The external equalizing line should be installed downstream of the thermostatic expansion valve at the ______.

The external equalizing line should be installed downstream of the thermostatic expansion valve at the ______.

• A. Diaphragm
• B. Receiver
• C. Compressor
• D. Condenser

Answer: (A)

External equalizer lines let the valve see the actual suction pressure at the evaporator outlet, so the expansion valve can regulate flow accurately despite pressure drops across the evaporator. That pressure must be fed into the diaphragm chamber of the valve—the part that modulates the needle against the spring—so the valve responds to the real load on the evaporator. If the equalizer were connected elsewhere, the valve would sense the wrong pressure and could overfeed or underfeed. Therefore, it’s placed downstream of the thermostatic expansion valve, connected at the diaphragm.

External equalizer lines let the valve see the actual suction pressure at the evaporator outlet, so the expansion valve can regulate flow accurately despite pressure drops across the evaporator. That pressure must be fed into the diaphragm chamber of the valve—the part that modulates the needle against the spring—so the valve responds to the real load on the evaporator. If the equalizer were connected elsewhere, the valve would sense the wrong pressure and could overfeed or underfeed. Therefore, it’s placed downstream of the thermostatic expansion valve, connected at the diaphragm.