SEIKO 8L35 / 8L55 Dive Watch Manual

Introduction

Thank you for choosing SEIKO. Please read this manual carefully for correct and safe operation. Keep it for future reference.

Note 1: Bracelet adjustment services are typically offered by the retailer where the watch was purchased. If you received the watch as a gift or have relocated, contact SEIKO Customer Service. Some retailers may offer this service for a fee.

Note 2: If your watch has a protective film to prevent scratches, remove it before use. Failure to do so can lead to dirt, sweat, or moisture buildup, potentially causing rust.

General Warnings

⚠️ IMPORTANT: Read and strictly follow these instructions before operating the watch.

Safety Precautions for Diving

Before Diving

PRECAUTION: Before diving (excluding scuba diving), check the following:

• The watch is functioning normally.
• The power reserve is sufficient (for mechanical watches).
• The rotating bezel turns smoothly (not too loose or too tight).
• The crown and any buttons are securely tightened.
• There are no defects on the bracelet or crystal (e.g., gaps, cracks).
• The bracelet is securely fastened.

If any issues are found, do not use the watch for diving.

PRECAUTION: Do not operate the crown or buttons while underwater.

PRECAUTION: Due to the demanding conditions of diving, periodic servicing (every 2-3 years) is recommended to ensure the watch's internal mechanism remains in optimal condition.

During Diving

WARNING: During dives, do not perform any operations other than those specified in this manual. Incorrect handling or misinterpretation of information can lead to death or serious injury.

WARNING: This dive watch is a supplementary instrument primarily for time indication, not a safety device. Use it in conjunction with other necessary equipment (e.g., depth gauge, residual pressure gauge) for safe diving.

WARNING: Never use this watch for saturation diving with helium.

WARNING: Do not dive with this watch unless you have received proper training, acquired sufficient experience, and are thoroughly familiar with safe diving procedures. Check all functions before each dive.

PRECAUTION: Do not operate the crown or buttons when the watch is wet. Water can enter the watch. If condensation appears on the inside of the crystal, water resistance may be compromised. Consult a retailer or SEIKO Customer Service immediately.

PRECAUTION: Do not leave moisture, sweat, or dirt on the watch for extended periods. This can lead to rust, especially on metal parts. Water resistance may decrease over time due to aging seals and gaskets.

PRECAUTION: Remove the watch before bathing or using a sauna. Steam, soap, and chemicals in hot springs can degrade water resistance.

After Diving

Rinse the watch with fresh water to remove any salt residue and dry it thoroughly with a soft cloth to prevent rust. Do not pour tap water directly onto the watch; use a bowl of water.

PRECAUTION: Depending on the diving environment, watch components may be affected. Regular servicing (every 2-3 years) is recommended.

How to Use

1. Using the Rotating Bezel

The rotating bezel can be used to measure elapsed time from a specific event.

1. At the start of an event (e.g., beginning of a dive), align the bezel's reference mark (▼) with the minute hand. The bezel rotates only counter-clockwise. Do not force it clockwise.
2. The elapsed time is indicated by where the minute hand points on the bezel's graduation. For example, if a dive starts at 10:10 and 20 minutes have passed, the minute hand will point to the '20' mark on the bezel.

Note: The bezel is designed for one-way rotation (counter-clockwise) to prevent accidentally showing less elapsed time than has actually passed, which is critical for air supply management during dives.

PRECAUTION: Always check your air supply before diving. Use the elapsed time indication on the bezel solely as a reference.

2. Screw-Lock Crown

This watch features a screw-lock crown for enhanced water resistance and to prevent accidental operation.

• To Use: Unscrew the crown by turning it counter-clockwise. Then, pull it out to the desired position (1st or 2nd click).
• After Use: Always screw the crown back down clockwise while gently pushing it towards the case until it stops. Ensure it is fully locked.

3. Winding the Mainspring (Mechanical Watch)

This is an automatic watch with manual winding capability.

• The mainspring winds automatically through normal wrist movements. It can also be wound manually using the crown.
• To start a watch that has stopped, wind it manually or shake it gently until the second hand moves. Then, set the time and date.
• To wind manually, unscrew the crown, then turn it clockwise. Turning the crown counter-clockwise will not wind the watch. Turning it clockwise until it stops fully winds the mainspring. Overwinding will not damage the spring.
• A fully wound watch will run for approximately 50 hours (8L35) or 55 hours (8L55).
• To maintain accuracy, wear the watch for at least 10 hours a day. If not worn, wind it fully every day at the same time.
• If the watch stops due to the mainspring being fully unwound, it may not start immediately upon winding. Gently shaking the watch can help initiate movement.

4. Setting Time and Date

The date changes approximately every 24 hours, around midnight. Incorrect AM/PM setting can cause the date to change at noon.

PRECAUTION: Do not set the date between 8:00 PM and 2:00 AM. Doing so may cause the date to fail to change correctly.

1. Unlock the crown by turning it counter-clockwise.
2. Pull the crown out to the 1st click.
3. Set the Date: Turn the crown clockwise until the date of the *previous* day is displayed. Then, turn the crown clockwise to advance to the current date. (Example: To set the date to '6', first set it to '5', then turn clockwise to '6').
4. Pull the crown out to the 2nd click to set the time. When the second hand is at the 12 o'clock position, it will stop. Turn the hands forward until the date changes to the next day (indicating AM). Then, set the correct time.
5. Push the crown back to its normal position when the second hand starts moving. (Using a time signal is recommended for precise second hand setting).
6. Lock the crown by screwing it clockwise.

