dual evaporator system work properly is called a cross charge valve. A cross charged valve has a refrigerant in the power element that is different than what the system is operating with. These were also designed for use in rear, auxiliary or dual evaporator systems to reduce harmonic synchronization sometimes called "hunting". See Figure 3. It is important to know that there are flow prevention devices that will isolate refrigerant flow for Dianetti/Milliman valve or "nicked seat" valve or "bleed" valve. These are a special valve made to have a small amount of controlled leakage through the seat of the valve, even when it is closed or not in use. This can be done in either block valve or right angle valve. Using one of these is recommended for relatively long and low mounted return lines from rear evaporators (Figure 2). Another type of specialty valve used to make a Figure 3: The cross charge valve can be an effective way to prevent TXVs used on dual evaporator systems from fighting for control of the refrigerant flow. October 2020 3 MACS Service Reports