Series A3000 Photohelic® Pressure Switch/Gage

3-in-1 Indicating Gage, Lo-limit and Hi-limit Control

Photohelic® Switch/Gages function as versatile, highly repeatable pressure switches combined with a precise pressure gage employing the time-proven Magnehelic® gage design. The Photohelic® switch/gage measures and controls positive, negative or differential pressures of air and compatible gases. Standard models are rated to 25 psig (1.7 bar) with options to 35 (2.4) or 80 (5.5 bar) psig. Single pressure 36000S models measure to 6000 psig (413 bar) with a 9000 psig (620 bar) rating. Two phototransistor actuated, DPDT relays are included for low/high limit control. Easy to adjust set point indicators are controlled by knobs located on the gage face. Individual set point deadband is one pointer width - less than 1% of full scale. Set points can be interlocked to provide variable deadband - ideal for control of fans, dampers, etc. Gage reading is continuous and unaffected by switch operation, even during loss of electrical power. Choose from full scale pressure ranges from a low 0-.25" (0-6 mm) w.c. up to 30 psi (21 bar); single positive pressure to 6000 psig (413 bar).

Photohelic Sensing - How It Works
In typical applications, these Dwyer switch/gages control between high and low pressure set points. When pressure changes, reaching either set point pressure, the infrared light to the limiting phototransistor is cut off by the helix-driven light shutter. The resulting phototransistor signal is electronically amplified to actuate its DPDT slave relay and switching occurs. Dead band between make and break is 1% of full scale or less - just enough to assure positive, chatter-free operation.

Relay-Transformer Features
A plastic housing protects all electronic components. Solid-state and integrated circuit electronics are on glass-epoxy printed circuit boards and self-extinguishing terminal boards.

Please see SERIES AT3A3000 for ATEX approved.

Product Applications

  • Air Conditioner Systems
  • Clean Rooms
  • Fume Exhaust Systems

Models & Ordering

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Build Your Custom Part. Use our Product Configurator

Model Number Description Usually Ships Price Order
A3000-0 Pressure switch/gage, range 0-.50" w.c. Same Day $286.00 Order
A3000-00 Pressure switch/gage, range 0-.25" w.c. Same Day $301.00 Order
A3001 Pressure switch/gage, range 0-1.0" w.c. Same Day $286.00 Order
A3002 Pressure switch/gage, range 0-2.0" w.c. Same Day $286.00 Order
A3003 Pressure switch/gage, range 0-3.0" w.c. Same Day $286.00 Order
A3004 Pressure switch/gage, range 0-4.0" w.c. Same Day $286.00 Order
A3005 Pressure switch/gage, range 0-5.0" w.c. Same Day $286.00 Order
A3006 Pressure switch/gage, range 0-6.0" w.c. Same Day $286.00 Order
A3008 Pressure switch/gage, range 0-8.0" w.c. Same Day $286.00 Order
A3010 Pressure switch/gage, range 0-10" w.c. Same Day $286.00 Order
A3015 Pressure switch/gage, range 0-15" w.c. Same Day $286.00 Order
A3020 Pressure switch/gage, range 0-20" w.c. Same Day $286.00 Order
A3025 Pressure switch/gage, range 0-25" w.c. Same Day $286.00 Order
A3030 Pressure switch/gage, range 0-30" w.c. Same Day $286.00 Order
A3040 Pressure switch/gage, range 0-40" w.c. Same Day $286.00 Order
A3050 Pressure switch/gage, range 0-50" w.c. Same Day $286.00 Order
A3060 Pressure switch/gage, range 0-60" w.c. Same Day $286.00 Order
A3080 Pressure switch/gage, range 0-80" w.c. Less than 1 Week $286.00 Order
A3100 Pressure switch/gage, range 0-100" w.c. Same Day $286.00 Order
A3150 Pressure switch/gage, range 0-150" w.c. Same Day $286.00 Order

Can't find what you need? Try our Product Configurator

Specifications

GAGE SPECIFICATIONS
Service:
Air and non-combustible, compatible gases.
Wetted Materials:
Consult Factory.
Accuracy:
±2% of FS at 70°F (21.1°C). ±3% on -0 and ±4% on -00 models.
Pressure Limits:
-20" Hg. to 25 psig (-0.677 to 1.72 bar). MP option; 35 psig (2.41 bar), HP option; 80 psig (5.52 bar). A36003S – 36010S; 150 psig (10.34 bar). A36020S and higher; 1.2 x full-scale pressure.
Temperature Limits:
20 to 120°F. (-6.67 to 48.9°C). Low temperature option available.
Process Connections:
1/8" female NPT.
Size:
4" (101.6 mm) dial face, 5" (127 mm) O.D. x 8-1/4" (209.55 mm).
Weight:
4 lb (1.81 kg).

