Which of the tools listed must be used when retightening the plate type heat exchangers used in the device shown in the illustration? Illustration MO-0110

Correct Answer: Option A — Steel ruler or tape measure

Plate heat exchangers are compressed to a specific design dimension to ensure proper gasket sealing without damaging the plates. A steel ruler or tape measure is the required tool to verify the plate pack compression length, as specified by the manufacturer's maintenance manual for the specific unit model.