Vacuum hot water boiler

KDNV series in the small capacity type, KDNV series in the large capacity type

The KDNV vacuum hot water boiler encloses a fixed amount of heating medium water and keeps it in a vacuum (negative pressure) state in the boiler body. When the medium water is heated, it immediately evaporates into decompressed steam to indirectly heat the heat exchanger to provide hygienic water

Main specifications

Full specification table
ModelKDNV-10 ~ KDNV-300 · 19 models
Rated heat output0.12 – 3.49 MW (100,000 – 3,000,000 kcal/h)
Efficiency91% or more
Control methodON - OFF · HI - LOW - OFF
Power220V x 1ø x 60Hz · 380V x 3ø x 60Hz

Operating principle and features

  • Fuel cost reduction with high efficiency furnace design

    The high efficiency body design, which adopts once-through characteristics of the water tube boiler, forms the water cooling wall structure and heat absorbing 3-pass structure, greatly reduces fuel costs.

  • Easy handling, no license and inspection required

    Anyone can operate The KDNV vacuum hot water boiler as it is exempt from all laws and regulations in Korea (By law, the boiler is viewed as explosion-free boiler as it operates below atmospheric pressure). No license or inspection are required for operation.

  • Easy maintenance

    Attaching the artificial intelligence D-Brain enables the easier operation and management. (Option)

  • Absolutely safe design

    Unlike pressure boilers, the KDNV vacuum hot water boiler operates under negative pressure (pressure below atmospheric pressure) and has no risk of explosion. 4-level safety devices (Vacuum pressure, over heat prevention, boiler body thermistor and low water level switches) further ensures the reliability of the product.

  • Semi-permanent life

    As the boiler water (heating medium water) of the vacuum hot water boiler is always kept in a fixed amount under vacuum condition without moving, there are no risks of corrosion or scale accumulation caused by dissolved oxygen. In addition with hygienic high corrosion resistant stainless steel heat exchangers, the boiler body is semi-permanent.

  • Multi-purpose heat exchangers

    Heat exchangers can be used for heating, hot water supply and circulation heating in 1~3 circuits depending on the user’s demand. Each heat exchanger is independently installed and provides hygienic water without water mixing.

  • Low NOx Burner

    Fuel cost can be saved by attaching a low NOx burner and 40ppm or less of NOx is guaranteed when operating under 4% of O2

Helium gas leak detector

Check any leakage after processing the boiler body → Check any leakage after assembling the heat exchanger→ Check any leakage after assembling the finished product

Vacuum hot water boiler Helium gas leak detector figure
Vacuum hot water boiler Helium gas leak detector figure

