Horizontal Three Pass Wet Back Boiler
WNS gas/oil boiler adopts horizontal fire tube structure, which can provide larger steam/water output. Three pass wet-back design, larger corugated furmace, thread smoke tube with unique expansion welding technique, high quality and environmental protection.
| Output: | Steam, Hot-water |
| Capacity: | 0.1ton-40ton, 100kg-40000kg, 99kw-28000kw |
| Work Pressure: | 3-38bar, 0.3-3.8Mpa |
| Heat Temperature: | 0-450℃ |
| Applied Industry: | Food, Beverage, Feed, Textile, Paper, Chemical, Package, Refinery, Pharm, Building Material, Hotel... |
Introduction
WNS series boiler is a fully automatic, three-pass, wet-back fire tube boiler, burn gaseous and liquid fuels such as natural gas, LPG, diesel, and light/heavy oil. WNS stands for horizontal (W), wet-back (N), and three-pass internal combustion (S) – widely recognized for high efficiency and compact footprint.
This boiler uses a corrugated furnace tube as the first pass, threaded smoke tubes for the second and third passes. Integrated burner manages fuel supply, air‑fuel ratio, and ignition, PLC panel monitors water level, steam pressure, and flame condition with safety interlocks.
Therefore, this boiler is an ideal choice for industrial plant & comercial that need clean, and reliable steam/hot water.
1. Fully automatic operation – Touchscreen or push-button control.
2. Corrugated furnace tube – Increases heat absorption and compensates thermal expansion.
3. Wet-back three-pass design – The flame reversal chamber is surrounded by water, achieves high thermal efficiency without refractory wear.
4. Threaded smoke tubes – Create turbulence for better heat transfer than smooth tubes.
5. Large water volume – Handles sudden load changes and provides safety during power outages.
6. Low emissions – With low-NOx burner, NOx can be reduced to 30 mg/m³.
7. Safe and reliable – Multiple interlocks for water level, pressure, and flame; includes safety valves and explosion door.
8. Skid-mounted package – Delivered as a complete unit; only connect water, power, and fuel on site.
Configuration
Each gas/oil fired boiler is delivered as a packaged unit and includes:
① Boiler body ② PLC control cabinet ③ Top-brand burner ④ Water treatment & tank ⑤ Pressure gauge and pressure controller ⑥ Safety valves ⑦ Blowdown valves ⑧ Feedwater pump ⑨ Chimney with rain cap ⑪ Steam header ⑫ Economizer
Optional Upgrades: RO Water Treatment Equipment, Condenser, Low-NOx burner, Remote monitoring module, Frequency-controlled feed pump, Deaerator
Parameter
| Boiler Model | WNS0.5 | WNS1 | WNS1.5 | WNS2 | WNS3 | WNS4 | WNS5 | WNS6 | WNS8 | WNS10 | WNS15 | WNS20 | |
| Rated Capacity (ton/h) | 0.5 ton | 1ton | 1.5ton | 2ton | 3ton | 4ton | 5ton | 6ton | 8ton | 10ton | 15ton | 20ton | |
| Rated steam pressure | 1.0Mpa/1.25Mpa/1.6Mpa/2.0mpa/2.5Mpa | ||||||||||||
| Rated steam temperature | 184℃ /194℃/204℃/212℃/225℃ | ||||||||||||
| Boiler thermal efficiency | >98% | ||||||||||||
| Fuel consumption | Natural gas | 35.7 | 70.1 | 105.2 | 140.3 | 212.1 | 283.4 | 350.5 | 424.2 | 566.3 | 707.8 | 1061.7 | 1415.8 |
| Diesel | 32.5 | 64.6 | 48.75 | 129.3 | 192.9 | 258.2 | 323 | 388.6 | 514.6 | 641.7 | 960.1 | 1276.2 | |
| Boiler heating area | Boiler body(m2) | 10.64 | 21.71 | 37.25 | 51.8 | 74.49 | 98.1 | 122.8 | 156.91 | 204.83 | 229.6 | 383.81 | 454.8 |
| Economizer(m2) | 9.38 | 15.6 | 20.13 | 26.84 | 40.26 | 53.68 | 62.4 | 65.3 | 65.61 | 127.6 | 324.3 | 672 | |
| Largest transportation size(mm) | 3000 | 3450 | 3560 | 3930 | 4124 | 4680 | 5970 | 6455 | 6519 | 7000 | 7550 | 8200 | |
| 1500 | 1930 | 2140 | 2380 | 2332 | 2435 | 2360 | 2435 | 2736 | 3110 | 3336 | 3650 | ||
| 1810 | 2370 | 2580 | 2701 | 2757 | 2870 | 2796 | 2865 | 3139 | 3745 | 3575 | 4100 | ||
| Largest transporation weight(ton) | 3.5 | 5.5 | 6.5 | 8 | 10.7 | 11.6 | 13.5 | 17.5 | 22.5 | 26.8 | 35.2 | 45.5 | |
