Dwyer® 477B Handheld Digital Manometer User Manual

Product Overview

The Dwyer® 477B Handheld Digital Manometer is a versatile, battery-operated instrument designed for measuring positive, negative, or differential pressures. It offers high accuracy and supports multiple pressure units, making it suitable for various applications. Key features include a memory function for storing readings, a backlight for low-light conditions, a hold feature, and audible/visual overpressure alarms.

Figure 1: Front view of the Dwyer 477B Handheld Digital Manometer, displaying the digital readout and control buttons for ON/OFF, ZERO/STORE, HOLD/MEMORY, and UNITS/LOC.

Key Features

• Accuracy: ±0.10% FS from 60 to 78°F (15.6 to 25.6°C); ±1% FS from 32 to 60 and 78 to 104°F (0 to 15.6 and 25.6 to 40°C).
• Temperature Limits: Operating: 0 to 140°F (-17.8 to 60°C); Storage: -4 to 176°F (-20 to 80°C).
• Power Requirements: Operates on a 9-volt alkaline battery.
• Connections: Two barbed connections designed for 1/8" (3.18 mm) or 3/16" (4.76 mm) I.D. tubing.
• Measures positive, negative, or differential pressures.
• Selectable pressure units (English and metric).
• Memory function for storing up to 40 readings.
• Backlight for improved visibility in low-light conditions.
• Hold feature to freeze current readings.
• Visual and audible overpressure alarms.

Setup

Battery Installation

The manometer requires a 9-volt alkaline battery for operation. The battery is included but may not be connected upon arrival. To install or replace the battery:

1. Locate the battery compartment cover on the back of the unit.
2. Unscrew the two retaining screws at the base of the instrument to remove the battery cover.
3. Connect the 9-volt battery to the battery clip.
4. Place the battery into the compartment and replace the cover, securing it with the screws.

Figure 2: Bottom view of the manometer, highlighting the battery compartment cover and its retaining screws.

Connecting Tubing

The manometer features two barbed connections for tubing. Connect 1/8" (3.18 mm) or 3/16" (4.76 mm) I.D. tubing to these ports depending on your application. Ensure connections are secure to prevent leaks and ensure accurate readings.

Operating Instructions

The back of the Dwyer 477B provides a quick reference for operating instructions. Refer to the image below for a visual guide to the controls and their functions.

Figure 3: Back view of the Dwyer 477B Handheld Digital Manometer, showing the printed operating instructions and specifications.

Power On/Off

• Press ON/OFF to toggle the device on and off.
• The device will automatically shut off after 20 minutes of inactivity to conserve battery life.
• To illuminate the display backlight, hold ON/OFF down during power-on. Release when lit.

Zeroing the Manometer

• Vent both pressure ports to the atmosphere.
• Press and hold ZERO/STORE until the LCD displays "----", then release it.

Unit Selection

• Press UNITS/LOC to cycle through and select desired pressure units.

Hold and Memory Function

• Hold Reading: Press HOLD/MEMORY to hold the current reading. Press again to resume measurement.
• Memory Function:
  • To store a reading: Press and hold HOLD/MEMORY until "ST01" (or next available memory location) is displayed, then release. If needed, press UNITS/LOC to select another storage location before releasing.
  • To view stored data: Press and hold HOLD/MEMORY until "LOC" is displayed. If needed, press UNITS/LOC to view other memory locations.
  • To exit memory mode: Press HOLD/MEMORY again.
  • To clear all data: Press and hold HOLD/MEMORY until "CLR" is displayed, then press ZERO/STORE.

Damping Function

• Press and hold HOLD/MEMORY until "DAMP" is displayed, then release the HOLD/MEMORY button.
• Press ZERO/STORE or UNITS/LOC to adjust the damping level (default is 3).
• To exit damping mode, press HOLD/MEMORY again.

Maintenance

Battery Replacement

When the "LOW BAT" indicator appears on the display, it is time to replace the 9-volt alkaline battery. Refer to the "Battery Installation" section under Setup for detailed steps. Recommended battery types include DURACELL MN 1604, EVEREADY 522, or equivalent.

Cleaning

Clean the exterior of the manometer with a soft, damp cloth. Do not use abrasive cleaners or solvents, as these may damage the casing or display. Ensure no liquid enters the pressure ports or other openings.

Troubleshooting

Specifications

Warranty and Support

This Dwyer® product is manufactured by Dwyer Instruments, Inc. For specific warranty information, technical support, or service inquiries, please contact Dwyer Instruments, Inc. directly. Details regarding warranty periods and terms are typically provided with the product packaging or can be found on the manufacturer's official website.

Manufacturer: Dwyer Instruments, Inc.