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Optimal Coal Oven Settings: Guide for 25KW Furnace, Feeding & Pause Tips, and Chimney Heat Issues

boczek29 35229 16
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Jak ustawić podawanie, przerwę i nadmuch w kotle 25 kW na ekogroszek, gdy komin jest gorący, a paliwo nie spala się prawidłowo?

Zmniejsz nadmuch do około 40% i skróć czas podawania do 8 sekund, a potem obserwuj pracę kotła i koryguj małymi krokami: jeśli nadal wyrzuca węgiel, skracaj podawanie o 1 sekundę, a jeśli kopczyk się zapada, wydłuż je [#17538465] Przy zmniejszaniu nadmuchu trzeba jednocześnie zmniejszyć dawkę paliwa albo wydłużyć przerwę, bo inaczej palenisko będzie się dusić [#17538465] 70% nadmuchu przy takim przewymiarowanym kotle jest najpewniej za duże i może powodować „przelatywanie” opału w komin [#17538465] Sprawdź też ciąg kominowy, bo gorący komin może oznaczać zbyt duży ciąg, który przy zatrzymanym wentylatorze zasysa powietrze przez dmuchawę; pomaga regulator ciągu kominowego oraz klapka zwrotna na wentylatorze [#17536962][#17537660] Warto również sprawdzić szczelność pokrywy zasobnika, bo zasysanie powietrza przez zbiornik może cofać ciepło do podajnika [#17536962]
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  • #1 17536809
    boczek29
    Level 6  
    Posts: 5
    Rate: 11
    I have a problem with setting the stove for coal, I read various forums and I don't know how to set the driver myself.
    25KW furnace anyone can give their settings (feeding, pause during work)
    I am aware that if someone gives me their settings, it will not solve my problem, but I will have a reference point.
    Generally, the stove doesn't burn coal for me, the chimney is hot
    Please help
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  • #2 17536962
    Anonymous
    Anonymous  
  • #3 17536993
    kriso221
    Level 12  
    Posts: 28
    Help: 1
    Rate: 10
    I have an oven without a feeder but I suspect that the principle is similar. I set it up by trial and error until I thought it was ok for me.
    Pauze I have set for 8 minutes blow-in for 60 seconds.
    Blower fan from 20% to 40%
    Stopping the windmill as the furnace temperature drops to 33 degrees (always burns me)
    I also noticed that a lot depends on coal (I took it once from another supplier and I didn't burn it)
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  • #4 17537269
    sp3ots
    Level 38  
    Posts: 3065
    Help: 523
    Rate: 672
    kriso221 wrote:


    Windmill from 20% to 40%
    Stopping the windmill as the furnace temperature drops to 33 degrees (always burns me)


    The windmills are standing in the fields.
  • #5 17537371
    kriso221
    Level 12  
    Posts: 28
    Help: 1
    Rate: 10
    Sorry, I meant: a blower fan.
  • #6 17537644
    boczek29
    Level 6  
    Posts: 5
    Rate: 11
    Well, the fact is that I have actually given little information.
    Namely
    By settings
    Passing 13 seconds
    Pause 58 seconds
    Fan 70 percent flap on the fan half open it can be said that it burns out but the chimney is hot so I tried to reduce the speed then ejects coal and slakes
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  • #7 17537660
    korystor
    Level 19  
    Posts: 372
    Help: 35
    Rate: 102
    Install the chimney draft regulator. In addition, you should have a non-return flap mounted on the fan, it opens itself when blowing. Your settings are not much different from the examples.
  • #8 17537689
    internick
    Level 36  
    Posts: 3081
    Help: 273
    Rate: 552
    And what is this cauldron? How many meters do you heat? What driver? What peas?
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  • #9 17537891
    boczek29
    Level 6  
    Posts: 5
    Rate: 11
    meters for heating 150m2
    when it comes to fuel, I only know calorific value 27
    TECHNIX ARGOS PID controller
    RMS fan - 120 AL MAX
    25kw boiler with a screw feeder
  • #10 17537939
    internick
    Level 36  
    Posts: 3081
    Help: 273
    Rate: 552
    What exactly is the boiler?

