Question 191Refrigeration & AC - 1st Asst/Chief
70% to passWhen replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb?
Aapply a heavy coating of grease to function as a heat sink
Bwith steel wool or an abrasive cloth remove oxidation on the bulb and suction line
Capply a light film of oil to increase heat transfer
Dcarefully coat the device with silicone sealant to reduce the effects of convective cooling
AI Explanation
The correct answer is B) with steel wool or an abrasive cloth remove oxidation on the bulb and suction line. When replacing a thermostatic expansion valve power element, it is important to remove any oxidation or buildup on the thermal bulb and suction line. This ensures proper heat transfer and accurate temperature sensing, which is crucial for the proper operation of the expansion valve. Applying grease, oil, or sealant (options A, C, and D) can interfere with heat transfer and should be avoided. Properly cleaning the components as described in option B is the appropriate step to take when replacing the power element.
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