166)
UB = Temperature bulb style “B” (10-01-0061)
UC = Temperature bulb style “C” (10-01-0060)
UD = Temperature bulb style “D” (10-00-0286)
UE = Temperature bulb style “E” (10-01-0084)
UF = Temperature bulb style “F” (10-00-0577)
UG = Temperature bulb style “G” (10-00-0578)
UH = Temperature bulb style “H” (10-00-2466)
UJ = Temperature bulb style J (10051153)
UK = Temperature bulb style K (10054886)
Capillary Length (specify after capillary type;
example: “S4”)
4 = 4 ft. (1.2 m)
Specify other length = Available in 2 ft. increments
thru 20 ft.; 5 ft. increments above 20 ft. (0.5 m.
increments from 1.5–10 m.; 2 m. increments thru
34 m. Specify “M” following length, i.e. 1.5M.)
Range††
Dual scale (°F/°C)
Single scale (°C)
°F
°C
†
*
70C = 0-70°C
Options not available on all models or configurations.
A25TE-EX only is CSA listed for hazardous locations.
120 = 32-120
160 = 32-160
0-49
0-71
100C = 45-100°C
120C = 50-120°C
140C = 60-140°C
160C = 70-160°C
**
This option is not covered by the CE mark.
220 = 130-220 54-104
250 = 130-250 60-121
300 = 140-300 60-149
320 = 160-320 71-160
350 = 180-350 82-177
440 = 300-440 149-227
Illumination – Order Separately
A20 Series: Clamp Lite Assembly; 12 V= 05702176; 24 V= 05702177
A25 Series: N/A.
††
Consult factory for availability of dials other than °F/°C. Select scale
so your normal operating temperature is in the upper half of the scale.
Warranty
A limited warranty on materials and workmanship is given with
this FW Murphy product. A copy of the warranty may be viewed
CONTROL SYSTEMS & SERVICES DIVISION
FRANK W. MURPHY, LTD.
Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.
+44 1722 410055 fax +44 1722 410088
e-mail [email protected]
P.O. Box 1819; Rosenberg, Texas 77471; USA
+1 281 633 4500 fax +1 281 633 4588
e-mail [email protected]
FW Murphy
INDUSTRIAL PANEL DIVISION
P.O. Box 470248
Tulsa, Oklahoma 74147 USA
+1 918 317 4100 fax +1 918 317 4266
e-mail [email protected]
P.O. Box 470248
MURPHY DE MEXICO, S.A. DE C.V.
Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje
San Luis Potosí, S.L.P.; México 78384
+52 444 8206264 fax +52 444 8206336
Villahermosa Office +52 993 3162117
e-mail [email protected]
Tulsa, Oklahoma 74147 USA
+1 918 317 4100 fax +1 918 317 4266
e-mail [email protected]
www.fwmurphy.com
Printed in U.S.A.
In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.
Bulletin AT-95026B page 4 of 4
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