Model
DH-015
Range
-2.5 to 0 to 2.5 in w.c.
Accuracy
±0.5% FS
Output
4-20 mA
Relays
2 SPDT, 8 A
Comms
Modbus RS485
Dwyer DH-015 Digihelic Differential Pressure Controller
The Dwyer DH-015 is a 3-in-1 Series DH Digihelic® controller that combines a digital display gage, two control relays, and a scalable 4-20 mA transmitter in a single 1/8 DIN panel instrument. The DH-015 is factory ranged for -2.5 to 0 to 2.5 in w.c. and holds ±0.5% full-scale accuracy at 77°F (25°C), including hysteresis and repeatability. The DH-015 reads bidirectional differential pressure across its -2.5 to 0 to 2.5 in w.c. range in field-selectable engineering units. Velocity and volumetric flow modes are not available on this range.
Best For
- Filter and air-handler status monitoring
- Clean room, building, and isolation room pressurization
- Fume hood and exhaust pressure monitoring
- Damper and fan control with dual set points
Warranty
Key Features
3-in-1 Instrument
Replaces a separate gage, switch, and transmitter with one device, reducing inventory, panel space, and installation time.
Dual SPDT Control Relays
Two 8 A relays with independent, keypad-adjustable on/off set points let you run two-stage control or set point plus alarm logic.
Scalable 4-20 mA Transmitter
The current output is field-scaled with POL/POH so 4 mA and 20 mA map to any reading inside the unit’s range.
Modbus RTU over RS485
9600 baud Modbus RTU lets the controller read and write to a BAS or PLC; up to 128 units can share one daisy-chained bus.
Bidirectional Sensing
Reads pressure in both directions across the -2.5 to 0 to 2.5 in w.c. range, ideal for tracking pressure that swings positive and negative about a reference.
Universal Power Input
Accepts 100-240 VAC or 24 VDC, so the same unit drops into line-powered or 24 VDC control-panel applications.
Technical Specifications
| Model | DH-015 |
| Operating Range | -2.5 to 0 to 2.5 in w.c. |
| Operating Modes | Pressure only (velocity and flow not available on this range) |
| Service | Air and non-combustible, compatible gases |
| Accuracy | ±0.5% FS at 77°F (25°C), incl. hysteresis and repeatability |
| Stability | < ±1% per year |
| Pressure (Overpressure) Limit | 2 psi for this model |
| Temperature Limits | 32 to 140°F (0 to 60°C) |
| Thermal Effect | 0.020%/°F (0.036%/°C) from 77°F (25°C) |
| Output Signal | 4-20 mA DC into 900 Ω max, scalable |
| Display | 4-digit LCD, 0.4 in height; LED set point & alarm indicators |
| Control Relays | 2 SPDT, 8 A at 240 VAC resistive |
| Serial Communications | Modbus® RTU, RS485, 9600 baud, 8-N-1, address 1-247 |
| Power | 100-240 VAC (50-400 Hz) or 132-240 VDC; or 24 VDC ±20% |
| Power Consumption | 7 VA max (high voltage); 130 mA max at 24 VDC |
| Response Time | 250 ms (dampening = 1) |
| Process Connections | Compression fitting for 1/8 in ID x 1/4 in OD tubing; optional barbed fitting for 3/16 in ID (-B) |
| Housing | ABS plastic, UL 94 V-0 |
| Enclosure Rating | Face designed to meet NEMA 4X (IP66) |
| Mounting | 1/8 DIN panel, horizontal orientation; cutout 1.772 x 3.620 in (45 x 92 mm) |
| Weight | 14.4 oz (408 g) |
| Agency Approvals | UL Listed, cUL Listed (File E83725), CE |
Documentation
Frequently Asked Questions
What pressure range does the Dwyer DH-015 cover?
The DH-015 is factory ranged for -2.5 to 0 to 2.5 in w.c.. The 4-digit display and 4-20 mA output are both scaled to this range.
Can the DH-015 control equipment on its own?
Yes. The DH-015 has two built-in SPDT relays rated 8 A at 240 VAC, each with an independent keypad-set turn-on and turn-off point, so it can switch fans, dampers, or alarms without an external controller.
Does the DH-015 support BAS integration?
Yes. The DH-015 provides Modbus® RTU over RS485 at 9600 baud and a scalable 4-20 mA analog output, so it integrates with most building automation and PLC systems.
Can the DH-015 measure air velocity or volumetric flow?
No. Velocity and flow modes are not available on the DH-015 range; it operates as a bidirectional differential pressure instrument with display, relays, and 4-20 mA output.
Is the DH-015 a bidirectional unit?
Yes. The DH-015 reads pressure in both directions across -2.5 to 0 to 2.5 in w.c., which suits applications where the measured pressure swings positive and negative about a reference.
What power input does the DH-015 require?
The DH-015 accepts either 100-240 VAC (50-400 Hz) / 132-240 VDC high-voltage power or 24 VDC low-voltage power, making it suitable for both line-powered and 24 VDC control-panel installations.
- Brand:
- Dwyer
- Series:
- Digihelic
- Product Type:
- Differential Pressure Controller
- Pressure Range:
- -2.5 to 0 to 2.5 in w.c.
- Bidirectional:
- Yes
- Output Signal:
- 4-20 mA
- Control Relays:
- Dual SPDT
- Communication:
- Modbus RTU RS485
- Display:
- Digital LCD
- Mounting:
- 1/8 DIN Panel
