Cleaning & Care

Cleaning and Maintenance of the Oven Fine Dust Filter

Fundamentals of Filter Cleaning

Regular cleaning of your stove’s fine dust filter is crucial for its longevity and optimal filter performance. A well-maintained system not only reliably reduces emissions, but also ensures the safe operation of your fireplace. The cleaning intervals depend largely on your individual heating behaviour and the quality of the fuel used.

The filter works with two different cleaning mechanisms: the catalytic converter unit reduces toxic carbon monoxide by oxidising it into non-toxic carbon dioxide, while the particulate filter unit mechanically filters particles out of the exhaust gas. Both components require different cleaning approaches and intervals.

Important Cleaning Principles:

  • Regular visual inspections
  • Documentation of all cleaning work
  • Use of appropriate protective equipment
  • Observing the recommended cleaning intervals
  • Timely replacement of wear parts

Cleaning Intervals According to Intensity of Use

The frequency of cleaning required depends on your individual usage. As a rule of thumb, the more intensively you heat, the more frequently the filter needs to be serviced.

Recommended cleaning intervals are:

Occasional use (2-5 hours/week)

  • Weekend users or occasional heaters
  • Fine dust filter: at least once a month
  • Catalytic converter: every 2-3 months
  • Bypass check: weekly

Regular use (5-10 hours/week)

  • Heating on particularly cold days
  • Fine dust filter: at least once every 14 days
  • Catalyst: monthly
  • Bypass check: before each use

Intensive use (10-20 hours/week)

  • Primary heating source during the cold season
  • Fine dust filter: at least once a week
  • Catalyst: every 2-3 weeks
  • Bypass check: daily

These intervals are guidelines that you should adapt to your specific situation. At the beginning of the heating season, we recommend a weekly visual inspection to familiarise yourself with the individual contamination behaviour of your system.

Cleaning the Fine Dust Filter Unit

The Open-Flame Process

The fine dust filter unit uses high-temperature-stable glass fibres that effectively bind soot particles. These deposits can be removed using a special burn-off process that enables the filter to be regenerated. The burn-off process thermally decomposes the dust particles that have agglomerated into coarse dust.

 

Step-by-step instructions for burning:

  • Put on fireproof gloves
  • Provide a base for the dirty filter
  • Plan cleaning during the embers phase of the last burn

  • Loosen the clamp holding the inspection flap
  • Carefully remove the fine dust filter
  • Place the filter on a prepared surface

  • Close the inspection flap again
  • Open the firebox door
  • Place the filter horizontally in the glutaraldehyde atmosphere (NOT in open flames!)

  • Leave the filter in the embers overnight
  • Wait until it has cooled completely
  • Remove the next morning

  • Insert cooled, clean-burnt filter
  • Align bypass side with inspection opening
  • Close flap securely

Important Information About Filter Material

The filter material must never be touched directly or cleaned mechanically. Burning off the accumulated particles thermally decomposes them without damaging the filter structure. However, after numerous regeneration cycles, the filter performance may decline.

Replacement criteria for the filter unit:

  • Renew at least once a year
  • Replace immediately if visible damage is detected.
  • If filter performance declines despite cleaning
  • After blockage by tar or resin

Cleaning the Catalytic Converter Unit

Catalytic converters require a different cleaning method than particulate filters. The primary aim here is to remove dust deposits from the catalytically active surface without damaging the precious metal coating.

Cleaning Procedure for the Catalytic Converter

Requirements:

  • Fireplace completely cooled down
  • Flue gas pipe at room temperature
  • Disposable gloves to protect the coating
  • Vacuum cleaner with brush nozzle or ash vacuum cleaner

Cleaning is carried out exclusively mechanically by carefully vacuuming or brushing the surfaces:

  • Open the service flap and remove the fine dust filter.
  • Remove the catalytic converter bracket with both catalytic converters
  • Clean in a suitable place (ideally outdoors)
  • Remove deposits with a vacuum cleaner and soft brush.
  • Do not use cleaning agents or water!
  • Reinsert the cleaned catalytic converter unit (note the positioning aids).
  • Insert the fine dust filter and close the flap.