| Note: 1. Custom boiler design provided. 2. Specifications are subject to change without prior notice due to technical improvements. | |||||||||||||
| Model |
Rated heating capacity (mw) |
Rated working pressure (Mpa) |
Output water temperature (℃) |
Return water temperature (℃) |
Fuel consumption | |
| Light diesel oil(kg/h) | Natural gas(Nm3/h) | |||||
| WNS 0.35 | 0.35mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 31.6 | 36.6 |
| WNS 0.7 | 0.7mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 60.4 | 69.3 |
| WNS 1.4 | 1.4mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 122.8 | 146.1 |
| WNS 2.1 | 2.1mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 192.3 | 227.1 |
| WNS 2.8 | 2.8mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 246.1 | 286.5 |
| WNS 4.2 | 4.2mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 367.1 | 412.6 |
| WNS 5.6 | 5.6mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 490.2 | 543.7 |
| WNS 7.0 | 7.0mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 593.6 | 660.7 |
| WNS 10.5 | 10.5mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 936.5 | 998.8 |
| WNS 14 | 14mw | Atmospheric pressure/0.7/1.0/1.25/1.6 | 85~130 ℃ | 70/60 ℃ | 1200.8 | 1330.7 |
| Note: for place limited, we didn't list all models, if you need other capacity, pressure, fuel, please send us inquiry directly, we will send you detailed parameter. | ||||||
Characteristics
01
Multiple Safety Devices
①Anti-dry heating system with five stages water level check; ②Four stages pressure protection; ③Explosion-proof door with fire viewer; ④Remote monitoring system.
02
Double 12cm thickness aluminum silicate insulation layer
Assure the boiler surface temperatureis below 30°C, safety to boiler operator, and good work condition in boiler room, and great reduce heat loss.
03
Spirally corrugated furnace & Wet back structure
(1)Increased 10% heating area, avoid damaged by heat expansion. (2)Reduce the back tube sheet temperature and protect it from cracking.
04
Finned tube design economizer with aluminum silicate insulation
Increase 40°C to the feed water before boiler,reduce exhaust smoke temperature below 95 C,save fuel at least 6% per hour.
About Us
■ Founded in 1956, a premium supplier assessed, certified, and inspected by SGS Group. Leading industrial boiler manufacturer in China.
■ Holds international boiler certifications: CE, ASME, DOSH, EAC, GOST, ISO
■ Over 17 years of export experience, gold-level supplier, ensuring payment and delivery.
■ Professional team integrating R&D, production, sales, and service.
■ 53,053㎡ Factory area, supporting video/VR factory audits or third-party inspections.
■ Engineers serving over 50 countries.
■ Products sold to over 130 countries/regions, covering food, beverage, textiles, paper, wood industries. Serving over 100,000 customers.
Pre-sale Service:
1. Design一We help customer to choose the best boiler model according to the different requirements of different industries.
2. Drawing and files一Supply quality certificates, factory-inspect, fuel consumption calculation, cost analysis, foundation drawings, layout drawings, boiler room drawings nased on your needs, etc.
3. Technical Solution一Design completed boiler system with accessories and installation materials for your company.
4. Transportation一We have shipping partners and forwarder for lowest price and safe.
After-sale Service:
1. Provide a full range of boiler and original spare parts.
2. Overseas engineers installation and commissioning service is available.
3. Training in site, to ensure safe operation.
4. 24 hours online, quick respond.
5. Free maintenance and repair for one year and lifetime service.
If you require any boiler information or price, please feel free to let us know—no obligation.
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