NBE RTB PHOENIX v16.0 - PREVENTING FLUE GAS CONDENSATION; High chimney> 5 m.; Small cleaning in the chimney 125 mm - 150 mm.; Short un-insulated smoke pipe < 0,5 m.

When a boiler has an extremely high efficiency >93 %, the temperature of the flue gas is naturally low. Typical flue loss is only 2-3 %. This
creates greater demands on your chimney and on how to adapt the boiler to its existing installation. It is important, if you have
condensation to prevent it; otherwise you risk developing soot into the chimney and corrosion in the boiler.
Note: Even if there is water in the boiler, it may be due to condensation from the chimney.
Things that can prevent condensation in the boiler and chimney.
1. High chimney> 5m.
Provides a good draft in all conditions.
2. Small cleaning in the chimney 125mm – 150mm.
Provides better flow, and can ”carry” out more moisture.
3. Short un-insulated smoke pipe < 0,5m.
Do not cool down the smoke unnecessarily before it reaches the chimney.
4. High boiler temperature >70C degrees .
10 degrees up in the boiler temperature gives 10 degrees more smoke temperature.
5. Suitable return temperature > 55C degrees.
The boiler may condense when the heat exchanger surfaces are below 47 degrees.
6. Heated boiler room.
Lowers cooling of the boiler and smoke pipe and provides draft stabilizer more hot air to work with.
7. More oxygen in combustion.
Increases air flow in the boiler, and carries more moisture, 1 % more oxygen costs approx. 0,5 % in efficiency.
8. Remove the turbulators.
Decreases resistance of the boiler, and get a bad chimney to work better. The gas temperature typically increases to approx. 100 degrees.
The burner should be readjusted after the turbulators are removed.
9. Keep the boiler heated at all times.
If you are using DHW priority in the controller, and the boiler starts being cold by every start, the boiler will not manage to dry out at
every start.
10. Avoid limiting Max Power% under Weather Compensation
Limiting Max Power% under weather compensation should be performed only by a certified RTB professional that is familiar with the
specific operations of the system. Limiting the power% could have the effect of preventing your boiler from reaching the wanted
boiler temperature and thus could cause condensation in the boiler. Warning: damages resulting from condensation are not covered in
the manufacturer warranty.
PREVENTING FLUE GAS
CONDENSATION:
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