New Products
Technical Data
My Catalogue
Quality System
Turnaround Times
Request Quote
Career Opportunities
Satisfaction Survey
Alpha Controls & Instrumentation Inc.
You are not logged in. Click here to login.
(800) 567-8686
Calibration Services
Product Search
Trade Shows
Contact Us
Quote Cart
My Orders
Shopping Cart

Authorized Fluke Calibration Service Center
Join Our Mailing List
Receive our monthly electronic communications!
You can revoke permission at any time by using the Unsubscribe link found at the bottom of every email.

Dwyer Photohelic Pressure Gauge & Switch

Products»Dwyer»Photohelic® Pressure Gauges & Switches
Photohelic® Pressure Switch/Gauge (Series A3000)
Manufacturer: Dwyer

3-in-One 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® design. The Photohelic® 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 setpoint indicators are controlled by knobs located on the gage face. Individual setpoint deadband is one pointer width - less than 1% of full scale. Setpoints 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).


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.


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 (for the Series A3000 only).


In both series of pressure switch/gages, you get the convenience of a visual indication plus high-low limit switching. For both OEM and in-plant applications, the Photohelic® switch/gage is used to control pressures in air conditioning systems, clean rooms, fluidic and pneumatic control systems, materials handling equipment, alarm or control fume exhaust systems, control pressure in air structures, and monitor respiratory and blood pressures.


Two phototransistor-actuated circuits and two DPDT relays permit both high and low alarms or limit controls. Relays are de-energized when gage pointer is to the left of respective set points; relays are energized as pointer passes to the right of set points. Loss of electrical power or loss of pressure provide "fail safe" protection.

Photohelic® Pressure Switch/Gauge



Service: Air and non-combustible, compatible gases.

Wetted Materials: Consult Factory.

Accuracy: ±2% of full scale 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). 36003S – 36010S; 150 psig (10.34 bar). 36020S 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 Type: Each setpoint has 2 Form C relays (DPDT).

Repeatability: ±1% of full scale.

Electrical Rating: 10A @ 28 VDC, 10A @ 120, 240 VAC;

Electrical Connections: Screw terminals.

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: UL,CSA, CE.


 Your browsing history
 Photohelic® Pressure Switch/Gauge
Copyright © 2018 Alpha Controls & Instrumentation Inc..  All rights reserved.