iW Solar builds the SP-C pre-heated solar water heater in Taian City, Shandong Province — from 15 to 30 vacuum tubes and 120 L to 230 L net capacity. A copper coil heat exchanger keeps your customer's water separate from the solar loop, so hard or poor-quality water never enters the tank — B2B manufacturing and OEM & ODM for importers and distributors since 2013.
An integrative copper coil solar water heater is a compact, all-in-one pressurized system: collector and tank mounted together, with a copper coil heat exchanger inside the tank. The solar loop heats the water in the tank; your customer's tap water flows through the coil and is heated as it passes — the two waters never touch.
iW Solar manufactures the SP-C series from 15 to 30 vacuum tubes, covering 120 L to 230 L net capacity. Because the user's water stays inside the copper coil, there is no risk of corrosion or scale deposit in the system — which makes it the go-to pressurized model for regions with hard or inferior water quality.
Sunlight heats the tank; the coil turns it into pressurized hot water on demand:
Six standard configurations; heat transfer area scales with the tube count.
| Model | Vacuum tubes | Net tank capacity | Gross capacity | Heat transfer area |
|---|---|---|---|---|
| SP-C-15 | 15 pcs | 120 L | 155 L | 0.75 / 1.50 m² |
| SP-C-18 | 18 pcs | 140 L | 185 L | 1.13 / 2.26 m² |
| SP-C-20 | 20 pcs | 155 L | 205 L | 1.13 / 2.26 m² |
| SP-C-24 | 24 pcs | 185 L | 245 L | 1.32 / 2.64 m² |
| SP-C-25 | 25 pcs | 195 L | 255 L | 1.32 / 2.64 m² |
| SP-C-30 | 30 pcs | 230 L | 305 L | 1.32 / 2.64 m² |
| Item | Specification |
|---|---|
| Inner tank material | SUS304-2B (SUS316L optional) |
| Outer tank material | SUS304 / colour steel plate |
| Insulation | Polyurethane, 55 mm high-pressure foaming |
| Heat-transfer coil | Copper or SUS304, Φ12 mm / Φ20 mm |
| Vacuum tube | Φ58 × 1,800 mm, high borosilicate glass 3.3 |
| Frame | Galvanized steel, 2 feet or 3 feet |
| Mounting angle | 45° |
| Backup heating | Electric heater, auxiliary |
| Water quality | No corrosion or scale deposit on the user side — suited to inferior water areas |
| Quality control | Full-process inspection; tank pressure test; AQL 2.5 packing check; third-party inspection welcome |
All three are compact thermosiphon systems — the difference is how your customer's water gets hot. The copper coil (SP-C) heats tap water instantly through the coil and is the safest pick where water is hard or poor quality. The SD-P double inner tank heater stores pressurized hot water ready to draw, ideal where city pressure is stable. The non-pressure heater stays the budget champion where gravity flow is acceptable.
For markets with hard freezing winters, or when the tank must sit indoors, move to a split system — start from our heat pipe solar collector. For a side-by-side view of all main system types, read the different types of solar water heaters.
iW Solar is a B2B manufacturer, not a retail shop, so the heater is built around your business:
See the full solar water heater product range for the pressurized, split and flat plate options that complete a catalogue.
The user's water only passes through the copper coil and never sits in the tank, so scale and corrosion in the tank cannot reach the tap side. There is no risk of corrosion or scale deposit on the user side — the catalog design intent for inferior water areas.
Yes. The coil is connected directly to the city water line, so hot water comes out at tap pressure — the system takes advantage of the tap water pressure without any pump.
Copper gives the best heat transfer and is the standard choice; SUS304 is the economical alternative. Both are available in Φ12 mm and Φ20 mm, and we configure the coil for your water quality and price target.
An auxiliary electric heater keeps the water hot. The system runs completely automatically, so the household always has hot water regardless of weather.
Yes. Logo printing on the outer tank, custom cartons and manual branding are standard OEM services, and the outer tank can be finished in SUS304 or colour steel to your market preference.
MOQ starts from 1 set for market testing. Production takes 18–25 working days after order confirmation, and we reply to every enquiry within 12 hours.
Tell us your target market, target retail price and estimated annual quantity. Our engineers will come back with the right tube and coil configuration, and a price, within 12 hours.
Request a quotation See all solar water heater productsCompetitive pricing, exceptional quality — get a factory quote within 12 hours.
If you are looking for an experienced and reliable factory for your OEM custom solar water heaters and bespoke solar equipment in China, iWSOLAR is your best choice. We offer the most reasonable price with the finest quality to support your business.
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