Navien LCB700 Blue Flame Combi Boiler - Internal Model

LCB700 Blue Flame Combi – Internal Model

Our LCB700 Blue Flame range of oil boilers is the first in the UK market to offer an A+ energy rating, thanks to an exceptional design and the latest smart control systems.*

Combined with easy to install features, such as a combined PRV/condensate drain and flexible pipework arrangements, the LCB700 Blue Flame is a boiler like no other.

  • HVO compatible
  • 10-year parts and labour warranty as standard
  • Future proof Blue Flame technology delivers superior efficiency and ultra-low NOx emissions
  • Lightweight design for easy installation
  • Clean and modern design
  • Stainless steel heat exchangers for optimum durability and long term efficiencies
  • Flue venting up to 21m in horizontal and vertical arrangements
  • Flexible installation options thanks to compact design and flueing
  • Achieves highest 3-star mark in DHW performance (in accordance with EN Regulations)
  • 3-zone ready with Smart Plus control pack
  • Text driven integral display for intuitive control and fuel consumption figures
  • Class leading energy efficiency for reduced running costs

* An A+ energy rating is achieved when installed with 3 Smart Plus room thermostats.

Technical Data

21 - RS / LS / LC 28 - RS / LS / LC 36 - RS / LS / LC 21 - RSX / LSX / LCX 28 - RSX / LSX / LCX 36 - RSX / LSX / LCX
Heat Output 80/60°C 16/21kW 21/28kW 29/36kW 16/21kW 21/28kW 29/36kW
50/30°C 23.0kW 30.3kW 39.0kW 23.0kW 30.3kW 39.0kW
DHW Maximum Flow Rate (±15%) 14L/min 18L/min 20L/min 14L/min 18L/min 20L/min
DHW Control Range 30-60°C (Default 50°C)
Maximum hot water temperature rise for 90 litres draw off (@max flow rate) 40°C
Flue Flue Size Coaxial Plastic Ø 60/100
Max Horizontal Length 20m
Max Vertical Length 21m
Dimensions Combi Model 600 x 600 x 860mm 650 x 673 x 900mm
Weight Combi 91kg 98kg
ErP Efficiency ErP A (93%)
ErP Efficiency with Smart Plus ErP A+ (98%)
EN Regulation (EN13203-1)
NOx Emission Rate 57.2mg/kWh 57.2mg/kWh 63.2mg/kWh 57.2mg/kWh 62.5mg/kWh 63.2mg/kWh

LCB700 FAQs

What does the E302 fault code mean for the LCB700?

This means that the system pressure is too low and you may see that the system pressure gauge or the pressure reading on the front display indicates that the pressure in the system is below the 1 bar pressure. To re-pressurise the system you will find a filling loop (metal braided flexible hose) on a combi boiler version near the top right of the boiler with two tap connections at either end of the filling loop. Two small black tap handles.

The taps should be opened a quarter of a turn. Open one small black tap one and then open slowly the other small black one. The water will start to refill the system (water should be heard filling the system). You should see the pressure gauge or the reading on the front display rise back up between 1 bar and 1.2 bar pressure and then stop filling. Once the pressure gauge between 1 bar and 1.2 bar turn the taps back to the off position and the water will stop filling the system. The error code E302 will stop and the boiler will now operate. If the error code E302 is still active, fill up the system a little more but not over 1.5 bar.

(If you do fill the system too much and the pressure gauge is too high, just bleed water from a radiator until the pressure on the gauge goes down to below 1.2 bar).

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