VITOMAX 300-LT Heating output 1.86 to 5.90 MW
VITOMAX 300-LT Type M343B
Low pressure hot water boilers. Low NOx version. Certified in accordance with Gas Appliances Directive 2009/142/EC, approved for flow temperatures up to 110 °C. Certified in accordance with Pressure Equipment Directive 97/23/EC, approved for flow temperatures up to 120 °C, individual test certification only. Suitable for the combustion of fuel oil EL and gas. Three-pass boiler. Permissible operating pressure 6 bar.
Specification for burner selection
Note: All diagrams are schematic, illustrative examples.
Table 1: Boiler Size and Output
| Boiler size*1 | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
| Rated heating output*2 - for natural gas/fuel oil EL (MW) | 1.86 | 2.30 | 2.90 | 3.50 | 4.10 | 4.70 | 5.90 |
| Max. perm. combustion heating output - for natural gas/fuel oil EL (MW) | 2.01 | 2.49 | 3.14 | 3.79 | 4.43 | 5.08 | 6.38 |
Table 1: Flame Tube Dimensions and Burner Connections
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | ||
| Flame tube dimensions | ||||||||
| - Flame tube length to reversing chamber (a1) (mm) | 2466 | 2665 | 2867 | 3017 | 3134 | 3283 | 3608 | |
| - Flame tube length to the centre of the reversing chamber (a2) (mm) | 2670 | 2891 | 3121 | 3296 | 3439 | 3613 | 3974 | |
| - Total flame tube length (a3) (mm) | 2977 | 3227 | 3477 | 3677 | 3850 | 4050 | 4485 | |
| Diameter | ||||||||
| - Smooth pipe min. internal Ø (d1) (mm) | 866 | 926 | 994 | 1050 | 1110 | 1160 | 1238 | |
| Burner connections | ||||||||
| - Max. flame head (c) (mm) | 410 | 410 | 520 | 520 | 520 | 520 | 590 | |
| - Min. flame head length (e) (mm) | 265 | 265 | 265 | 265 | 265 | 265 | 270 | |
| Flame tube volume - Relative to flame tube length (a3) (m³) | 1.75 | 2.17 | 2.70 | 3.18 | 3.73 | 4.28 | 5.40 | |
Figure 1: Schematic diagram illustrating flame tube dimensions. Shows lengths a1, a2, a3, internal diameter d1, and burner connection dimensions c and e.
Table 2: Max. Pressure Drop on the Flue Gas Side*2
| Boiler size*1 | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
| - for natural gas (mbar) | 6.0 | 6.5 | 8.5 | 9.0 | 9.5 | 10.0 | 10.8 |
| - for fuel oil EL (mbar) | 5.5 | 6.0 | 7.9 | 8.2 | 8.5 | 9.0 | 9.8 |
*1 Last digit of part number
*2 For a flow/return temperature of 80/60 °C
Specification for boiler
Figure 2: Caution - hot surface. A multi-view technical drawing of the Viessmann Vitomax 300-LT boiler showing side, top, and front views with connection points and dimensions. Key labels include: A (Type plate), AGA (Flue outlet), BNA (Burner connection), E (Drain - DN 40 PN 40), HL (Handhole - 100 x 150 mm), KAB (Boiler cover), KOA (Condensate drain - connector R 1 1/2), KR (Boiler return), KTÜ (Boiler door), KV (Boiler flow). Also shows internal components and dimensions like o1, o2, o3, o4, o5, p1. An alternative boiler base with longitudinal I-beams (chargeable option) is depicted. Equipotential bonding is indicated.
