Attach the desired test piece to the constant temperature bath.
Attach the cooling water chamber to the other end of the test piece. [The test piece is already insulated so that there is no heat loss from it in radial direction]. Charge the given thermic fluid through the charging hole by using pipette. Do not charge the thermic fluid to full contents of the constant temperature bath. Keep some gap for expansion of thermic fluid on heating.

Start heating of thermic fluid by switching on the heater at the bottom of constant temperature bath. Initially supply full voltage to the heater in order to raise the temperature of thermic fluid at a faster rate. Eventually as temperature approaches the desired temperature, regulate the voltage to the heater in such a way that temperature is held constant in the constant temperature bath.

In the mean time, start cooling water supply to constant level over head tank and regulate its flow rate in such a way that condition of overflow is just maintained. Open the inlet valve of cooling chamber on the test piece and regulate the flow rate of water though cooling chamber. Measure the flow rate of cooling water by collecting it from the outlet line and adjust its flow rate to about 300 to 400 cc/min. depending upon the test piece. Ensure that temperature rise of cooling water is at least 2.5 - 3o C, when steady state conditions are attained.

Allow at least half an hour for steady state conditions to be attained.[Steady state condition is indicated by constant temperatures in the hot oil bath and constant temperature difference in the inlet and outlet temperatures of cooling water.]

Note down the hot oil bath and cooling water inlet & outlet temperatures. Also note down the flow rate of cooling water by collecting it in a measuring cylinder over a known period of time.

Repeat 4 & 5 for different hot oil bath temperatures.