Pressurebox Pro Tennis — User Manual & Support Guide

Full user guide for the Pressurebox Pro Tennis (A4B) automatic ball pressurizer. This page mirrors the printed manual supplied in the box and is kept up to date.

Quick start

Only insert dry balls. Moisture inside the container can permanently damage the pressure sensor.

1. Open the lid and insert the balls. (Check that the product is deflated before opening the lid by pressing the deflate button, and ensure the balls are surface dry and still have some pressure – completely flat balls cannot be used.)
2. Close the lid firmly until the logo on the lid aligns with the transparent part of the cylinder.
3. Set the power switch to ON and leave it there. The compressor will build up internal pressure in about 55-75 seconds when balls are inside (high-pressure mode takes a little longer).
4. Keep the device switched on until your next game. The internal pressure is automatically regulated and maintained.
5. When you’re ready to play next time, set the power switch to OFF and use the deflate button on the lid to release the pressure. You will hear a hissing sound (“psshhh”). Afterward, unscrew the lid and remove your pressurized balls.

Important notes

• Do not attempt to open the lid before deflating the container.
• Do not point the lid towards your face or body when opening.
• Close the lid firmly for an airtight seal, but avoid overtightening, as pressurized containers may become harder to open over time.
• Use the Pressurebox between game sessions and store the device at room temperature to ensure the best performance over time.
• If the pump activates often or the battery drains quickly, make sure the lid is sealed tightly and check for leaks.
• It is advisable to use dry balls with high-quality felt that still have some internal pressure.

Controls and LED reference

Press the battery/mode button briefly to see the battery level. Press and hold it for 3+ seconds to switch between the two pressure programs.

What you see	What it means
Four lights	Battery fully charged
One flashing red LED	Battery is low – recharge soon
Green LEDs in sequence	Charging in progress. All four light up steadily for a few seconds when charging is complete, then turn off – so a device with no lights has finished charging
Solid green	Normal mode – maintains around 20–22 psi. Ideal for relatively fresh balls, to maintain and gradually restore bounce. This is the default mode at every power-on
Solid blue	High-pressure mode – maintains around 26–28 psi. Ideal when you want faster balls or quicker pressure restoration
Four red LEDs blinking	Large air leak – see troubleshooting below
Red LEDs running / chasing	Pressure rises too slowly – see troubleshooting below
Four red LEDs solid	Small leak detected, device paused – see troubleshooting below
No lights	Standby. The device watches the pressure silently and only wakes the LEDs when something happens

Battery

A fully charged battery typically lasts up to 60 days, depending on usage and airtightness. Ensure the lid is properly sealed according to the instructions for optimal battery life. Charge the battery using the supplied USB-C cable. After charging, switch the power OFF and back ON to resume automatic operation.

Troubleshooting

Before you troubleshoot: always charge the battery fully first. A single run is limited to 5 minutes – if the target pressure is not reached, the device stops and shows an error. After 3 full pressurize–deflate cycles in a row, let the device cool for at least 15 minutes.

Four red LEDs blinking – large air leak

• Check that the lid is fully tightened.
• Deflate, open, and check that the main O-ring is in place and undamaged; refit it or replace it with the spare. See Adjusting the O-ring for a step-by-step guide.
• Check that the deflate valve is not stuck.

Red LEDs running / chasing – pressure rises too slowly

• Recharge fully and restart the device.
• Switch off and let the device cool for 1 hour, then try again.
• For high-pressure mode: run normal mode first, let it stop, then switch to high-pressure (the “relay” method). If the error remains, the pump may be worn – contact support.

Four red LEDs solid – small leak detected

The device refilled 3 times within 2 hours and paused itself to protect the motor.

• Was the device in severe cold? See special conditions below.
• Remove fluff and debris from the threads and sealing surfaces.
• If it continues, replace the main O-ring – see Adjusting the O-ring.
• Reset: switch the power OFF, then ON again.

Cleaning and fixing air leaks

If the product leaks air, try tightening the lid first. If the problem persists, clean the sealing surfaces. Then open and close the lid firmly a few times, and finally seal.

