Fig 1 shows ‘What is supposed to happen’ with the darker oil settling above the condensate (green) before flowing over the weir into the oil container leaving fairly clean condensate to pass from the bottom of the settling tank onto the pre-filter (yellow), through the carbon filter (grey) and out of the machine.

When working properly, the oil container will contain neat, liquid oil with no contaminants.

The oil quantity removed should equate to the amount used to ‘top up’ the compressors over a similar period of time.

Fig 2 shows no oil passing over the weir as most modern oils form thick emulsions that will not flow over a weir and so ‘build up’ inside the machine. Initially, the machine seems to be working well, with
fairly clear solution being produced but the primary separation device, the weir, is doing no work and leaving the carbon to remove all of the oil.

Fig 3 shows that the emulsion has filled the settling tank and reached the transfer pipe. As more condensate is introduced, emulsion must pass into the carbon chamber, quickly blocking the carbon and causing the machine to overflow.

Any oil that may be in the oil container will be washed out by the lighter emulsion that now passes over the weir due to the increased surface height inside the tank due to the blockage. A change of carbon elements will simply defer the problem for a few more days and the whole machine will need to be drained and pressure washed to allow the whole process to restart.