It has been common to build pellet stores in existing rooms or cellars, often designed and constructed by the property owner.  The advantages of a custom built pellet store are good space utilization and – in the case of storage room with exterior walls – easy access to the filling and vacuum nozzles. However, inadequate self-constructed stores cause considerable problems and risks.

Custom built stores should generally be planned, built and equipped by qualified professionals, and in line with ENplus guidelines.

Prefabricated storage systems offer a well-planned solution including the appropriate filling and extraction devices that ensure that pellet quality is maintained and operation is safe.  For this reason we recommend the use of prefabricated pellet storage systems.  These are a good example

The full version of ENplus storage guidelines can be downloaded here, and we recommend you read them in full when planning. However here is a brief summary:

  1. Pellet stores should accommodate one year’s pellet consumption for small domestic users (we recommend minimum of 5 tonnes)

  1. -Real storage capacity is always smaller than theoretical total room volume. Volume is lost beneath raised or sloping floors.  Pellets will not fill above the bottom edge of the filling nozzles, and they will slope down from a peak in line with the filling nozzle

  1. You should be able to access the store easily to remove pellets or carry out any maintenance work

  1. There should be viewing windows that clearly show the pellet levels in the store

  1. The store should be located somewhere accessible by a lorry

  1. -A road width of at least 3.5m and without height limits that may impede access (e.g. low hanging cables or branches)

  1. -Store should ideally be within 12 metres of where the lorry will park

  1. -The lorry must be able to park legally and without creating an unacceptable obstruction for the duration of the delivery (which may take over an hour)

  1. Filling couplings should be at a maximum height of 1.8m and should be of type “Storz A”

  1. Blowing and exhaust couplings must be properly labelled

  1. Stores should be cleaned out a minimum of every two years, or every 5 deliveries

Fines – Small Troublemakers

  1. Fines refer to fragments of broken pellets that fall through a sieve with holes of 3.15mm diameter, or dust. A high amount of fines may cause problems with the boiler or pellet retrieval system.

  1. Fines in the pellet store are caused mainly by mechanical stress during pellet delivery. Bends in the pipework, inadequate impact mats, obstacles in the route of the pellets, all increase the amount of fines.  High fines at the boiler may also be due to damage from the extract system taking pellets from the store to the boiler. Through particle segregation processes in the store, fines will concentrate over time on the bottom of the pellet store.

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  1. Particle segregation will occur during delivery and the results can also be seen typically with the ‘face’ of a slope of pellets appearing dusty – the appearance of a dusty ‘face’ DOES NOT mean the pellets are outside the ENplus specification

  1. Puffin will only accept a complaint of fines based on the following criteria:

  2. The amount of fines in the store is more than 4%

  1. The distance that the pellets travelled from delivery lorry to store is less than 20 meters

  1. The store complies with ENplus guidelines (inc frequency of cleaning)

  1. There was less than 10% of pellets in the store prior to delivery

  1. Maximum of 20% of the new delivery has been used