This apparatus is used for determination of cold filter plugging point (CFPP) temperature of diesel and domestic fuels including those containing flow- improving or other additives, intended for use in diesel engines and domestic heating installations. A specimen of the sample is cooled under specified conditions and, at intervals of 1OC, is drawn into a pipet under a controlled vacuum through a standardized wire mesh filter. The procedure is repeated until the amount of wax crystals that have separated out of solution is sufficient to stop or slow down the flow so that the time taken to fill the pipet exceeds 60 seconds or the fuel fails to return completely to the test jar before the fuel has cooled by a further 1OC.