SWITCH SPECIFICATIONS
Switch Type:
Each setpoint has 2 Form C relays (DPDT).
Repeatability:
±1% of FS.
Electrical Rating:
10A @ 28 VDC, 10A @ 120, 240 VAC.
Electrical Connections:
Screw terminals. Use 167°F (75°C) copper conductors only.
Power Requirements:
120 VAC, 50/60 Hz; 240 VAC & 24 VAC power optional.
Mounting Orientation:
Diaphragm in vertical position. Consult factory for other position orientations.
Set Point Adjustment:
Adjustable knobs on face.
Agency Approvals:
CE, CSA, UL. Optional-EXPL explosion-proof enclosure does not possess any agency approvals.

Features

  • Bezel and front cover (with set point knobs and zero adjustment screw) removed to expose Photohelic® switch/gage set point mechanism.Cover is clear polycarbonate plastic.
  • Gage pointer and light shutter are mounted on helix and balancing counterweight. Shutter passes through slot in optical limit switch to expose phototransistors to integral infrared light source or mask them depending on applied pressure.
  • Light shield effectively protects phototransistors from strong outside light sources yet allows free pointer movement. It also gives interior a clean "finished" look.
  • Optical limit switches are used for reliability and long service life. Attached directly to set pointers, they are individually aligned to assure precise switching accuracy.
  • Semi-Flexible drive shaft connects to set point knobs.
  • Zero adjustment screw connects to screw in cover to adjust zero pressure reading.
  • Plastic enclosure protects electronic components and electrical connections.
  • Polycarbonate connection or terminal board is self-extinguishing.
  • Glass epoxy printed circuit boards for durability and permanence.
  • Load relays are DPDT with latching feature for maximum application versatility.
  • Electronics are designed to operate on 50/60 Hz, 120 volt current with 10% over or under voltage. Special units for other voltages are available.
  • Switch set pointers show switch settings at all times.
  • Spring loaded friction clutch prevents operator damage of set point mechanism.

Options

  • High & Low Latching Circuits. Dwyer Photohelic® switch/gages can be wired for high-latching, low-latching or combination high-low latching circuits. That is, the equipment will hold in these respective positions once activated and until manually reset. This can be particularly useful for alarm and signal applications where control is accomplished by another Photohelic® switch/gage or other means. Complete wiring and operational instructions are included. Where manual reset is required a dry circuit push button such as Dwyer Part A-601 should be used.
  • -SR Single contact, right set point, for actuation on increasing or decreasing pressure.
  • -OLS OEM Model, less relay and transformer components and housing but including infared diodes and phototransistor(s), light shutter and set pointer(s). For single or double contact.
  • -RMR Remote-Mounted Relay, relay pack may be mounted remotely from gage. Standard length is 5 ft. For other lengths, specify cable length required.
  • -TAMP Tamper-proof knobs, low temperature option, special scales, voltages and other features and modifications are available.
  • Special Housings available include Weatherproof (NEMA 4) and Explosion-proof (NEMA 7 & 9; NEC Cl I, Gr C&D; Cl II, Gr E, F&G; Cl III). Contact Customer Service for detailed dimension drawings.
  • Scale No. 3401 Square Root Specify Range.
  • Scale No. 3402 Blank Scale Specify Range.

