Coffee Roaster Airflow Issues on a Probat L12

Commercial shop roasters require a lot of cleaning and care: This week at Sweet Maria’s, we performed a deep clean to address airflow issues on our Probat L12.

We were experiencing issues with the flame going out when switching from the cooling tray fan back to the drum. This triggered us to perform quarterly maintenance.

First step was to remove the jets and clean them:

Dirty jets removed from machine.
The heads were removed by unscrewing them from the base, and then soaking in a sodium carbonate solution overnight. We used a wire brush and scouring pads the next day to take off any potential carbon build up.

Repositioning the starter:

We identified that the starter was out of place, causing issues with igniting the flame at initial start up.

Next we removed the tray and cleaned all chaff and creosote build up from the chaff collector:

Probat L12 cooling tray removed.
Removed the cooling tray to reveal a build up of chaff that was hindering air flow.

Be sure to clean the space between the cooling tray and chaff collector. We use a bottle brush to clean this space which you can access from above when the cooling tray is off, and below from the chaff collector. We predict this was the largest factor affecting our airflow.

Cleaned on either side of the chaff hatch doors where chaff, chips and creosote tend to build up.

End result – The flame started up right away!

Flame after cleaning.
Clean jets installed with starter in place.

Other info about Commercial Roasters:
Probat L12 Replacement Belts
Cleaning Out the Squirrel Cage of a Probat L12
How to Move a Commercial Coffee Roaster

2 Responses

  1. Thanks for the informative post!! This is excellent! Did you remove the heat shield from the burner? If so, how did you modify your roasting? Thanks!!

  2. There is a burner deflection shield installed around the drum. The flame will hit this first to distribute heat evenly to the drum. This should always be in place.
    The side shield with the Probat logo on it is in place to keep you, the roaster, comfortable. We removed this shield to access the burners, as seen in the photographs, but always roast with them in place.

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