Labels for Figure 2:
- A: Type plate
- AGA: Flue outlet
- BNA: Burner connection
- E: Drain - DN 40 PN 40
- HL: Handhole - 100 x 150 mm
- KAB: Boiler cover
- KOA: Condensate drain - connector R 1 1/2
- KR: Boiler return
- KTÜ: Boiler door
- KV: Boiler flow
- R1: Cleaning aperture, flue gas collector
- R2: Flame tube cleaning aperture
- SCH: Inspection port
- SIV: Safety valve connector
- STB: High limit safety cut-out - female connection R 1/2
- TR: Temperature controller - female connection R 1/2
- VZS: Intermediate flow piece as accessory - option for 110/120 °C boiler
- ?: Equipotential bonding
Table 3: Nominal Dimensions*3
| Boiler size*1 | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
| a (mm) | 1300 | 1395 | 1470 | 1540 | 1595 | 1670 | 1830 |
| b (mm) | 1000 | 1080 | 1160 | 1226 | 1260 | 1340 | 1475 |
| c (mm) | 610 | 665 | 700 | 740 | 775 | 810 | 900 |
| d (mm) | 777 | 807 | 857 | 881 | 980 | 990 | 1040 |
| e (internal)*4 (mm) | 346 | 346 | 392 | 440 | 490 | 550 | 620 |
| f (mm) | 900 | 900 | 900 | 900 | 1000 | 1000 | 1000 |
| g (mm) | 150 | 235 | 290 | 330 | 360 | 370 | 395 |
| h (mm) | 1765 | 1790 | 1790 | 1870 | 1935 | 2000 | 2130 |
| i (mm) | 210 | 210 | 210 | 210 | 260 | 260 | 260 |
| o1 (mm) | 1825 | 1950 | 2075 | 2175 | 2300 | 2400 | 2620 |
| o1 I-beam (mm) | 1985 | 2110 | 2235 | 2335 | 2540 | 2800 | 2860 |
| o2 (mm) | 3816 | 4066 | 4316 | 4516 | 4739 | 4939 | 5374 |
| o3 (mm) | 1320 | 1370 | 1420 | 1470 | 1580 | 1630 | 1730 |
| o4 (mm) | 2020 | 2110 | 2200 | 2300 | 2400 | 2500 | 2680 |
| o5 (mm) | 2370 | 2460 | 2550 | 2650 | 2750 | 2850 | 3030 |
| p1 (mm) | 845 | 908 | 970 | 1020 | 1044 | 1094 | 1202 |
| p1 I-beam (mm) | 765 | 828 | 890 | 940 | 924 | 894 | 1082 |
| q (mm) | 440 | 440 | 440 | 440 | 440 | 440 | 440 |
| r (mm) | 1120 | 1185 | 1265 | 1330 | 1400 | 1450 | 1540 |
| s (mm) | 2225 | 2315 | 2405 | 2505 | 2605 | 2705 | 2885 |
| t (mm) | 380 | 397 | 415 | 438 | 457 | 475 | 512 |
| u (mm) | 120 | 120 | 120 | 120 | 160 | 160 | 160 |
*3 Subject to modification
*4 Internal Ø + 8 mm (for sizes 0-2) and + 10 mm (for sizes 3-6) produces external Ø
Figure 3: Intermediate Flow Piece (Option)
Diagram illustrating an optional intermediate flow piece for 120°C boilers. It shows a cylindrical component with three connection points labeled A, B, and C.
- A: Connector for fitting assembly DN 20 PN 40
- B: Connector for electrode water level limiter DN 50 PN 40
- C: Female connections for thermometer, sampling valve and other control equipment 5 x R 1/2
| DN | 125 | 150 | 200 | 250 | 300 | 350 | 400 | |
| a (mm) | 500 | 500 | 500 | 550 | 550 | 600 | 600 |
Table 4: Boiler Size and Shipping Dimensions
| Boiler size*1 | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
| Permiss. flow temperature*5 (for permiss. op. pressure) (6 bar °C) | See "Permissible flow temperatures" on page 8 | ||||||
| Permiss. return temperature (°C) | See "Operating conditions" on page 7 | ||||||
| Shipping dimensions incl. packaging | |||||||
| - Total length (m) | 4.02 | 4.27 | 4.52 | 4.72 | 4.94 | 5.14 | 5.57 |
| - Total width (m) | 2.07 | 2.16 | 2.25 | 2.35 | 2.45 | 2.55 | 2.73 |
| - Total height (m) | 2.40 | 2.49 | 2.58 | 2.68 | 2.78 | 2.88 | 3.06 |
| Dry weight*6 boiler incl. thermal insulation (for permiss. op. pressure) (6 bar t) | 5.3 | 6.3 | 7.3 | 8.2 | 9.6 | 10.6 | 13.3 |
| Boiler water content (m³) | 5.0 | 5.5 | 6.4 | 8.2 | 9.3 | 10.5 | 13.0 |
| Connections for boiler | |||||||
| - for permiss. op. pressure (6 bar PN 16 DN) | 150 | 150 | 200 | 200 | 200 | 250 | 250 |
| Safety valve connector (6 bar PN 16 DN) | 50 | 50 | 65*7 | 65*7 | 65*7 | 80 | 80 |
| Flue gas mass flow rate | |||||||
| - for natural gas (t/h) | 1.5225 x combustion output in MW | ||||||
| - for fuel oil EL (t/h) | 1.5 x combustion output in MW | ||||||
| Flue gas side heating surface (m²) | 53 | 63 | 75 | 87 | 99 | 110 | 132 |
| Flue gas volume (m³) | 3.10 | 3.70 | 4.60 | 5.40 | 6.50 | 7.50 | 9.50 |
*1 Last digit of part number
*5 The maximum achievable flow temperature is approx. 15 K below the permissible flow temperature (= safety temperature)
*6 Deviations of 10 % are possible, subject to order
*7 4-hole version
Dia. 1: Pressure Drop on the Heating Water Side
A line graph titled "Pressure drop on the heating water side". The X-axis represents "Flow rate in m³/h" (ranging from 20 to 600). The Y-axis represents "Pressure drop in mbar" (ranging from 0 to 200). Three lines labeled A, B, and C are plotted, representing different connector sizes (DN 150, DN 200, DN 250 respectively).