Condition Check of the Catalytic Converter

Each time you clean the catalytic converter, you should check it for the following characteristics:

Signs that replacement is necessary:

  • Spalling coating
  • Visible cracks in the ceramic structure
  • Permanent discolouration due to overheating
  • Blockage caused by tar (cannot be cleaned)

Bypass cleaning and safety inspection

The bypass is the most important safety feature of your filter system. Regular cleaning, inspection and maintenance are of the utmost importance.

Visual Inspections

You should check the following points at regular intervals through the service flap:

Control Checklist:

  • Bypass opening free of deposits
  • No visible blockage of the filter unit
  • Catalytic converter cells throughout
  • Service flap seal intact
  • No soot marks at joints

Fuel and Operating Mode

The type of fuel and how you operate your stove have a significant impact on maintenance requirements. Using high-quality, dry logs significantly extends maintenance intervals.

Optimal Fuels

Suitable types of wood:

  • Beech (ideal due to high calorific value)
  • Ash (good embers)
  • Birch (clean combustion)

Fuels to avoid:

  • Resinous conifers (spruce, pine, as the exhaust gases clog the filter system more quickly due to the resins)
  • Treated or varnished wood
  • Chipboard or plywood
  • Damp wood (over 20% residual moisture)
  • Oak (greater risk of soot formation at low temperatures)

The use of unsuitable fuels leads to increased soot and tar formation, which can quickly block the filter. Tar deposits cannot be cleaned and require complete replacement of the affected components.

Operating Tips for Minimising Maintenance

Optimal heating behaviour allows you to extend maintenance intervals and increase the service life of your filter:

Optimise the heating phase:

  • Use thinner kindling
  • Ensure adequate air supply
  • Avoid ‘simmering’ with reduced air supply

Prefer full load operation:

  • Better short and hot than long and smouldering
  • Catalytic converter operates more efficiently at higher temperatures
  • Less soot and tar formation

Take advantage of regular periods of intense activity

  • Ideal for filter regeneration
  • Burns deposits in the system
  • Keeps the chimney clean

Fault Correction

Despite regular cleaning and maintenance, problems can occasionally arise. Early detection and rectification prevents major damage and downtime.

Problems and Solutions

Problem: Poor chimney draught when heating up

Possible causes and remedies:

  • Catalytic converter with significant dust accumulation on the inlet side → Perform cleaning
  • Filter overloaded → Burn off or replace
  • Chimney dirty → Contact chimney sweep

Problem: Smoke odour in the installation room

Immediate measures:

  • Interrupt combustion
  • Ventilate the room thoroughly
  • After cooling down, check all seals.
  • Check connection points
  • Replace seals if necessary

Annual maintenance checklist:

  • Complete dismantling and cleaning of all components
  • Condition check of catalytic converter and filter
  • Check all seals
  • Checking the clamp connections
  • Visual inspection of the pipe system
  • Replacement of the fine dust filter unit
  • Documentation of the maintenance date

Maintenance Documentation

Keep a maintenance logbook in which you document all work carried out:

Information to be documented:

  • Date of maintenance
  • Work carried out
  • Condition of components
  • Replaced parts
  • Special occurrences
  • Next scheduled maintenance date

This documentation will help you to identify wear patterns and optimise maintenance intervals.

Professional cleaning and maintenance

While many maintenance tasks can be carried out yourself, there are situations where professional help is advisable:

When you should consult a professional:

  • In the event of unexplained performance losses
  • After overheating damage
  • In the event of structural damage to the filter
  • For the annual main inspection
  • If you are unsure about the condition of the components

Final care instructions

Regular maintenance of your BERTRAMS furnace dust filter is a worthwhile investment. A well-maintained system not only works more efficiently and safely, but also has a significantly longer service life. With the right care, you can minimise your environmental impact while keeping operating costs low.

Remember: preventive maintenance is always cheaper than repairing damage. Take the time to carry out regular checks and cleaning – your health and the environment will thank you for it.

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