    What is the demand according to: http://cieplowlasciwie.pl/

    Insert the photo of the ash drawer and burner.
  • #11 17538045
    boczek29
    Level 6  
    Posts: 5
    Rate: 11
    Optimal Coal Oven Settings: Guide for 25KW Furnace, Feeding & Pause Tips, and Chimney Heat Issues20181104_1..829.jpg (1.11 MB)You must be logged in to download this attachment.
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  • #12 17538089
    internick
    Level 36  
    Posts: 3081
    Help: 273
    Rate: 552
    The fact that the chimney is hot is better than tar is supposed to flow in it as a by-product of low exhaust gas temperature.

    On the right side of the crown and on the front like a cauliflower. Is the blow good there? Is everything tight? When was the boiler and chimney cleaned?

    How much was the demand for heat according to the page I gave?
  • #13 17538141
    boczek29
    Level 6  
    Posts: 5
    Rate: 11
    The following calculations assume that the average daily temperature of 23.0 ° C will be kept at home throughout the winter.

    15.5kW - maximum heating power
    That much will be needed on the "coldest" day, with a daily average of -20 ° C.
    This means that for each hour of the day in the building you need to "pump" an average of at least 15.5kWh so that the temperature does not drop inside.

    7.3kW - average heating power
    That much will be needed on an average winter day, with a daily average of 2.7 ° C.


    154W / m2 power demand indicator
    This value can be found in the table of approximate boiler power selection from its manufacturer.

    36 327kWh = 131GJ total annual energy consumption for heating
    So much net heat your home needs for the entire heating season. Depending on what and with what efficiency you will heat, the amount of gross heat you need to buy in fuel will be correspondingly higher.

    360kWh / m2 * year energy consumption indicator


    the boiler and chimney are cleaned on a regular basis, rather all airtight smoke is not released outside
    when it comes to blowing, I think I don't know how to check it
  • #14 17538218
    internick
    Level 36  
    Posts: 3081
    Help: 273
    Rate: 552
    Now you see how much you have an oversized boiler?

    What tank do you have and at the current temperature is it enough for you? Or otherwise - 25 kg of peas is enough for .... days?

    And what happens if you switch to automatic mode and the controller will choose the parameters based on the boiler temperature setpoint?
  • #15 17538347
    Anonymous
    Anonymous  
  • Helpful post
    #16 17538465
    hajtaler
    Level 21  
    Posts: 346
    Help: 52
    Rate: 78
    Buddy 70% turnover is definitely too much in addition with such an oversized boiler - you are packing cash into clouds. I suspect you don't have an exhaust gas temperature sensor?
    When reducing the blower speed it is normal that if you do not simultaneously reduce the carburizing of the burner (reducing the feeding time or increasing the pause) then you will have a low
    I suggest you reduce the blowing power to 40% and feed time to 8 seconds. Watch for a few hours. If it continues to flip but keep cutting time shorter but slowly (by 1 sec and watch). If the mound collapses, the opposite is true - extend the feeding time.
  • #17 18731995
    Bałdyzer
    Level 12  
    Posts: 1396
    Rate: 225
    Not wanting to create a new topic, I would like to ask you about one thing. Is it possible to smoke eco-pea coal in a regular old Ogniwo 17KW furnace? Currently, prices of pea coal in bags are at a really low level, I would like to be more ecological and smoke from above with pea coal and dry beech.

Topic summary

✨ The discussion revolves around optimizing settings for a 25KW coal furnace, specifically addressing issues with coal burning efficiency and chimney heat. Users share their experiences and suggest settings for feeding time, pause duration, and blower fan speed. Common recommendations include installing a chimney draft regulator and a non-return flap on the fan to manage air supply. The importance of coal quality and proper maintenance of the boiler and chimney is emphasized. Users also discuss the impact of boiler size on efficiency and suggest adjustments to feeding and blower settings to improve performance.
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FAQ

TL;DR: Start around 40% fan and 8 s feed; "70% turnover is definitely too much." Then fine‑tune pause and draft to stop a hot chimney. This FAQ helps 25 kW coal‑boiler owners fix poor burn and reduce fuel waste. [Elektroda, hajtaler, post #17538465]

Why it matters: Clear starting points and draft fixes solve hot‑chimney, overfeeding, and slaking issues fast for feeder coal boilers.

Quick Facts

What are good starting feed, pause, and fan settings for a 25 kW screw‑feeder boiler?

Drop the blower to about 40% and set feed near 8 seconds. “70% turnover is definitely too much.” Observe the fuel mound. If it flips forward, shorten feed by 1 second and recheck. If the mound collapses, lengthen feed slightly. Keep your current pause initially, then tune it last. This stabilizes combustion and cuts waste. [Elektroda, hajtaler, post #17538465]

Why is my chimney hot, and how do I fix overdraft?

