Refrigeration & Air Conditioning USCG Question #249 (Set 5)

When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb?

Official USCG Answer & Rule Citation

Correct Answer: Option D — with steel wool or an abrasive cloth remove oxidation on the bulb and suction line

Removing oxidation with an abrasive cloth or steel wool ensures maximum metal-to-metal thermal conductivity between the suction line and the TXV sensing bulb, preventing inaccurate thermal response caused by corrosion or surface scale.

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