PRECAUTION: For mechanical watches, set the minute hand slightly *before* the desired time and then advance it to the exact time.

Adjusting Date at Month End

Correct the date at the end of February and for months with 30 days.

Example: Setting the date on the 1st of a month following a 30-day month. If the watch shows '31', pull the crown to the 1st click, turn clockwise to set the date to '1', then push the crown back to its normal position.

PRECAUTION: Lock the crown. Do not set the date between 8:00 PM and 2:00 AM.

5. Bracelet Adjustment for Diving

This watch may feature a bracelet with a dive extension function for easy length adjustment, useful when wearing over a wetsuit or thick clothing.

1. Lift the clasp to approximately 90°, then press it down further about 20° and hold. This requires light force.
2. Gently pull the bracelet from the 6 o'clock side to extend the slider. The slider can extend approximately 30mm. Do not force it beyond this limit.
3. Press the button and lift the clasp to open the buckle. Put the watch on.
4. Close the clasp (4-1) first, then the safety clasp (4-2).
5. Adjust the slider length to ensure a comfortable fit on your wrist.

6. Using the Dive Extension

If your watch has a dive extension, its length can be easily adjusted.

1. Lift the clasp.
2. Press the button to open the clasp. (Press the clasp again to return it to its normal position).
3. Open the two-part folding section of the extension by pulling it in the direction of the arrow. This may require some force and will click open.
4. Slide the upper cover of the extension in the direction of the arrow, then pull upwards to fully extend the two-part section.
5. Put the watch on, close the clasp (5-1) first, then the safety clasp (5-2).

To fold the extension, reverse the procedure. It will click shut when fully retracted.

Care and Maintenance

Daily Care

• Do not operate the crown when it is pulled out.
• Wipe off moisture, sweat, and dirt with a soft, dry cloth.
• After exposure to saltwater, rinse the watch with fresh water and dry thoroughly. Do not pour tap water directly onto the watch; use a bowl of water.
• Do not wash watches classified as "not waterproof" or "water resistant for daily use."

Periodically Rotate the Crown

• Periodically rotate the crown to prevent corrosion, especially if it is a screw-lock type.

Performance and Specifications

The caliber and specifications are indicated on the case back of the watch.

• Caliber: 8L35 / 8L55
• Vibrations per hour: 28,800 / 36,000
• Accuracy: ±15 to -10 seconds per day (average daily rate), when worn on the wrist at temperatures between 5°C and 35°C.
• Type of Drive: Automatic winding with manual winding mechanism.
• Power Reserve: Approximately 50 hours (8L35) / 55 hours (8L55).
• Jewels: 26 / 37.

Note: Factory accuracy is adjusted under specific conditions. Actual daily accuracy may vary based on factors like wearing habits, temperature, and activity levels.

Lumibrite

SEIKO's Lumibrite is a luminous paint that absorbs light energy and emits it in darkness. It can provide illumination for 3-5 hours after being exposed to light (e.g., >500 lux for 10 minutes). The brightness may fade over time. Lumibrite is safe and non-toxic.

Magnetic Field Resistance

Strong magnetic fields can temporarily affect watch accuracy (causing it to gain, lose, or stop). This watch meets or exceeds JIS Class 1 standards for magnetic resistance.

WARNING:

• Keep the watch at least 5 cm (approx. 2 inches) away from devices with magnetic fields (JIS Level 1).
• Keep the watch at least 1 cm (approx. 0.4 inches) away from devices with magnetic fields (JIS Level 2).

If the watch becomes magnetized and its accuracy is significantly affected, it will require demagnetization and repair, which may be a chargeable service.

Common sources of magnetic fields include: Smartphones, tablets, computers, speakers, magnetic clasps, and certain household appliances.

Bracelet Care

Metal bracelets can accumulate sweat and dirt, leading to corrosion or skin irritation. Clean regularly with a soft cloth. For stubborn dirt, rinse the bracelet in water (protecting the watch case) and gently clean with a soft toothbrush. Some titanium bracelets use stainless steel pins which may rust; address this promptly to prevent damage.

Strap Care

• Polyurethane/Silicone Straps: Can fade or degrade. Clean with water and a damp cloth. Avoid solvents. If flexibility decreases, replace the strap to prevent breakage.

Skin Irritation

If you experience skin irritation, discontinue wear and consult a medical professional. This can be due to allergies, friction, or dirt.

Servicing

For optimal performance and longevity, it is recommended to have your watch serviced approximately every 2-3 years. This includes disassembly, cleaning, lubrication, and adjustment. Water resistance seals should also be replaced during servicing.

PRECAUTION: Regular servicing is essential. Contact an authorized SEIKO retailer or SEIKO Customer Service.

Troubleshooting

Watch Stops Working:

• Cause: Mainspring unwound. Solution: Wind the watch (see Winding Mainspring section). If it still doesn't work, consult a retailer.

Watch Temporarily Gains/Loses Time:

• Cause: Exposure to extreme temperatures or strong magnetic fields. Solution: Normal accuracy should return when the watch is returned to normal conditions and away from magnetic sources.
• Cause: Dropped, impacted, or subjected to strong vibrations. Solution: If accuracy does not recover, consult a retailer.
• Cause: Not serviced for over 3 years. Solution: Consult a retailer.

Date Changes at 12 PM:

• Cause: Incorrect AM/PM setting. Solution: Manually advance the time by 12 hours.

Condensation Under Crystal:

• Cause: Minor water ingress due to worn gasket. Solution: Consult a retailer.

For any issues not listed, please consult an authorized SEIKO retailer.

Technical Specifications

Note: Actual accuracy may vary based on usage conditions.