Accessories

Model Number Description Usually Ships Price Order
A-298 Flat aluminum bracket for flush mounting Photohelic® & Capsuhelic® gages, 603A, 605, and 3000MR. Same Day $26.75 Order
A-320-B Enclosure for 3000MR Photohelic® Switch/Gage, Series 605 Magnehelic® Differential Pressure Transmitter, DH3 Digihelic® Pressure Controller, Series 2000 Magnehelic® Gage with medium and high pressure options, 4-13/16" (122.24 mm). Same Day $222.00 Order
A-601 Manual reset switch. Same Day $37.50 Order

Videos

Model Chart

 
EXAMPLE A3000-00N 24VAC Series A3000-00N-24VAC Photohelic® Pressure Switch/Gage, range .05-0-0.2" w.c., with 24VAC relay pack.
RANGE A3000-00N
A3000-00
A3000-0
A3001
A3002
A3003
A3004
A3005
A3006
A3008
A3010
A3015
A3020
A3025
A3030
A3040
A3050
A3060
A3080
A3100
A3150
A3300-0
A3301
A3302
A3304
A3310
A3320
A3330
A3000-00AV
A3000-0AV
A3001AV
A3002AV
A3010AV
A3201
A3202
A3203
A3204
A3205
A3210
A3215
A3220
A3230
A3000-5HG
A3000-10HG
A3000-15HG
A3000-20HG
A3000-25HG
A3000-30HG
A3000-40HG
A3000-50HG
A3000-60HG
A3000-6MM
A3000-10MM
A3000-20MM
A3000-25MM
A3000-50MM
A3000-80MM
A3000-100MM
A3000-150MM
A3000-200MM
A3000-250MM
A3000-300MM
A3000-500MM
A3000-5000MM
A3300-20MM
A3300-30MM
A3000-200MMHG
A3000-1CM
A3000-2CM
A3000-5CM
A3000-8CM
A3000-10CM
A3000-15CM
A3000-20CM
A3000-25CM
A3000-30CM
A3000-40CM
A3000-50CM
A3000-80CM
A3000-100CM
A3000-150CM
A3000-200CM
A3000-250CM
A3000-300CM
A3300-4CM
A3300-10CM
A3300-20CM
A3300-30CM
A3000-60PA
A3000-125PA
A3000-250PA
A3000-500PA
A3000-750PA
A3300-250PA
A3300-500PA
A3000-.5KPA
A3000-1KPA
A3000-1.5KPA
A3000-2KPA
A3000-3KPA
A3000-4KPA
A3000-5KPA
A3000-8KPA
A3000-10KPA
A3000-15KPA
A3000-20KPA
A3000-25KPA
A3000-30KPA
A3300-1KPA
A3300-2KPA
A3300-3KPA
A3000-5MBAR
A3000-25MBAR
  .05-0-.2" w.c.
0-0.25" w.c.
0-0.5" w.c.
0-1" w.c.
0-2" w.c.
0-3" w.c.
0-4" w.c.
0-5" w.c.
0-6" w.c.
0-8" w.c.
0-10" w.c.
0-15" w.c.
0-20" w.c.
0-25" w.c.
0-30" w.c.
0-40" w.c.
0-50" w.c.
0-60" w.c.
0-80" w.c.
0-100" w.c.
0-150" w.c.
.25-0.25" w.c.
.5-0-.5" w.c.
1-0-1" w.c.
2-0-2" w.c.
5-0-5" w.c.
10-0-10" w.c.
15-0-15" w.c.
0-.25" w.c. & 300-2000 FPM AV
0-.5" w.c. & 500-2800 FPM AV
0-1" w.c. & 500-4000 FPM AV
0-2" w.c. & 1000-5600 FPM AV
0-10" w.c. & 2000-12500 FPM AV
0-1 psid
0-2 psid
0-3 psid
0-4 psid
0-5 psid
0-10 psid
0-15 psid
0-20 psid
0-30 psid
0-5" Hg
0-10" Hg
0-15" Hg
0-20" Hg
0-25" Hg
0-30" Hg
0-40" Hg
0-50" Hg
0-60" Hg
0-6 mm w.c.
0-10 mm w.c.
0-20 mm w.c.
0-25 mm w.c.
0-50 mm w.c.
0-80 mm w.c.
0-100 mm w.c.
0-150 mm w.c.
0-200 mm w.c.
0-250 mm w.c.
0-300 mm w.c.
0-500 mm w.c.
0-5000 mm w.c.
10-0-10 mm w.c.
15-0-15 mm w.c.
0-200 mm Hg
0-1 cm w.c.
0-2 cm w.c.
0-5 cm w.c.
0-8 cm w.c.
0-10 cm w.c.
0-15 cm w.c.
0-20 cm w.c.
0-25 cm w.c.
0-30 cm w.c.
0-40 cm w.c.
0-50 cm w.c.
0-80 cm w.c.
0-100 cm w.c.
0-150 cm w.c.
0-200 cm w.c.
0-250 cm w.c.
0-300 cm w.c.
2-0-2" cm w.c.
5-0-5 cm w.c.
