HM Digital AP-2 AquaPro Water Quality Electrical Conductivity Tester User Manual

1. Introduction

The HM Digital AP-2 AquaPro Electrical Conductivity (EC) Tester is a precision instrument designed to measure the electrical conductivity and temperature of water. This device provides a convenient and accurate way to assess water quality for various applications, including water filtration systems, hydroponics, and general water testing.

Key features of the AP-2 Tester include:

• Measures electrical conductivity (EC) and temperature.
• Automatic Temperature Compensation (ATC) for accurate readings.
• Water-resistant housing for durability.
• Digital Calibration (push button) for easy adjustment.
• Auto-off function to conserve battery life.
• Data-hold function to freeze readings.
• Low-battery indicator.
• Measurement Range: 0-9999 µS.

2. Product Overview

The HM Digital AP-2 tester features a compact design with an LCD display and intuitive buttons for operation. Below is an image illustrating the device's main components.

Figure 1: HM Digital AP-2 AquaPro Electrical Conductivity Tester. The image shows the white tester with a grey control panel. The panel includes an LCD screen at the top, followed by buttons labeled "POWER", "MODE", and "HOLD". Arrow buttons (up and down) are also visible. The HM Digital logo is located near the bottom of the device.

Key Components:

• LCD Display: Shows EC readings in µS and temperature in Celsius.
• POWER Button: Turns the device on and off.
• MODE Button: Used for switching between measurement modes or for calibration.
• HOLD Button: Freezes the current reading on the display.
• Electrodes: Located at the bottom of the device, these are immersed in the water sample for measurement.
• Battery Compartment: Located at the top or back, houses the CR-2032 lithium battery.

3. Setup

3.1. Battery Installation

The AP-2 tester requires one CR-2032 Lithium Metal battery (included). To install or replace the battery:

1. Locate the battery compartment, typically at the top or back of the device.
2. Open the compartment cover.
3. Insert the CR-2032 battery, ensuring correct polarity (+/-).
4. Close the battery compartment cover securely.

3.2. Initial Power-On

After battery installation, press the POWER button to turn on the device. The display should illuminate, showing the current EC and temperature readings (if electrodes are in a solution) or default values.

4. Operation

4.1. Taking a Measurement

1. Remove the protective cap from the bottom of the tester.
2. Press the POWER button to turn on the device.
3. Immerse the electrode end of the tester into the water sample, ensuring the electrodes are fully submerged but not exceeding the maximum immersion level indicated on the device.
4. Gently stir the tester to remove any air bubbles and allow the reading to stabilize. This typically takes a few seconds.
5. Read the Electrical Conductivity (EC) value in micro-Siemens (µS) and the temperature in Celsius from the LCD display.
6. To hold the reading on the display, press the HOLD button. Press it again to release.
7. After use, rinse the electrodes with distilled water and replace the protective cap.

4.2. Automatic Temperature Compensation (ATC)

The AP-2 tester features Automatic Temperature Compensation (ATC), which automatically adjusts the EC reading to a standard reference temperature (typically 25°C). This ensures accurate and consistent readings regardless of the sample's temperature.

4.3. Auto-Off Function

To conserve battery life, the AP-2 tester will automatically turn off after a period of inactivity (typically 10 minutes). This feature helps extend the battery's operational time.

5. Calibration

The HM Digital AP-2 tester is factory calibrated to a 1413 µS solution. While it is designed to maintain accuracy, recalibration may be necessary over time or if readings appear inconsistent. The device features digital push-button calibration.

To perform a digital calibration:

1. Obtain a fresh, standard 1413 µS calibration solution.
2. Turn on the AP-2 tester.
3. Immerse the electrodes into the 1413 µS calibration solution.
4. Press and hold the MODE button for approximately 5 seconds until the display starts flashing.
5. The tester will automatically recognize the 1413 µS solution and calibrate itself. The display will stop flashing once calibration is complete.
6. Rinse the electrodes with distilled water and replace the protective cap.

Note: Always use fresh calibration solutions. Do not reuse calibration solutions as their conductivity can change over time due to evaporation or contamination.

6. Maintenance

6.1. Cleaning the Electrodes

Regular cleaning of the electrodes is crucial for accurate readings. Rinse the electrodes with distilled or deionized water after each use. If there is visible residue or buildup, gently clean the electrodes with a soft brush or cotton swab and a mild detergent solution, then rinse thoroughly with distilled water.

6.2. Storage

Store the AP-2 tester with its protective cap securely in place. Keep the device in a cool, dry environment away from direct sunlight and extreme temperatures. Avoid storing the device in calibration solution or tap water.

6.3. Battery Replacement

When the low-battery indicator appears on the display, replace the CR-2032 Lithium Metal battery as described in Section 3.1. Prompt battery replacement ensures consistent performance.

7. Troubleshooting

• No Display / Device Not Turning On:

  Check battery installation and ensure the battery has sufficient charge. Replace the CR-2032 battery if necessary.

• Inaccurate or Unstable Readings:

  Ensure electrodes are clean and free of debris. Rinse with distilled water. Recalibrate the device using a fresh standard calibration solution (refer to Section 5).

  Ensure the electrodes are fully submerged in the sample and gently stirred to remove air bubbles.

• "Err" or Error Message on Display:

  This may indicate a sensor issue or a problem during calibration. Try cleaning the electrodes and recalibrating. If the error persists, contact customer support.

8. Specifications

9. Warranty and Support

For warranty information and technical support, please refer to the documentation included with your purchase or contact HM Digital directly. Warranty terms may vary based on region and retailer.

It is recommended to retain your proof of purchase for warranty claims.