Hot Water Boiler
Boilers
Hot Water Boiler
Model: WNS/CWNS Series
1. Product Overview
A hot water boiler uses hot water as its heat-transfer medium: fuel combustion raises the water to the rated temperature, providing a stable heat source for space heating, production processes, and domestic hot water. The WNS/CWNS series hot water boiler adopts a horizontal internal combustion three-pass structure with core components including shell, smoke tubes, and burner. Hot water circulates in a closed-loop system. The atmospheric type (CWNS) operates at atmospheric pressure, safe and reliable; the pressurized type (WNS) provides higher temperature hot water for different process requirements. Widely used in urban central heating, factory workshop heating, and hotel hot water supply.
Key Features
Rated thermal power 0.35–14 MW
Supply water temperature 95/115/130°C
Return water temperature 70°C
Thermal efficiency ≥95% (condensing type ≥98%)
Atmospheric/pressurized types available
Fully automatic intelligent control
Low NOx emissions, ≤30mg/Nm³
2. Working Principle
Hot Water Heating Principle
Fuel burns in the furnace producing high-temperature flue gas, which flows through three passes: first pass through corrugated furnace, second pass through threaded smoke tubes, third pass through smooth smoke tubes, transferring heat to the boiler water. The heated water is delivered to the points of use by circulation pumps. After releasing heat, the cooled water returns to the boiler through the return pipe for reheating, forming a closed-loop circulation. The system controls supply water temperature by regulating burner power and circulation flow rate.
Atmospheric vs. Pressurized
Atmospheric hot water boilers (CWNS) are open to the atmosphere at the top, operating at atmospheric pressure with water temperature not exceeding 95°C, offering high safety without special equipment registration. Pressurized hot water boilers (WNS) are sealed systems operating above atmospheric pressure, with water temperatures up to 130°C or higher, requiring special equipment management. Atmospheric type is suitable for general heating and hot water supply, while pressurized type is for high-temperature heating and long-distance transport.
3. System Classification
By Pressure
1. Atmospheric hot water boiler (CWNS) — operates at atmospheric pressure, exempt from special equipment registration
By Fuel
1. Gas-fired hot water boiler (natural gas, LPG)
By Structure
1. Horizontal internal combustion fire-tube boiler
4. Detailed Technical Parameters
4.1 Pressurized Type Main Parameters
| Parameter | Unit | WNS-0.35 | WNS-0.7 | WNS-1.4 | WNS-2.8 | WNS-4.2 | WNS-7 | WNS-14 |
|---|---|---|---|---|---|---|---|---|
| Rated thermal power | MW | 0.35 | 0.7 | 1.4 | 2.8 | 4.2 | 7 | 14 |
| Rated pressure | MPa | 0.7/1.0 | 0.7/1.0 | 0.7/1.0/1.25 | 0.7/1.0/1.25 | 1.0/1.25 | 1.0/1.25 | 1.25/1.6 |
| Supply water temp. | °C | 95/115 | 95/115 | 95/115/130 | 95/115/130 | 115/130 | 115/130 | 130/150 |
| Return water temp. | °C | 70 | 70 | 70 | 70 | 70 | 70 | 90 |
| Thermal efficiency | % | ≥95 | ≥95 | ≥96 | ≥96 | ≥96 | ≥96 | ≥96 |
| Gas consumption | Nm³/h | 36 | 72 | 144 | 288 | 432 | 720 | 1440 |
| Circulation flow | t/h | 12 | 24 | 48 | 96 | 144 | 240 | 480 |
| Dimensions (L×W×H) | m | 3.0×1.7×1.9 | 3.8×2.1×2.3 | 5.0×2.5×2.7 | 6.0×2.9×3.1 | 7.2×3.3×3.5 | 8.5×3.8×4.0 | 11.0×4.8×5.0 |
4.2 Atmospheric Type Main Parameters
| Parameter | Unit | CWNS-0.35 | CWNS-0.7 | CWNS-1.4 | CWNS-2.8 | CWNS-4.2 |
|---|---|---|---|---|---|---|
| Rated thermal power | MW | 0.35 | 0.7 | 1.4 | 2.8 | 4.2 |
| Supply water temp. | °C | 85/90 | 85/90 | 85/90 | 85/90 | 85/90 |
| Return water temp. | °C | 60/65 | 60/65 | 60/65 | 60/65 | 60/65 |
| Thermal efficiency | % | ≥95 | ≥95 | ≥96 | ≥96 | ≥96 |