Connectors for boiler flow and return: A: DN 150, B: DN 200, C: DN 250
Dia. 2: Flue Gas Temperature and Boiler Efficiency
A line graph titled "Flue gas temperature and boiler efficiency". The X-axis represents "Boiler heating output in % relative to the maximum possible rated heating output" (ranging from 40 to 100). The left Y-axis shows "Flue gas temperature in °C" (for gas and oil, ranging from 100 to 190). The right Y-axis shows "Boiler efficiency in %" (for oil and gas, ranging from 92 to 97). Four lines labeled A, B, C, and D represent different measurements:
- A: Flue gas temperature in °C (at 60/40 °C boiler water temperatures)
- B: Boiler efficiency in % (at 60/40 °C boiler water temperatures)
- C: Flue gas temperature in °C (at 80/60 °C boiler water temperatures)
- D: Boiler efficiency in % (at 80/60 °C boiler water temperatures)
Subject to boiler heating output.
■ Residual oxygen content in the flue gas: 3 %
Specification
Minimum Clearances
Figure 3: Diagram illustrating minimum clearances around the boiler. It shows a top-down view of the boiler with clearance zones labeled a, b, c, d, e, f, o2, o4. The diagram also shows labels for boiler components: A (Steam boiler or hot water boiler), B (Burner), C (Regulating and control system), D (Option: anti-vibration supports).
| Clearance | Value |
| a | ≥ 1000 mm |
| b | ≥ 500 mm |
| c | ≥ 800 mm |
| d | ≥ 500 mm |
| e | ≥ 300 mm |
| f*8 | ≥ 500 mm |
| o2, o4 | Max. length, max. width |
Observe risk warnings and the information provided. Observe the given dimensions to ensure easy installation and maintenance. The minimum clearances must be observed.
Reducing Noise
Place anti-vibration supports (not included in standard delivery) under the boiler shell. Position supports evenly over the length and centrally underneath the base rails.
Siting Conditions
- Prevent air contamination from halogenated hydrocarbons. Halogenated hydrocarbons can be found in sprays, paints, solvents and cleaning agents. If there is a risk of air contamination from halogenated hydrocarbons where the boiler is sited, an adequate supply of uncontaminated combustion air must be provided.
- Avoid very dusty conditions
- Avoid high levels of humidity
- Prevent frost and ensure good ventilation
- Site on a level surface. Impact can cause system faults and damage.
Delivered Condition
Boiler
- Boiler shell with burner connection flange and burner plate supplied
- Fitted boiler door/doors
- Bolted down cleaning cover
- Fitted load bearing boiler cover
- Fitted thermal insulation and thermally insulated flue gas collector
- Turbulators (if installed)
- Turbulator extractor (if turbulators are installed)
- Packaging
Boiler accessories (option)
- Flue gas/water heat exchanger
- Regulating and control systems
- Safety equipment
- Burner
- Platform
- Intermediate flow piece as an accessory (required for ≥ 120 °C)
- Valves/fittings
Control Unit Versions
For single boiler system (With burner control panel)
- Vitotronic 100: For operation with a constant boiler water temperature or for a modulating boiler water temperature in conjunction with a control panel or an external control unit
- Vitotronic 200: For modulating boiler water temperature. For modulating boiler water temperature with mixer control up to 2 heating circuits
For a single and multi boiler system (With Vitocontrol control panel)
- For constant or modulating boiler water temperature
- Implementation of boiler sequence control and regulating or un-regulated heating circuits including DHW heating according to customer requirements
*8 Leave one boiler length of space clear in front of the boiler door. This makes it easier to remove the turbulators and clean the boiler.
