DOYIN 4SP3-18 1.5HP 3-Phase Stainless Steel Submersible Pump — 1.25" Outlet

The DOYIN 4SP3-18 is a compact 1.5HP three-phase AC submersible pump built with a stainless steel impeller for corrosion resistance in demanding borehole conditions. With a 1.25-inch outlet and a flow rate of 4.2m³/h (4,200 litres per hour), it delivers reliable performance for a recommended depth of up to 96 metres, with a maximum head of 112M — the entry-level model in DOYIN's 3-phase stainless steel pump range.

This pump suits smaller domestic boreholes, household water points, and light farm use where moderate depth and dependable flow are needed. The stainless steel impeller offers added protection against mineral content and mild salinity in borehole water, making it a solid option for coastal properties in Mombasa, Malindi, Diani, Kilifi, and Lamu, as well as inland areas with access to three-phase power.

As a three-phase AC pump, the 4SP3-18 requires a three-phase power supply and a matching three-phase AC controller sized to its 1.5HP rating for correct, protected operation. It is not solar-compatible in this configuration and is best suited to properties with stable grid or generator-backed three-phase electricity.

CoastalSolar Africa supplies, sizes, and installs the 4SP3-18 pump, including the correctly rated 3-phase controller, across the coastal region and for agricultural clients further inland.

Specifications:

• Model: 4SP3-18
• Power: 1.5HP, three-phase AC
• Impeller: Stainless steel
• Outlet size: 1.25 inches
• Max flow: 4.2m³/h (4,200L/h)
• Max head: 112M
• Recommended depth: 0–96M
• Power source: 3-phase AC (grid or generator)
• Required controller: Matching 3-phase AC controller, 1.5HP/1.1KW rating
• Application: Domestic boreholes, household water points, light farm use

FAQs:

Does this pump run on solar power?
No — the 4SP3-18 is a three-phase AC pump requiring a stable 3-phase electricity supply. For solar-powered options, ask about DOYIN's DC or hybrid AD pump range.

What controller does this pump need?
It requires a matching 3-phase AC controller rated for 1.5HP/1.1KW — CoastalSolar Africa can supply and correctly match this.

How does this compare to the 4SP5-18 (2HP)?
The 4SP5-18 has a slightly larger 1.5" outlet and higher flow rate (6,600L/h vs 4,200L/h), but similar depth capability — the 4SP3-18 is the more compact, economical entry point into the stainless steel 3-phase range.

Is the stainless steel impeller worth it for coastal boreholes?
Yes, it offers better resistance to mineral content and mild salinity often found in coastal borehole water compared to ordinary impeller pumps.

Do you install 3-phase pumps in Kilifi and Malindi?
Yes, CoastalSolar Africa supplies and installs 3-phase submersible pumps like the 4SP3-18 across Mombasa, Malindi, Diani, Kilifi, Lamu, and inland agricultural areas with 3-phase power access.