A solenoid valve with a built-in check valve is designed to replace a liquid line solenoid valve in parallel with a check valve for reverse flow. This valve may be applied in the liquid line of a supermarket case for positive shutoff during pump down control, while allowing full flow in the reverse direction during reverse gas defrost. It may also be used in the liquid line of a heat pump to prevent migration of refrigerant to the outdoor unit during the heating mode, while allowing full flow in the reverse direction during the cooling mode.
CAUTION: This valve will not close in the reverse flow/cooling mode.
CE6-HP SERIES SOLENOID VALVES
See Figure 1. The check ball is small and inserted into the pilot port of the disc. When the valve is energized for operation in the refrigeration flow direction, the pressure on top of the disc is bled off through the pilot port and the disc raises. When the evaporator goes into defrost or the heat pump switches to the cooling mode, the solenoid valve must be energized. The reverse flow causes the check ball to close the pilot port from the bottom, pushing the disc up, fully opening the valve.
CE6S1-HP* BI-DIRECTIONAL SOLENOID VALVE*
The “C” is used in this nomenclature to represent the check valve feature and the“-HP” designates high pressure.
The check valve disc also requires a modification in the stem and plunger assembly. Therefore, the disc and stem and plunger assembly must be changed to convert a standard solenoid valve to one with a built-in check valve. Internal parts kits are available for solenoid valves with the built-in check valve.
CE6S1-HP BI-DIRECTIONAL SOLENOID
HEATING MODE (shown above)
Typically, the valve is installed with normal flow to the outdoor coil. When de-energized, this prevents migration of refrigerant to the outdoor coil during heating mode.
Typically the valve is installed with normal flow to the outdoor coil. When in cooling mode, the valve is in reverse flow.
See Figure 3 below. For reverse gas defrost, a liquid line solenoid valve can be installed with a check valve in parallel, to allow reverse flow to the liquid header. This adds the expense of labor and materials. Or, a Sporlan liquid line solenoid valve with the built-in check valve feature can be installed, saving time and money.
Article contributed by Dustin Searcy, Product Manager, Electric and Solenoid Valves, Sporlan Division, Parker Hannifin
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