PHA Heating Pellets are made from recycled timber shavings sourced from a number of timber mills in NSW. Unfortunately, we do not always know the specific species of timber we are receiving, as there can be up to 10 different species in a load of timber shavings. Additionally, these different timbers may also affect the colour of our heating pellets too.

Occasionally problems can arise with this raw material and consumers may get a “glass-like” residue or chunks of hard ash in the burn-pot of their pellet heater. These are known as “CLINKERS”!

Clinkers can be caused in a number of ways:

  • If the trees that have been used by the timber mills were grown in sandy conditions the sand can be sucked up into the trees, and is processed as a part of the tree. As a consequence, there can be some sand in the heating pellet, and when these pellets are burnt at high temperatures they form glass-like clinkers. If they occur, they need to be removed from the burn-pot (in your pellet heater) every day. Sometimes they may have to be scraped out with a screw driver.
  • The other form of clinkers, may look like pumice, grey-white or blackish chunks. These may be formed because “wood, being a natural product, may contain impurities. When wood is pelletised for use in pellet-burning stoves, those impurities can result in “clinkers” being formed. A clinker is a particle that isn’t burned during the normal combustion process in your heater. It looks like a chunk of hard ash but can break down easily. Clinkers may also form when minerals in the ash fuse together.”

As there is no way of being able to ascertain whether there are any problems with our raw timber shavings we never know when clinkers may arise.

PHA does continuous quality testing of our heating pellets. We use a pellet heater for this testing, and from time to time we do notice some of these clinkers can form. We have not had this particular problem for several years. Our instructions to overcome this issue with your pellet heater is that it is absolutely necessary to clean the heating chamber out every day during the winter season. This is so there is no build up of ash, which can cause the problem. It is also important for successful burning of heating pellets to make sure that there is no ash under the burn-pot liner which is where ash can build up and stop the air flow.