Question 133Refrigeration & AC - QMED
70% to passWhen opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted with packed valves, what must you do?
Ayou must first remove the stem seal cap
Byou should replace the gasket each time the valve position is changed
Cyou should never loosen or tighten the packing gland
Dyou should turn valves slowly to avoid thermal stresses due to low temperatures
AI Explanation
The correct answer is A) you must first remove the stem seal cap. When opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted with packed valves, you must first remove the stem seal cap to access the packing gland. This allows you to properly tighten or loosen the packing gland to control the valve's seal and prevent leaks, without risking damage to the packing. The other answer choices are incorrect because: B) replacing the gasket each time is unnecessary, C) you should adjust the packing gland as needed, and D) turning the valves slowly is a good practice, but not the primary requirement.
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