If the problem continues, the O-ring may need adjusting or replacing. In short: deflate and open the device, remove the O-ring from the lid, wipe the ring and the sealing surfaces with a slightly damp cloth (water only), check the ring for damage or flat spots, refit it evenly in its groove – or fit one of the spare O-rings supplied in the box – then close and reopen the lid firmly a few times before sealing. Our step-by-step O-ring guide shows each step.

Never use solvent-based or aggressive cleaning agents. Do not expose the product to running water.

Special conditions

Cold weather (below 5 °C)

• Battery capacity drops sharply in the cold – a freshly charged device may show a low battery or a much shorter life. This is normal for lithium batteries.
• The seal stiffens in severe cold and can leak (frequent restarts or solid red lights), and the lid can become harder to open.
• After cold storage (for example a winter car), let the device rest at about 20 °C for 24 hours before charging or use.
• For use around −10 °C, the included bottle sealing ring can temporarily reinforce the seal. Remove it when temperatures return to normal – otherwise the lid becomes very hard to open.

High altitude (2,000 m and above)

• The difference between inside and outside pressure is larger. Hold the deflate button until the hissing has completely stopped before opening – never force the lid.
• The pump can sound louder or hollow at start-up in thin air. This is normal.
• Reaching the target pressure takes longer and can trigger the 5-minute safety stop. For high-pressure mode, run normal mode first, let it stop, cool for 10 minutes, then switch to high-pressure.

Long-term storage

• If you will not use the device for more than a month, charge it to 50–80 % (three lights) before storing, and top it up every 3 months. Never store the device with an empty battery.

Safety instructions

• Use the device only as intended.
• Do not attempt to open the lid before deflating the container, and do not point the lid towards your face or body when opening.
• Close the lid firmly for an airtight seal, but avoid overtightening, as pressurized containers can become harder to open over time.
• Store and use within the specified temperature range: do not store or use the device below 5 °C (41 °F) or above 40 °C (104 °F). Extreme heat can cause the pressure level to rise, while cold can cause the balls to lose internal pressure.
• Do not use a damaged or defective device.
• Keep the device out of the reach of children and away from water. Only insert dry balls – moisture inside the container can damage the pressure sensor.
• Do not place the device in direct sunlight or use it in an explosive, condensing, or dusty environment.
• Charge with the supplied USB-C cable and a 5V/1A or 5V/2A charger.
• Unplug the charging cable before switching the device on.
• Avoid rapid, repeated pressurize–deflate cycles – frequent restarts heat up the pump and shorten pump and battery life.
• Avoid strong impacts. If the device is dropped while pressurized, press the deflate button and check the body for cracks before further use.
• Dispose of used batteries according to local regulations. Never dispose of batteries with household waste.

Specifications

• Model number: A4B
• Ball capacity: 4 balls (compatible with tennis & padel balls)
• Battery: Rechargeable lithium-ion, 3.7 V, rated capacity 2600 mAh
• Battery life: up to 60 days (varies with pressure, temperature, and usage)
• Charging time: 4.5 hours, charging current 5V/1A
• Operating environment: 5–40 °C; 5–93 % RH, non-condensing; barometric 86–105 kPa
• Max working pressure: 28 psi (1.93 bar)
• Over-pressure protection: relief valve opens at 36 psi (2.48 bar)
• Thermal protection: automatic shutdown if the electronics reach 80 °C
• Recommended service life: 5 years from date of manufacture
• Warranty: 1-year limited (statutory rights unaffected)

What’s in the box

• Automatic Ball Pressurizer
• USB-C charging cable
• 2 spare O-rings

Warranty, certifications and disposal

We provide a one-year warranty from the date of purchase. Within this period, we will, at our sole discretion, repair or replace the unit free of charge for any defects in materials or manufacturing. The warranty does not cover damage caused by misuse, accidents, or unauthorized modifications.

Pressurebox is CE, RoHS, and FCC certified, ensuring compliance with safety, environmental, and electromagnetic compatibility standards. At the end of its service life, please dispose of the device responsibly. To recycle the device, contact your local recycling center or follow the instructions on our website.

More help

Still stuck? See the Pressurebox Pro FAQ or contact us – we answer every message.