DWYER Series DH3 Digihelic® Differential Pressure Controller

RM 0.00



Series DH3 Digihelic® Differential Pressure Controller

3 in 1 Instrument: Gage, Switch and Transmitter, Square Root Output for Flow


The Series DH3 Digihelic® Differential Pressure Controller is a 3-in-1 instrument possessing a digital display gage, control relay switches, and a transmitter with current output all packed in the popular Photohelic® gage style housing. Combining these 3 features allows the reduction of several instruments with one product, saving inventory, installation time and money. The Digihelic® controller is the ideal instrument for pressure, velocity and flow applications, achieving a 1.5% full scale accuracy on ranges down to the extremely low 0.25″ w.c. to 2.5″ w.c. full scale. Ranges of 5″ w.c. and greater maintain 0.5% F.S. accuracy. Bi-directional ranges are also available.

The Series DH3 Digihelic® controller allows the selection of pressure, velocity or volumetric flow operation in several commonly used engineering units. 2 SPDT control relays with adjustable deadbands are provided along with a scalable 4-20 mA process output.

Programming is easy using the menu key to access 5 simplified menus which provide access to: security level; selection of pressure, velocity or flow operation; selection of engineering units; K-factor for use with flow sensors; rectangular or circular duct for inputting area in flow applications; set point control or set point and alarm operation; alarm operation as a high, low or high/low alarm; automatic or manual alarm reset; alarm delay; view peak and valley process reading; digital damping for smoothing erratic process applications; scaling the 4-20 mA process output to fit your applications range and field calibration.

NIST CALIBRATION available in Product Configurator.


Product Applications

  • SCFM flow in ducts
  • Filter status
  • Static pressures in ducts or buildings
  • Damper control
  • Fan control



  • Service: Air and non-combustible, compatible gases.
  • Wetted Materials: Consult factory.
  • Housing Material: Die cast aluminum case and bezel.
  • Accuracy: ±1.5% for 0.25″ and ±0.25″ w.c. ranges. Ranges 0.5″ to 5″ w.c. and corresponding bi-directional (except ±2.5″ w.c.) ±1%; All other ranges: ±0.5% @ 77°F (25°C) including hysteresis and repeatability (after 1 hour warm-up).
  • Stability: < ±1% per year.
  • Pressure Limits: Ranges (uni- and corresponding bidirectional), ≤ 1 in w.c.: 9 psi; 2.5 and 5 in w.c.: 1.5 psi; 10 in w.c.: 3 psi; 25 in w.c.: 8 psi; 50 in w.c.: 15 psi; 100 in w.c.: 20 psi.
  • Temperature Limits: 32 to 140°F (0 to 60°C).
  • Compensated Temperature Limits: 32 to 140°F (0 to 60°C).
  • Thermal Effects: 0.020%/°F (0.036/°C) from 77°F (25°C). For 0.25″ and ±0.25″ w.c. ranges: ±0.03%/°F (±0.054%/°C).
  • Power Requirements: 12 to 28 VDC, 12 to 28 VAC 50 to 400 Hz.
  • Power Consumption: 3 VA max.
  • Output Signal: 4 to 20 mA DC into 900 Ω max.
  • Zero & Span Adjustments: Accessible via menus.
  • Response Time: 250 ms (damping set to 1).
  • Display: Backlit 4 digit LCD 0.4″ height LED indicators for set point and alarm status.
  • Electrical Connections: 15 pin male high density D-sub connection. 18″ (46 cm) cable with 10 conductors included.
  • Process Connections: 1/8″ female NPT. Side or back connections.
  • Mounting Orientation: Mount unit in vertical plane.
  • Size: 5″ (127 mm) OD x 3-1/8″ (79.38 mm).
  • Weight: 1.75 lb (794 g).
  • Agency Approvals: CE.


  • Switch Type: 2 SPDT relays.
  • Electrical Rating: 1 A @ 30 VAC/VDC.
  • Set Point Adjustment: Adjustable via keypad on face.



  • 3-in-1 instrument allows the reduction of several instruments with one product, saving inventory, installation time and money
  • Full scale accuracy of 1.5% even on extremely low ranges, and 0.5% for ranges above 5 in w.c. provide for greater measurement precision
  • Secure menu program provides access to device operation only for the right skill level


Models & Ordering


Standard Ranges

Model Description
DH3-002 Differential Pressure Controller, range 0-0.25″ w.c.
DH3-003 Differential Pressure Controller, range 0-0.5″ w.c.
DH3-004 Differential Pressure Controller, range 0-1″ w.c.
DH3-005 Differential Pressure Controller, range 0-2.5″ w.c.
DH3-006 Differential Pressure Controller, range 0-5″ w.c.
DH3-007 Differential Pressure Controller, range 0-10″ w.c.
DH3-009 Differential Pressure Controller, range 0-25″ w.c.
DH3-010 Differential Pressure Controller, range 0-50″ w.c.
DH3-011 Differential Pressure Controller, range 0-100″ w.c.


Bi-Directional Ranges

Model Description
DH3-013 Differential Pressure Controller, range 0.25-0-0.25″ w.c.
DH3-014 Differential Pressure Controller, range 0.5-0-0.5″ w.c.
DH3-015 Differential Pressure Controller, range 1-0-1″ w.c.
DH3-016 Differential Pressure Controller, range 2.5-0-2.5″ w.c.
DH3-017 Differential Pressure Controller, range 5-0-5″ w.c.
DH3-018 Differential Pressure Controller, range 10-0-10″ w.c.



Additional information


DH3-002, DH3-003, DH3-004, DH3-005, DH3-006, DH3-007, DH3-009, DH3-010, DH3-011, DH3-013, DH3-014, DH3-015, DH3-016, DH3-017, DH3-018