Standard specifications

KDNV series in the small capacity type, KDNV series in the large capacity type

Standard specifications for vacuum hot water boiler KDNV series

Category Unit KDNV- 10 KDNV- 15 KDNV- 20 KDNV- 25 KDNV -30 KDNV- 35 KDNV- 40 KDNV- 45 KDNV- 50 KDNV- 60 KDNV- 80 KDNV-100 KDNV-120 KDNV-130 KDNV-150 KDNV-160 KDNV-200 KDNV-250 KDNV-300
Boiler specifications Rated heat output MW 0.12 0.17 0.23 0.29 0.35 0.41 0.47 0.52 0.58 0.70 0.93 1.16 1.40 1.51 1.74 1.86 2.33 2.91 3.49
kcal/h 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000 600,000 800,000 1,000,000 1,200,000 1,300,000 1,500,000 1,600,000 2,000,000 2,500,000 3,000,000
Efficiency % 91% or more
Heating area ㎡ 5.43 5.85 8.28 8.28 10.09 10.09 12.04 12.04 18 18 20 22 22 24 28 28 36 38 42
Control method - ON - OFF HI - LOW - OFF
Total power consumption kW 0.3(0.25) 0.3(0.35) 0.47(0.47) 0.47(0.47) 0.84(0.84) 1.2(1.2) 1.6(1.2) 2.3(1.9) 2.3(3.1) 4.1(3.1) 4.1(7.6) 11(7.6) 15(7.6) 18.5(11.1)
Power V 220V x 1ø x 60Hz 380V x 3ø x 60Hz
Retained heating medium water volume L 200 220 300 330 390 400 470 480 500 550 650 700 750 790 830 900 1,300 1,600 1,900
Fuel consumption LNG N㎥/h 11.0 16.5 22.0 27.5 33.0 38.5 44.0 49.5 54.9 65.9 87.9 109.9 131.9 142.9 164.8 175.8 219.8 274.7 329.7
Propane(LPG) 4.9 7.4 9.8 12.3 14.7 17.2 19.6 22.1 24.5 29.4 39.2 49.1 58.9 63.8 73.6 78.5 98.1 122.6 147.2
Butane 3.7 5.6 7.5 9.3 11.2 13.0 14.9 16.8 18.6 22.4 29.8 37.3 44.7 48.4 55.9 59.6 74.5 93.1 111.8
Diesel kg/h 10.7 16.0 21.3 26.7 32.0 37.3 42.7 48.0 53.3 64.0 85.4 106.7 128.0 138.7 160.0 170.7 213.4 266.7 320.1
Connection diameter Oil inlet A 15 15 15 15 15 15 15 15 15 15 25 25 25 25 25 25 25 25 25
Gas inlet 25 25 25 40 40 40 40 40 40 40 40 40 40 40 50 50 50 65 65
Flue ømm 200 200 200 200 250 250 250 250 300 300 350 350 350 400 400 400 500 550 600
Base size Width(W) mm 1,060 1,060 1,200 1,200 1,300 1,300 1,450 1,450 1,140 1,140 1,440 1,510 1,510 1,510 1,530 1,530 1,790 2,100 3,100
Length(L) 1,060 1,060 1,200 1,200 1,300 1,300 1,450 1,450 2,500 2,730 2,260 2,260 2,260 2,260 2,560 2,560 2,870 3,400 3,800
Height(H) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100
External size (Gas) Width(W) mm 860 860 1,000 1,000 1,100 1,100 1,250 1,250 1,140 1,140 1,440 1,510 1,510 1,510 1,530 1,530 1,890 2,000 2,180
Length(L) 1,370 1,370 1,640 1,640 1,740 1,810 2,000 2,000 3,270 3,570 3,610 3,640 3,640 3,690 3,960 3,960 4,730 5,120 5,280
Height(H) 1,640 1,640 1,870 1,870 1,900 1,900 1,920 1,920 1,570 1,570 2,170 2,340 2,340 2,340 2,530 2,530 2,580 2,720 2,860
External size (Diesel) Width(W) mm 860 860 1,000 1,000 1,100 1,100 1,250 1,250 1,140 1,140 1,440 1,510 1,510 1,510 1,530 1,530 1,890
Length(L) 1,350 1,350 1,530 1,530 1,630 1,730 1,940 1,940 3,150 3,390 3,230 3,370 3,370 3,420 3,710 3,710 4,510
Height(H) 1,640 1,640 1,870 1,870 1,900 1,900 1,920 1,920 1,570 1,570 2,170 2,340 2,340 2,340 2,530 2,530 2,580
Product weight kg 500 520 700 720 870 900 1,100 1,150 1,250 1,900 2,750 3,320 3,500 3,820 4,250 4,500 5,200 5,650 6,800

The external size may vary depending on the control panel and burner specifications.
Specifications in ( ) are diesel boiler specifications.

For heating and hot water circulation (333K → 343K) {60℃ → 70℃}

Category Unit KDNV -10 KDNV -15 KDNV -20 KDNV -25 KDNV -30 KDNV -35 KDNV -40 KDNV -45 KDNV -50 KDNV -60 KDNV -80 KDNV -100 KDNV -120 KDNV -130 KDNV -150 KDNV -160 KDNV -200 KDNV -250 KDNV -300
For heating and hot water circulation Rated heat output MW 0.12 0.17 0.23 0.28 0.35 0.41 0.47 0.52 0.58 0.7 0.93 1.16 1.40 1.51 1.74 1.86 2.33 2.01 3.49
kcal/h 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000 600,000 800,000 1,000,000 1,200,000 1,300,000 1,500,000 1,600,000 2,000,000 2,500,000 3,000,000
Circulation volume ℓ 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 60,000 80,000 100,000 120,000 130,000 150,000 160,000 200,000 250,000 300,000
Maximum operating pressure MPa{kgf/㎠} 1{10}
Pressure loss MPa{mH2O} 0.012{0.12} 0.017{0.17} 0.02{0.2} 0.018{0.18} 0.022{0.22} 0.03{0.3} 0.033{0.33} 0.022{0.22} 0.03{0.3} 0.033{0.33} 0.035{0.35} 0.04{0.4}
Material - Stainless steel pipe
Connection diameter A 40 40 50 50 50 50 65 65 80 80 80 100 100 100 100 100 150 150 150

