ARCA MK Series - Technical Specifications of Prk Boilers

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2.3 TECHNICAL SPECIFICATIONS OF PRK BOILERS
− Steel boiler with pressurized combustion, for heating and hot water systems up to 95° C.
− Output: from 260 up to 3500 kW.
− Running : light oil and gas.
− Cylindrical furnace with flame inversion, detached from the back duct plate, arc-welded on a copper bar.
− Steel boiler body Fe 360 UNI EN 10025/92, completely electro-welded in a CO2 controlled atmosphere.
− Steel duct bundle Fe 360D UNI EN 10204/2.2, 4 mm thickness.
− Dispenser of the return water returning from the system towards the front duct plate allowing a better cooling and limiting carbonate and
magnesium deposits.
− Completely adjustable door allowing perfect combustion product tightness.
− Epoxy enamelled steel jacket with, and boiler body insulation by means of 80 mm thick glass fibre pad.
− The switchboard is outside the jacket and fitted with a manual reset thermostat, a thermometer, a minimal temperature thermostat, an
anti-inertia thermostat, a general switch, a circulating pump switch and a burner switch. Rubber sheath with IP40 minimal protection
level.
PRK 350 PRK 420 PRK 470 PRK 520 PRK 600
kW
kcal/h x 1000
260 ÷ 349
223,6 ÷ 300,14
300 ÷ 419
258 ÷ 360,34
380 ÷ 470
326,8 ÷ 404,2
400 ÷ 524
344 ÷ 450,64
470 ÷ 600
404,2 ÷ 516
kW
kcal/h x 1000
281 ÷ 379
241,6 ÷ 325,94
324 ÷ 457,8
278,6 ÷ 393,7
410 ÷ 510,5
352,6 ÷ 439,03
430 ÷ 571
369,8 ÷ 491,06
506 ÷ 654
435,1 ÷ 562,4
Combustion chamber volume m³ 0,293 0,293 0,39 0,39 0,467
kW/m³
kcal/h m³
1.293,5
1.112.410
1.562,4
1.343.664
1.308,9
1.125.654
1.464
1.259.040
1.400,4
1.204.344
Exchange surface m² 8,3 9,3 9,7 9,7 12
kW/m²
kcal/h m²
42
36.120
45
38.700
48,5
41.710
54
46.440
50
43.000
Smoke duct number n° 28 30 33 33 33
Smoke duct diameter Ø est. 1½” 1½” 1½” 1½” 1½”
Boiler weight kg 650 740 1.070 1.070 1.250
Water content lt. 340 400 470 470 570
Operating pressure bar 6 6 6 6 6
Hydraulic pressure bar 9 9 9 9 9
Max. operatine temperature °C 95 95 95 95 95
Water loss of heat ∆t=15°C mbar
24 38 19 23 32
Combustion chamber pressure mbar 2,4 3,6 3,8 4,1 4,8
Minimum efficiency at 100% % 89 89,2 89,2 89,2 89,2
Efficiency at 100% % 90,2 91,5 92 91,7 91,7
Minimum effciency at 30% % 87,6 87,8 87,8 87,8 87,8
Efficiency at 30% % 91,3 92,8 93,4 93 93
Loss of heat at the chimney with working burner % 7,38 7,8 7,45 7,65 7,65
Loss of heat at the chimney with burner out % 0,25 0,24 0,2 0,22 0,22
Loss of heat at the jacket ∆t=50°C %
0,62 0,7 0,55 0,65 0,65
Burner connection (Ø) mm 210 210 240 240 240
Flue connection (Ø) mm 250 250 300 300 300
Min. chimney depression mbar 0,2 0,2 0,2 0,2 0,2
Max smoke temperature °C 190 188 180 185 190
Smoke temperature in the output range °C 151 ÷ 190 147 ÷ 188 148 ÷ 180 151 ÷ 185 151 ÷ 190
CO
2
a gas % 9,8 9,7 10 9,9 9,9
CO a gas ppm 6 15 28 19 19
NOx a gas ppm 56 48 61 52 52
Max. light oil smoke flow rate m³/h 894 1.080 1.205 1.344 1.595
Max. methane smoke flow rate m³/h 790 967 1.064 1.200 1.447
Light oil burning air volume (practice) m³/h 489 590 658 735 842
Methane burning air volume (practice) m³/h 450 544 616 684 749
Combustion chamber dimensions (DiameterxLenght) mm
530 × 1.300 530 × 1.300 628 × 1.250 628 × 1.250 628 × 1.500
Thermostat adjustment range °C 55 ÷ 80 55 ÷ 80 55 ÷ 80 55 ÷ 80 55 ÷ 80
Output
Fornace output
Thermal load
Thermal output