Excessive chimney draft can pull air through the fan even when it’s stopped, overheating the flue. Fit a flap that closes the fan inlet when off. Check the coal hopper lid and seals for leaks. Air entering via the reservoir can cause heat return through the feeder. Reduce uncontrolled air, then re‑tune feed and fan. [Elektroda, Anonymous, post #17536962]

Why does lowering fan speed make the fire go out or push coal out?

When you cut air, you must also cut fuel. Reduce feed time together with blower speed. If you only lower air, the bed cools and slakes. If you only lower feed, the mound may collapse. Tune in small steps and observe the bed shape and flame. [Elektroda, hajtaler, post #17538465]

Are 13 s feed, 58 s pause, and 70% fan reasonable?

The fan is too high. Lower it to about 40% and re‑check combustion. Shorten feed by small steps if the mound flips; lengthen if it sinks. Keep your existing pause until air and feed stabilize. Then trim pause to stop unburned push‑out. [Elektroda, hajtaler, post #17538465]

Do I need a chimney draft regulator or a non‑return flap?

Yes. Install a chimney draft regulator to tame excessive draft. Use a non‑return flap on the fan so the inlet closes when the blower stops. These two items stabilize air supply and protect the feeder. [Elektroda, korystor, post #17537660]

How much does fuel quality affect burn stability?

A lot. Different coal batches behave differently. Poor batches may not ignite cleanly or sustain a stable mound, even with good settings. If switching suppliers changes results, re‑tune air and feed, or change fuel. [Elektroda, kriso221, post #17536993]

What info should I share to get useful tuning help?

Provide boiler make and model, heated area in m², controller type, fuel type/class, and current settings. Photos of the burner and ash drawer help diagnose air distribution and burn quality. Include recent cleaning status. [Elektroda, internick, post #17537689]

Is my 25 kW boiler oversized if my home’s max demand is 15.5 kW?

Yes, it’s significantly oversized. Your calc shows 15.5 kW peak and 7.3 kW average. Oversizing causes cycling, hot flue, and poor efficiency. Mitigate by reducing air, shortening feed, and stabilizing the fire bed to match actual load. [Elektroda, boczek29, post #17538141]

Is a hot chimney always bad?

Not necessarily. A warm flue can be better than a very cold one that tars up. Very low exhaust temperatures promote condensate and tar. Balance by controlling draft and air while keeping clean combustion. [Elektroda, internick, post #17538089]

How do I manually tune a feeder boiler fast? (3‑step)

  1. Set blower ≈40% and keep your current pause.
  2. Set feed ≈8 s, then adjust by 1 s watching the mound.
  3. When the mound stays stable and ash is gray, trim pause to prevent unburned push‑out. [Elektroda, hajtaler, post #17538465]

How can I check airflow and sealing on the burner?

Inspect the burner crown and front for ash build‑up that looks like cauliflower. Ensure passages are open and seals intact. Confirm the boiler and chimney are recently cleaned. Uneven deposits and leaks indicate poor air distribution or overdraft. [Elektroda, internick, post #17538089]

Should I try automatic PID mode on my controller?

Yes. Switch to automatic mode and let the controller choose parameters to hit your setpoint. Observe behavior and ash quality. If results improve, keep auto; if not, return to manual and tune as above. [Elektroda, internick, post #17538218]

What fuel consumption signals overfeeding?

An example calculation showed roughly one scoop per minute, about six buckets per hour, equating to about 120 kWh/h of fuel energy. That rate is excessive for typical residential loads and indicates overfeeding and overdraft. Reduce air and feed, then reassess. [Elektroda, Anonymous, post #17538347]

Can I burn eco‑pea coal in an old 17 kW Ogniwo without a feeder, top‑down with wood?

Only if the boiler’s manual explicitly allows that fuel and method. Follow the manual’s fuel list and setup guidance. If it doesn’t approve pea coal or top‑down lighting, do not do it. “The boiler manual provides optimal presets and correction methods.” [Elektroda, Anonymous, post #17536962]

How do I prevent heat returning through the feeder?

Seal the hopper lid and check its gasket. Fit a flap that closes the fan inlet when the blower stops. Excess draft can pull air through the fan or reservoir and route heat back into the feeder. Fix leaks, then re‑tune. [Elektroda, Anonymous, post #17536962]
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