Buying guide
6 mm or 8 mm pellets?
Your appliance manual specifies the right diameter. Do not choose by boiler output or assume that bigger is better.
Find the fuel specification
Check two things before buying
Note the exact model
Read the nameplate or boiler documents. Record the manufacturer, full name and version. If the burner has a separate manual, check its model too.
Visit the manufacturer’s website
Look under downloads for the manual for that model and version. Search the PDF for “fuel”, “pellet” or “diameter”. The brand name alone is not enough.
Two manuals, two different specifications
These examples apply only to the named models and manual editions. Do not apply them to the whole brand. Check the other fuel requirements too — diameter alone is not enough.
STALMARK
EKO SILVER III
6–8 mm
diameter ø6-8 mm
DTR ver. 8 · section 3 “Fuel” · page 12 (13 in the PDF)
Translated from the Polish manual.
DEFRO
Which pellets for a DEFRO boiler?
SMART EKOPELL
6 mm
pellet diameter Ø6mm
Edition XLII · December 2025 · section 5 · page 7
Translated from the Polish manual.
What does your manual say?
Expand the matching specification.
6 mm only
Choose 6 mm. Do not try 8 mm or change feeder or burner settings to accommodate an unsupported fuel.
6 mm and 8 mm
You can compare both diameters if they also meet the manual’s other requirements. Check the marking on the bag before buying.
No manual or unclear specification
Ask the manufacturer or authorised service for the manual and confirmation for your exact boiler and burner model. Do not guess from its output or advice about a different appliance.
Know the diameter? Compare offers
These filters select the diameter stated in the offer and exclude missing information. They do not confirm compatibility with your boiler. Gross PLN prices, delivery in Poland.
How many pellet bags are on a pallet?