Abstract: An apparatus and a process for testing fluid from a heat exchanger. A first fluid from a heat exchanger to be tested is passed through a test heat exchanger. A second fluid is circulated through the test heat exchanger with a pump. The second fluid is heated with a heater so that a temperature in the test heat exchanger can be controlled, for example, to so that conditions in the heat exchanger are close to the conditions in the heat exchanger. After a period of time, the test heat exchanger can be removed and inspected, tested, or both. Also, multiple test heat exchangers may be used to test various process conditions. Additionally, the test heat exchangers may include different materials to test various materials.