🔍 Key Concepts

• TXV (thermostatic expansion valve) bulb must sense true suction gas temperature for correct superheat control • Oil and any liquid refrigerant in a horizontal suction line tend to collect at the lowest point of the pipe • On larger suction lines (7/8" and up), the bulb should be placed on the side quadrant of the pipe, not exactly on the top or very bottom

💭 Think About

• On a horizontal suction line, what happens to oil and any remaining liquid refrigerant inside the pipe, and how would that affect a bulb mounted exactly at the bottom? • If the bulb is mounted exactly on top of the line, will it be in the best contact with the flowing refrigerant, or can stratification and warm ambient air around the pipe affect its reading? • Looking at positions A–D, which one places the bulb in a side‑lower quadrant (about the 4 or 8 o’clock position) so it senses gas temperature well but avoids the oil/lquid at the very bottom?

✅ Before You Answer

• Make sure the bulb is not at 6 o’clock (very bottom) where it could be affected by pooled oil or liquid refrigerant • Make sure the bulb is not at 12 o’clock (very top) where it may sense warmer pipe/ambient effects instead of the main gas stream • Confirm that the chosen option shows the bulb in a side-lower quadrant (about 4 or 8 o’clock) with firm contact and strapping on the large suction line