Operating Conditions
For water quality requirements, see the "Standard values for water quality" section.
Table 5: M343B Operating Conditions*9
| Operation with burner load | ≥ 60 % | < 60 % | |
| Requirements | Requirements | ||
| 1. Heating water flow rate | Oil operation: Gas operation: | 38 °C 45 °C | 53 °C 53 °C |
| 2. Boiler return temperature*9 (minimum value) | Oil operation: Gas operation: | 50 °C 60 °C | 60 °C 65 °C |
| 3. Lower boiler water temperature | |||
| 4. Two-stage burner operation | Stage 1: 60% of rated heating output | No minimum load required | |
| 5. Modulating burner operation | Between 60 and 100% of rated heating output | ||
| 6. Reduced mode | Single boiler systems: Multi boiler systems: | operation with the lower boiler water temperature Lead boiler: operation with the lower boiler water temperature | |
| 7. Weekend setback | As per reduced mode | Lag boiler: can be shut down | |
Design Information: Burner Selection
See:
- "Specifications for burner selection" chapter
- Burner specification
Criteria for burner selection:
- Burner must be selected in accordance with the combustion heating output and the pressure drops on the flue gas side
- Burner must be selected in accordance with the current flue gas standards
- Burner head must be suitable for operating temperatures of at least 500 °C
Note: The minimum flame head length must be maintained.
Burner Type
- Pressure-jet oil burner
- Pressure-jet gas burner
Requirements:
- Test and identification in accordance with DIN EN 267
- Test to DIN EN 676
- CE designation in accordance with Directive 2009/142/EC
Burner Connection
Preparing the burner plate - 2 options (M)
- M 1: At the factory (by Viessmann)
a) If the burner is supplied by Viessmann: commission Viessmann to carry out the preparatory work.
b) If the burner is not supplied by Viessmann: proceed as in (a), stating the burner type and make. - M 2: On site
If the burner plate is being adapted by the customer: create the flame tube aperture and fixing holes in the blank plate supplied. To ensure correct burner operation, comply with the boiler manufacturer's specification for the flame head length.
Fuels
- Oil
- Fuel oil EL to DIN 51603 part 1
- Bio diesel: To DIN EN 51603-6, EN 14213, EN 14214 (or similar)
- Gas
- Natural gas, town gas and LPG according to DVGW Code of Practice G 260/I and II or local regulations
- Alternative fuels on request
*9 For an installation example of a return temperature raising facility, see "System examples" in the technical guide.
Design Information (cont.)
Permissible Flow Temperatures
Hot water boiler for permissible flow temperatures (= safety temperatures):
- Up to 110 °C
Identification: in accordance with Gas Appliances Directive 2009/142/EC - Up to 120 °C (by means of individual test certification only)
Identification: in accordance with Pressure Equipment Directive 97/23/EC - Install additional safety equipment for operation with a safety temperature of 120 °C
- According to the Health & Safety at Work Act [Germany], these boilers require supervision. In accordance with conformity assessment diagram no. 5 of the EU Pressure Equipment Directive, these boilers must be classed as category IV.
- Assembly, installation and operation are subject to approval by the appropriate local authority [check local regulations].
- The system must be tested prior to commissioning.
- External inspection annually.
- In place of an internal inspection, a pressure test at least every 3 years.
- Inspections may only be carried out by an approved inspection body, e.g. TÜV.
Further information on design/engineering: See the technical guide to this boiler.
Tested Quality
CE designation according to current EC Directives.
Contact Information
Viessmann Werke GmbH&Co KG
D-35107 Allendorf
Telephone: +49 6452 70-0
Fax: +49 6452 70-2780
www.viessmann.com
Viessmann Limited
Hortonwood 30, Telford
Shropshire, TF1 7YP, GB
Telephone: +44 1952 675000
Fax: +44 1952 675040
E-mail: info-uk@viessmann.com
Subject to technical modifications.
