How to Know When a Heat Exchanger Is Bad

A heat exchanger is a device for transferring heat from one substance to another substance. Heat exchangers can be found in your daily life as the radiator in your home or car, the coils on your refrigerator and on the CPU of your computer. Heat exchangers can go bad for two main reasons: the coils becoming cracked and leak or the passage in which the the substances flow through becomes fouled, decreasing the flow and reducing the heat transfer rate. A leak is generally quite obvious, while excessive fouling is often harder to detect.

Heat exchanger
2 Pressure gauges

Instructions

- 1
  Disconnect the heat exchanger from its normal source and drain it.
- 2
  Connect a pressure gauge at each end of the heat exchanger, then reconnect the source and drain.
- 3
  Turn on the source and read the difference in pressure between the input and the output. Heat exchangers will be rated at a particular pressure drop (called head loss) depending on the particular internal shape. Pressure drops of 50 percent greater than the rated drop indicate a fouling of about 25 percent of the inside tubes. Anything over 25 percent fouling and performance of the heat exchanger is going to too low to be of any practical use, and the heat exchanger should be cleaned or replaced.

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