10-0-10 cm w.c.
15-0-15 cm w.c.
0-60 Pa
0-125 Pa
0-250 Pa
0-500 Pa
0-750 Pa
125-0-125 Pa
250-0-250 Pa
0-0.5 kPa
0-1 kPa
0-1.5 kPa
0-2 kPa
0-3 kPa
0-4 kPa
0-5 kPa
0-8 kPa
0-10 kPa
0-15 kPa
0-20 kPa
0-25 kPa
0-30 kPa
0.5-0-0.5 kPa
1-0-1 kPa
1.5-0-1.5 kPa
0-5 mbar
0-25 mbar
OPTIONS   24VAC
240VAC
AT
COO
DEED
EDED
EDDE
ED
EXPL
G
HC
HL
HP
LH
LL
OLS
LT
M
MP
NIST
R
RMR
RMR1
RMR2
RMR3
RMR10
RMR15
RMR20
RMR25
RMR30
RMR40
RMR50
RMR60
RMR70
RMR80
RMR90
RMR100
SRH
SRL
ST
TA
TAMP
WP
Y
24 VAC Relay Pack
220/240 VAC Relay Pack
Aluminum Tag
Certificate of Origin
Energizing (set point low: de-energizing/energizing; set point high: energizing/de-energizing)
Energizing (set point low: energizing/de-energizing; set point high: energizing/de-energizing)
Energizing (set point low: energizing/de-energizing; set point high: de-energizing/energizing)
Energizing (set point: energizing/de-energizing)
Explosion-proof Housing with Breather & Drain
Green Scale Overlay
Horizontal Calibration (90° face up)
Latching Option (high/low)
High Pressure
Latching Option (low/high)
Latching Option (low/low)
Less Relay
Low Temperature
Mirror Scale Overlay
Medium Pressure
NIST Certificate of Calibration
Red Scale Overlay
Remote Mounted Relay Std. 5 Ft.
Remote Mounted Relay 1 Ft.
Remote Mounted Relay 2 Ft.
Remote Mounted Relay 3 Ft.
Remote Mounted Relay 10 Ft.
Remote Mounted Relay 15 Ft.
Remote Mounted Relay 20 Ft.
Remote Mounted Relay 25 Ft.
Remote Mounted Relay 30 Ft.
Remote Mounted Relay 40 Ft.
Remote Mounted Relay 50 Ft.
Remote Mounted Relay 60 Ft.
Remote Mounted Relay 70 Ft.
Remote Mounted Relay 80 Ft.
Remote Mounted Relay 90 Ft.
Remote Mounted Relay 100 Ft.
Single Right Hi Latching
Single Right Lo Latching
Stainless Steel Tag
Tilt Angle from Vertical in Degrees (-90 to 90)
Tamperproof Knobs
Weatherproof Housing
Yellow Scale Overlay

Product Literature

Manuals

Catalog Pages

Approvals

Drawings

Questions

Question
What restrictions, if any, are imposed for the Magnehelic® and Photohelic® gages in vacuum service?
Answer
In applications involving higher vacuums than 20" Hg, leakage due to gage housing porosity becomes the limiting factor.
Question
Are air velocity scales available?
Answer
Yes, the information we require to supply the proper range is the velocity (fpm or m/s) or velocity pressure (inches of water or kpa) and density of air (lb/ft3 or g/cm3).
Question
What is the NEMA rating of a Photohelic®?
Answer
Our standard is considered to be NEMA 1 rated for general purpose. We do have weatherproof (NEMA 4X) and explosion-proof (NEMA 7 & 9) enclosures available.
Question
What is an RMR Photohelic®?
Answer
The RMR option is for a remote mounted relay, where the relay pack is seperate from the gage. The unit comes with a standard interconnecting cable that is 3 feet long.

Apps

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