DeWalt 12A-O1T9A39 Lawn Mower Manual

The DeWalt 12A-O1T9A39 is a 20-inch cordless electric walk-behind lawn mower powered by a 12Ah battery system. It features a brushless motor for extended runtime, a 3-in-1 mulching/bagging/side-discharge capability, a single-lever height adjustment (1.5" to 4"), a push-button start, a folding handle for storage, and a durable steel deck. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Steel cutting deck, Brushless motor, 12Ah Battery & Charger, Folding handle, Height adjustment lever, Grass bag, Safety key.

Assembly & Setup

Unpack and inspect all parts. Assemble on a flat, stable surface.

1. Attach the handle: Align lower handle brackets with deck mounts, secure with provided bolts and wrenches.
2. Install the grass bag: Attach bag support frame to rear discharge chute, hang bag onto frame hooks.
3. Install battery: Insert fully charged DCB612 battery into compartment on deck, ensure it clicks into place.
4. Attach side discharge chute (if not mulching/bagging): Snap onto side port.
5. Adjust cutting height: Move single lever to desired position (test on a flat surface).

WARNING! Ensure mower is turned OFF and battery is removed during assembly. Tighten all hardware securely.

First-Time Operation

Before first mow, fully charge the battery and perform a safety check.

1. Insert Safety Key: Push key into slot near handle until it clicks.
2. Check battery level: Press battery indicator button; ensure at least 2 bars for operation.
3. Select cutting mode: Install mulch plug, grass bag, or side chute as desired.
4. Start mower: Hold safety handle lever (deadman switch) and press START button.
5. Begin mowing: Walk at a steady pace, overlapping passes slightly for even cut.
6. After mowing: Release safety handle to stop blade. Remove Safety Key.

CAUTION! Always wear safety glasses and sturdy footwear. Clear lawn of debris before mowing.

Specifications

• Model: DeWalt 12A-O1T9A39
• Cutting Width: 20 inches
• Deck Material: Powder-coated steel
• Power Source: DeWalt 12Ah 60V MAX FLEXVOLT Battery (DCB612)
• Charger: DCB115 Rapid Charger (included)
• Cutting Height Range: 1.5 - 4 inches (7 positions)
• Weight (without battery): 65 lbs
• Wheels: 8" rear, 7" front
• Sound Rating: < 85 dB(A) at operator position
• Warranty: 3-year limited warranty

Controls and Settings

Main controls located on the upper handle. Front Panel: Battery compartment, Safety Key slot.

Handle Controls: Safety Handle Lever (deadman switch), START/STOP button, Battery Indicator button, Height Adjustment Lever.

Cutting Mode: Configure via mulch plug, bag, or side chute attachment. Height Adjustment: Single lever adjusts all four wheels simultaneously. Battery Management: LED indicator shows charge level (4 bars = full). Safety: Mower will not start unless Safety Key is inserted and safety handle is engaged.

Mowing Functions

3-in-1 cutting system for versatile lawn care.

1. Mulching: Install mulch plug in rear discharge. Cuts clippings finely and returns them to lawn as fertilizer.
2. Bagging: Attach grass bag to rear. Collects clippings for disposal. Empty bag when full (indicator window).
3. Side Discharge: Attach side chute for discharging clippings to the side. Use for tall or wet grass.
4. Height Adjustment: Stop mower. Move lever to desired setting. Ensure all wheels are at same height.
5. Folding Handle: For storage, loosen knobs at handle base, fold handle down toward deck.

Tip: For best results, mow when grass is dry. Never remove more than 1/3 of grass height in a single mow.

Battery & Charging

Uses DeWalt 60V MAX FLEXVOLT 12Ah battery (DCB612).

1. Charging: Insert battery into DCB115 charger. LED will flash red during charge, solid green when complete.
2. Runtime: Approximately 60 minutes per charge on typical lawn (varies with grass conditions).
3. Storage: Store battery in a cool, dry place. For long-term storage, charge to 50%.
4. Battery Indicator: Press button on battery or handle to see remaining charge (4 LEDs).
5. Replacement: Use only genuine DeWalt 60V MAX batteries. Do not use damaged batteries.

WARNING! Use only DeWalt chargers. Do not expose battery to fire or water. Keep away from children.

Safety Features

Safety Key: Must be inserted to operate. Deadman Switch: Blade stops within 3 seconds of releasing handle. Blade Brake System: Automatically stops blade when handle is released. Safety Labels: Read and understand all labels on mower.

Care & Maintenance

Unplug battery before any maintenance. Clean after each use.

1. Deck Cleaning: Tip mower on its side (air filter side up). Use brush or hose to remove grass buildup.
2. Blade Care: Periodically inspect blade for damage or dullness. Sharpen or replace as needed (use blade removal tool).
3. Wheel & Bearing Check: Ensure wheels turn freely. Lubricate axle points if necessary.
4. Storage: Store in a dry place. Fold handle. Remove battery for indoor storage.

CAUTION! Always disconnect battery. Wear gloves when handling blade. Do not use water on electrical components.

Regulatory Information

This product complies with applicable ANSI/OPEI standards and U.S. EPA regulations. Copyright © 2023 DeWalt. DeWalt, FLEXVOLT, and the yellow and black color scheme are trademarks of Stanley Black & Decker, Inc. For support, visit www.dewalt.com or contact 1-800-4-DeWalt (1-800-433-9258).

Troubleshooting

Reset: Remove Safety Key and battery for 1 minute to reset electronics.

Service: 1-800-4-DeWalt; www.dewalt.com