APT-18 is designed for 1-3 person households, provide stable water pressure for showers, dishwashers, washing machines, and other fixtures.
APT-18 has a total volume of 18 liters (4.5 gallons). The tank is designed for a maximum operating pressure of 10 bar (150 psi) and a maximum operating temperature of 90 °C (194 °F). It is factory pre-charged to 2 bar (30 psi) for stable system performance.
With a diameter of 28.0 cm and a height of 36.5 cm, the lightweight 3.4 kg design makes installation quick and convenient while saving space.
Product Overview
The APT-18 is a 18-liter (4.5 gallon) diaphragm pressure tank designed for residential and light commercial booster pump and electric submersible pump (ESP) systems. It stabilizes water pressure and reduces pump cycling.
APT-18 is ideal for regions with unstable or fluctuating municipal water pressure, widely used in homes and buildings where booster pumps are required. Its hygienic internal design, separate water from compressed gas and prevent water contact direct with the tank shell, ensures safe operation for cold sanitary water circuits, pressurized systems, and water storage applications.
Manufactured with premium materials and certified by NSF, CE, WaterMark, IAPMO, and other international bodies, APT-18 complies with global standards including those in the United States, Europe, Australia, and Asia. Produced in ISO-certified facilities, Aquasky pressure tanks delivers long service life, dependable performance, and safe drinking-water compatibility.
Certification
Specifications and Technical Data
| Parameter | Value |
| Model Number | APT-18 |
| Total Tank Volume | 18 liters / 4.5 gallons |
| Diameter | 28.0 cm / 11.0 inch |
| Height | 36.5 cm / 14.4 inch |
| Net Weight (NW) | 3.4 kg / 7.5 lbs. |
| Gross Weight (GW) | 3.8 kg / 8.4 lbs. |
| Shipping Volume | 1.08 CUF |
| Operating Temperature | 1 - 90°C / 34 - 194°F |
| Factory Pre-charge | 2 bar | 30 psi |
| Max. Operating Pressure | 10 bar | 150 psi |
| Connection | 1” NPT / BSPT Stainless Steel |
| Liner Material | Polypropylene |
| Diaphragm Material | Butyl Rubber |
| Shell | Cold Rolled Carbon Steel |
| External Coating | Triple Grade Blue Paint |
| Pre-charge Gas | 100% Nitrogen |
Key Features & Design Advantages
How the Pumplus Pressure Tank Works
APT-18 stores supplemental water between the butyl rubber diaphragm and the polypropylene liner, while the nitrogen-filled air chamber maintains constant system pressure. When water demand occurs, the compressed nitrogen pushes water into the system at a controlled pressure.
This design ensures stable performance and supports reliable operation for showers, faucets, dishwashers, washing machines, and other fixtures.
Key benefits
Typical Applications
Frequently Asked Question (FAQ)
A: Yes. A 18-liter (4.5-gallon) tank is generally sufficient for most 2-story homes with 1-3 people. The APT-18 can support 2–3 faucets running at the same time, provides stable water pressure for showers, and can reduce booster pump start/stop frequency by over 50%.
In case your home has 3-5 people, 2-3-story, or frequent high-volume, simultaneous water usage -> Choose APT-24. It supports 3-4 faucets at once and offers greater reserve capacity.
Quick guide:
APT-18: 1-3 people, 2-story, 2-3 outlets.
A: We strongly recommend having the APT-18 installed by a qualified plumber or technician for the following reasons:
Safety & Proper Setup: The APT-18 is a pressure vessel, and correct installation is critical. A professional will ensure:
System Compatibility: The tank must be correctly integrated with your booster pump, pressure switch, and piping system to ensure stable performance and avoid operational issues.
Warranty Protection: Installation by a non-professional may affect your product warranty coverage. A professional technician can typically complete the installation, testing, and calibration within 2–3 hours.
A: The APT-18 is designed to be “maintenance-free”.
Simply check the pre-charge pressure once every 1–2 years using a standard tire pressure gauge. If the pressure is low, you can refill the Nitrogen by yourself or ask a plumber to do it.
Service Life: Under normal operating conditions (water temperature ≤ 99°C, pressure ≤ 10 bar), APT-18 designed to last over 10 years. Many of our customers have used it for over 15 years with normal operation.
Warranty: We offer a 3-year factory warranty covering manufacturing defects and material flaws.
Installation Tip: Ask your plumber to measure your water pressure during installation and recommend the most suitable system configuration.
Customized Colors & Packaging
We offer a wide range of customization options to match your exact needs - from custom colors to branded packaging and logo design.
Watch our video to explore the possibilities and see how we help your products stand out in the market.
Downloads & Certification Links
Collection of all relevant product certifications.