Introduction
The Dwyer Magnehelic Series 605 Indicating Transmitter is designed for both visual monitoring and electronic control of very low differential pressure. This device is suitable for control applications in building HVAC systems, providing local indication for routine maintenance and system troubleshooting. It combines the reliable Dwyer Magnehelic gauge mechanical design with Series 600 transmitter technology, offering a two-wire, 4-20 mA control signal. The terminal strip on the rear simplifies connection to any 4-20 mA control loop powered by a 10-35 VDC supply.
Figure 1: Front view of a Dwyer Magnehelic Indicating Transmitter. The dial displays pressure in inches of water, with a visible range from 0 to 1.0. The face includes the "Magnehelic" brand, "Indicating Transmitter" label, maximum pressure rating (25 PSIG), and patent information. Adjustment screws for "SPAN" and "ZERO" are visible at the bottom, along with the Dwyer logo. Note that the specific model 605-3 covered in this manual has a 0-3.0"WC range.
Safety Information
Read this manual thoroughly before installing, operating, or servicing this device. Failure to follow these instructions may result in product damage, property damage, or serious injury. Keep this manual for future reference.
- Ensure all electrical connections comply with local and national electrical codes.
- Disconnect power before making any wiring connections to prevent electrical shock.
- Do not exceed the maximum pressure rating of 25 PSIG.
- Installation and service should only be performed by qualified personnel.
Specifications
| Parameter | Value |
|---|---|
| Model Number | 605-3 |
| Pressure Range | 0-3.0"WC (Inches of Water Column) |
| Output Signal | 4-20 mA, 2-wire |
| Power Supply | 10-35 VDC |
| Maximum Pressure | 25 PSIG |
| Product Dimensions | 7.6 x 6.8 x 3.7 inches |
| Weight | 2.35 Pounds |
| Manufacturer | Dwyer Instruments |
Setup and Installation
Mounting
The Series 605 can be flush mounted or surface mounted. Ensure the mounting location is free from excessive vibration and within the specified operating temperature range. The device should be mounted vertically for accurate readings.
- Select a suitable location for mounting.
- Secure the transmitter using appropriate hardware (not included).
- Ensure the pressure ports are accessible for tubing connections.
Pressure Connections
Connect the pressure tubing to the high and low pressure ports located on the back of the unit. Use appropriate tubing and fittings for the application. The high pressure port is typically marked "HIGH" or "+", and the low pressure port "LOW" or "-".
- Connect the higher pressure source to the "HIGH" port.
- Connect the lower pressure source to the "LOW" port.
- Ensure all connections are leak-free.
Electrical Wiring
The Series 605 utilizes a two-wire, 4-20 mA output. Connect the transmitter to a 10-35 VDC power supply and the control system as follows:
- Connect the positive (+) terminal of the power supply to the positive (+) terminal of the transmitter.
- Connect the negative (-) terminal of the transmitter to the input of the control system (e.g., PLC, DCS).
- Complete the loop by connecting the return of the control system to the negative (-) terminal of the power supply.
- Ensure proper polarity to avoid damage.
Operation
Power On
Once all connections are secure, apply power to the unit. The analog output will begin to transmit a 4-20 mA signal corresponding to the measured differential pressure.
Reading the Display
The Magnehelic gauge provides a local visual indication of the differential pressure. The red pointer on the dial indicates the current pressure in inches of water column ("WC").
Zero and Span Adjustment
The Series 605 features external zero and span adjustments. These adjustments affect both the visual indication and the 4-20 mA output.
- Zero Adjustment: With no pressure applied (both ports open to atmosphere or connected to the same pressure), adjust the "ZERO" screw (typically located at the bottom right of the dial) until the pointer reads 0"WC. This also calibrates the 4 mA output.
- Span Adjustment: Apply a known full-scale pressure (e.g., 3.0"WC for a 0-3.0"WC range). Adjust the "SPAN" screw (typically located at the bottom left of the dial) until the pointer reads the full-scale value. This calibrates the 20 mA output. Repeat zero and span adjustments as necessary for optimal accuracy.
Maintenance
The Dwyer Magnehelic Series 605 is designed for minimal maintenance. Regular checks ensure continued accuracy and reliable operation.
- Periodic Calibration: It is recommended to periodically verify the zero and span calibration, especially if accuracy is critical or after significant environmental changes.
- Cleaning: Keep the exterior of the unit clean. Use a soft, damp cloth. Do not use abrasive cleaners or solvents.
- Pressure Port Inspection: Periodically inspect pressure tubing and connections for leaks or blockages.
- Environmental Conditions: Ensure the operating environment remains within the specified temperature and humidity ranges.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No Indication / No Output | No power; Incorrect wiring; Blocked pressure ports; Damaged unit. | Check power supply (10-35 VDC); Verify wiring connections and polarity; Inspect pressure ports and tubing for obstructions; Contact technical support if unit is damaged. |
| Inaccurate Readings | Out of calibration; Leaks in pressure lines; Incorrect mounting position; Environmental factors. | Perform zero and span calibration; Check all pressure connections for leaks; Ensure unit is mounted vertically; Verify operating environment. |
| Output Signal Stuck at 4 mA or 20 mA | Sensor fault; Wiring issue; Over-range/Under-range pressure. | Check pressure applied is within range; Verify wiring integrity; Contact technical support. |
Warranty and Support
Dwyer Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of one year from the date of shipment. For full warranty details, technical support, or service, please contact Dwyer Instruments directly. Contact information can be found on the official Dwyer website.
Dwyer Instruments, Inc.
Michigan City, IN 46360 U.S.A.
www.dwyer-inst.com
