The Seiko H022A is an advanced analog-digital quartz movement, introduced in the early 2000s and designed for professional-grade diver’s watches. This caliber is best known for its use in models like the Seiko Scuba Diver’s “Scubamaster” and other 200M+ diving watches. Packed with practical features, including depth measurement, dive time memory, and digital chronograph functions, the H022A represents one of Seiko’s most technically capable quartz movements for underwater use.

Core Specifications

• Caliber Number: H022A

• Movement Type: Quartz (Analog + Digital Hybrid)

• Battery Type: CR2025 lithium (3V)

• Battery Life: Approx. 2 years

• Display Type:

  • Analog: Hour, Minute, Seconds

  • Digital LCD: Depth data, chronograph, calendar, temperature, dive memory, alarms

• Water Resistance (case dependent): Usually 200m (20 bar), ISO-certified for scuba diving

• Backlight: EL (Electroluminescent)

• Temperature Range: Typically -10°C to +60°C

• Sensor: Pressure (depth) sensor built-in

• Size:

  • Diameter: ~31 mm

  • Thickness: ~7.0 mm

Main Digital Features

The H022A movement provides a full suite of diving functions:

• Depth Gauge – Measures depth in meters (0 to 80m range)

• Dive Time Log – Records max depth and dive duration

• Water Temperature Display – Real-time temperature during dive

• Surface Interval Timer – Tracks time between dives

• Chronograph – Measures up to 100 hours

• Daily Alarm – With audio notification

• Calendar – Automatic, including leap years

• Dual Time – Track two time zones

• Backlight – EL light for low visibility conditions

Its rugged design and purpose-built tools made it popular among recreational and professional divers alike.

Button Operation

The standard H022A watch has four push buttons:

• A (Top Left) – Mode selection

• B (Bottom Left) – Adjust/select

• C (Top Right) – Start/stop/increase

• D (Bottom Right) – Reset/light

Mode Options:

1. Time Mode – Digital and analog display

2. Dive Mode – Activates depth sensor automatically when submerged

3. Chronograph Mode – Stopwatch function

4. Alarm Mode – Set and toggle alarm

5. Memory Mode – View stored dive data

6. Dual Time Mode – Set second time zone

Analog and Digital Synchronization

Analog time is adjusted separately via crown or in digital sync mode:

1. Press Mode to access time adjustment

2. Hold Set until digits flash

3. Use +/- to change time

4. Press Set again to confirm

In some models, analog hands can be advanced digitally to match the LCD time after battery change or reset.

Battery Replacement and Reset

Steps for battery service:

1. Open the screw-down or snap-back case carefully.

2. Remove the CR2025 battery using plastic tweezers.

3. Insert the new battery properly, observing polarity.

4. Locate the AC contact near the battery slot.

5. Short the AC point to the battery’s negative terminal using metal tweezers to reset the circuit.

6. Reassemble the case, ensuring seals are intact to maintain water resistance.

After a reset, all user settings (alarm, dive logs, etc.) will be erased.

Troubleshooting Common Issues

Due to its complexity, full movement replacement may be required in some cases.

Final Thoughts

The Seiko H022A is one of Seiko’s most advanced quartz movements engineered for diving. It combines analog elegance with digital precision and practical tools that make it perfect for underwater adventures. From dive memory to depth sensing, the H022A offers unparalleled value for serious divers and collectors of functional tool watches. Its durability, feature set, and Seiko heritage ensure it remains a standout among hybrid quartz calibers.