| Gas consumption | Nm³/h | 36 | 72 | 144 | 288 | 432 |
5. Core Component Selection
| Component | Material/Spec | Recommended Brand | Remarks |
|---|---|---|---|
| Furnace | Q345R corrugated | — | Thermal expansion compensation |
| Smoke tubes | 20# threaded | — | Enhanced heat transfer |
| Burner | Gas/oil fired | Weishaupt/Baltur | Low NOx type |
| Circulation pump | Centrifugal/in-line | Grundfos/WILO | VFD optional |
| Control panel | PLC + touch screen | Siemens | Remote monitoring |
| Safety valve | Spring low-lift type | LESER | Pressurized type only |
| Expansion tank | Diaphragm/open type | — | System pressurization |
| Temp. sensor | PT100 RTD | WIKA | Accuracy ±0.5°C |
6. Typical Application Fields
| Industry | Application | Heating Requirement |
|---|---|---|
| Central heating | Residential/office heating | Supply 95–130°C, return 70°C |
| Industrial plants | Workshop heating, process hot water | Supply 95–115°C |
| Hotels | Domestic hot water, pool heating | Supply 60–85°C |
| Hospitals | Heating, domestic water, sterilization | Supply 85–95°C |
| Schools | Building heating, canteen hot water | Supply 85–95°C |
| Greenhouses | Agricultural heating | Supply 60–85°C |
7. Design Standards & Certification
Design Standards
GB/T 16508 — Fire-tube boiler standard
GB/T 16507 — Water-tube boiler standard
NB/T 47034 — Industrial boiler technical conditions
TSG 11 — Boiler safety technical regulations
Certification
ISO 9001 quality management system certification
Special equipment manufacturing license
Environmental product certification
CE certification (optional)
8. Customizable Options
| Option | Description | Remarks |
|---|---|---|
| Condensing economizer | Flue gas heat recovery | Efficiency ≥98% |
| Weather compensation | Outdoor temp. based control | Energy saving 15–20% |
| VFD circulation pump | Load-based flow control | Energy saving 30% |
| Multi-boiler cascade | Cluster management | Auto rotation |
| Remote monitoring | IoT cloud platform | Mobile access |
| SS heat exchanger | SUS316L material | Corrosion protection |
| Low noise design | Sound enclosure + silencer | ≤65dB |
| Integrated tank | Boiler + tank combined | Space saving |
9. Warranty Terms
Warranty period: 18 months from shipment or 12 months from commissioning (whichever comes first). Covers material or manufacturing defects. Does not cover consumables (seals, refractory materials, insulation) or damage from improper operation, water quality issues, or non-compliant installation.
Warranty Service Scope
Free replacement of defective parts
Free on-site diagnosis and repair
24/7 phone technical support
Discounted spare parts after warranty
10. Packaging & Delivery
| Item | Packaging | Transport Dims | Gross Weight |
|---|---|---|---|
| Boiler main unit | Weatherproof film + steel base | Per model | Unit +5% |
| Burner | Wooden crate | Per spec | Per spec |
| Control panel | Wooden crate + moisture barrier | 1.2×0.8×0.6m | ~60kg |
| Pump & valves | Wooden crate | Per spec | Per spec |
| Accessories | Wooden crate | 0.8×0.6×0.5m | ~30kg |
Lead time: 30–50 working days. Delivery terms: FOB/Shanghai. Documents: Certificate of conformity, operation manual, packing list.
11. Information Required for Inquiry
To prepare an accurate quotation, please provide:
| No. | Parameter | Description |
|---|---|---|
| 1 | Rated thermal power | MW or kcal/h |
| 2 | Supply/return water temperature | °C |
| 3 | Rated pressure | MPa (indicate if atmospheric) |
| 4 | Fuel type | Natural gas/diesel/electric |
| 5 | Fuel calorific value | kcal/Nm³ or kcal/kg |
| 6 | Heating area | m² |
| 7 | Building type | Residential/factory/hotel etc. |
| 8 | Installation location | Plant room/roof/outdoor |
| 9 | Power supply | V/Hz/phase |
| 10 | Other requirements | Weather compensation, remote monitoring, etc. |