For hot water supply (298K → 338K) {25℃ → 65℃}

Category Unit KDNV -10 KDNV -15 KDNV -20 KDNV -25 KDNV -30 KDNV -35 KDNV -40 KDNV -45 KDNV -50 KDNV -60 KDNV -80 KDNV -100 KDNV -120 KDNV -130 KDNV -150 KDNV -160 KDNV -200 KDNV -250 KDNV -300
For hot water supply Rated heat output MW 0.12 0.17 0.23 0.28 0.35 0.41 0.47 0.52 0.58 0.7 0.93 1.16 1.40 1.51 1.74 1.86 2.33 2.01 3.49
kcal/h 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000 600,000 800,000 1,000,000 1,200,000 1,300,000 1,500,000 1,600,000 2,000,000 2,500,000 3,000,000
Circulation volume ℓ 2,500 3,750 5,000 6,250 7,500 8,750 10,000 11,250 12,500 15,000 20,000 25,000 30,000 32,500 40,000 40,000 40,000 62,500 75,000
Maximum operating pressure MPa{kgf/㎠} 1{10}
Pressure loss MPa{mH2O} 0.06{0.06} 0.015{0.15} 0.018{0.18} 0.015{0.15} 0.02{0.2} 0.024{0.24} 0.033{0.33} 0.022{0.22} 0.03{0.3} 0.022{0.22} 0.035{0.35} 0.04{0.4}
Material - Stainless steel pipe
Connection diameter A 40 40 40 40 40 40 50 50 50 50 65 65 65 65 80 80 80 100 100

For hot water supply (278K → 338K) {5℃ → 65℃}

Category Unit KDNV -10 KDNV -15 KDNV -20 KDNV -25 KDNV -30 KDNV -35 KDNV -40 KDNV -45 KDNV -50 KDNV -60 KDNV -80 KDNV -100 KDNV -120 KDNV -130 KDNV -150 KDNV -160 KDNV -200 KDNV -250 KDNV -300
For hot water supply Rated heat output MW 0.12 0.17 0.23 0.28 0.35 0.41 0.47 0.52 0.58 0.7 0.93 1.16 1.40 1.51 1.74 1.86 2.33 2.01 3.49
kcal/h 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000 600,000 800,000 1,000,000 1,200,000 1,300,000 1,500,000 1,600,000 2,000,000 2,500,000 3,000,000
Circulation volume ℓ 1,667 2,500 3,333 4,167 5,000 5,833 6,667 7,500 8,333 10,000 13,333 16,667 20,000 21,667 25,000 26,667 33,333 41,667 50,000
Maximum operating pressure MPa{kgf/㎠} 1{10}
Pressure loss MPa{mH2O} 0.06{0.06} 0.015{0.15} 0.018{0.18} 0.015{0.15} 0.02{0.2} 0.024{0.24} 0.033{0.33} 0.022{0.22} 0.03{0.3} 0.022{0.22} 0.035{0.35} 0.04{0.4}
Material - Stainless steel pipe
Connection diameter A 40 40 40 40 40 40 50 50 50 50 65 65 65 65 80 80 80 100 100

The above specification table is indicated as follows.
- The fuel calorific value of fuel consumption is based on the low-level calorific value.
- LNG : 10,000 kcal/N㎥
- LPG(Propane) : 22,400 kcal/N㎥
- LPG(Butane) : 29,500 kcal/N㎥
- Diesel:10,300 kcal/kg(gravity:0.836)
Design flow temperature condition for heating and hot water circulation 333~343K {60~70℃}
Design flow temperature condition for hot water supply 298~338K {25~65℃}, 278~338K {5~65℃}
The rated heat output for heating and hot water supply is given for each individual use, and in the case of simultaneous use, the total is the boiler heat output.
The following tolerances are included due to the measurement errors of the measuring instrument or measuring personnel.
- Boiler efficiency measurement error ±1%
The above boiler efficiency is based on the true heat generation (low heat generation).
The above specification table is subject to change without notice.
This specification is based on a gas boiler. For detailed specifications, refer to the specification table.

Consultation and quotes

Tell us where the boiler will be installed and what it is for.
Our engineers will get back to you.