Solderable Bronze Freon Solenoid Valve — NC, Direct Acting, 1/4" and 1/2" Solder Connection

Cematic's solderable bronze freon solenoid valve is a normally closed, direct-acting solenoid valve for refrigerant control with a solder connection to copper piping.

Unlike the flare connection version, this model is installed by direct soldering into the refrigerant line, making it the standard choice in new installations where the technician solders on-site without the need for adapters or fittings.

Its normally closed configuration keeps refrigerant flow blocked when the coil is de-energized. It only opens when it receives an electrical signal. Consequently, in the event of any electrical failure, the flow is automatically cut off — the standard safety state in refrigeration circuits.

Operating Principle — Solderable NC Freon Solenoid Valve

Without power, the solderable freon solenoid valve remains closed, as the spring holds the plunger on the seat. When the coil is energized, the electromagnetic field directly displaces the plunger and opens the refrigerant flow. Conversely, when de-energized, the spring automatically returns the plunger to the closed position.

Its direct action operates from zero pressure, so it does not require a minimum differential pressure to function. This makes it suitable for systems that start without pressure or during defrost cycles where pressure temporarily drops.

Solderable vs. Flare Connection — Which to Choose?

The choice between solderable and flare connections depends on the type of installation. The solderable connection is correct in the following cases:

• New installations: Copper soldering is the standard method in new construction, thus avoiding the addition of mechanical joints that could be leak points.
• High-pressure systems: The soldered joint is more resistant to high pressures than the flare connection, as it does not rely on the mechanical tightening of the fitting to maintain the seal.
• Permanent installations: When the valve will not be disassembled for years, the solderable connection is more reliable in the long term and, additionally, eliminates the risk of leaks due to loosening of the flare nut.

The flare connection, on the other hand, is correct when the valve needs to be disassembled for maintenance without cutting the piping. For that application, see the freon solenoid valve with flare connection →

Construction Materials

The body is made of high-quality bronze, making it compatible with the most common refrigerants in commercial and industrial refrigeration. Bronze also has good compatibility with compressor lubricating oils mixed with the refrigerant in the circuit. The plunger is made of stainless steel, which resists corrosion from the process fluid.

The seal is made of a material specific for refrigerants, which guarantees chemical compatibility with freon in continuous operation. Finally, the coil is encapsulated with IP54 protection, which is suitable for machine rooms with moderate humidity.

Technical Specifications

Voltage Selection

24 VDC is the standard voltage in modern refrigeration electronic controllers, making it the most common option in new installations with electronic control. 110 VAC, on the other hand, is for systems with conventional electrical control where that voltage is available in the panel. Both options are also available in both diameters.

Refrigerant Compatibility

This solderable freon solenoid valve is compatible with the most commonly used refrigerants in commercial and industrial refrigeration. The main ones are listed below:

• R22 — classic freon which, although being phased out, is still present in existing systems under maintenance
• R134a — standard refrigerant in automotive refrigeration and also in commercial low-temperature applications
• R404A and R507A — most used in cold rooms and also in commercial supermarket display cases
• R410A — standard refrigerant in modern air conditioning systems, making it the most common in new construction

However, for natural refrigerants such as NH3 (ammonia) or CO₂ (R744) at high pressure, specific models should be consulted with Cematic's technical team, as they require different materials and working pressures.

Applications of the Solderable Freon Solenoid Valve

New Commercial Refrigeration Installations

The solderable freon solenoid valve is the standard component in new commercial refrigeration construction. By being soldered directly to copper piping, it eliminates mechanical joints that could be leak points. For this reason, it is preferred by installers in projects involving refrigerated display cases, cold storage rooms, and walk-in coolers where circuit hermeticity is critical.

Commercial and Industrial Air Conditioning Systems

In air conditioning installations with soldered copper pipes, this solenoid controls the refrigerant flow to the evaporator according to cooling demand. Therefore, it allows precise control of system capacity. Additionally, its NC closure protects the evaporator from refrigerant flooding during compressor shutdowns.

Defrost Cycles in Cold Rooms

During defrost cycles, it is necessary to cut off the refrigerant supply to the evaporator. Consequently, this NC solenoid performs that cutoff when it receives the signal from the defrost controller. This way, the evaporator can be heated to remove accumulated ice without refrigerant continuing to flow into it.

Heat Recovery for Domestic Hot Water

In condenser heat recovery systems, this solderable freon solenoid valve controls the flow of hot refrigerant to the domestic hot water heat exchanger. Therefore, it regulates the energy transfer between the refrigeration cycle and the hot water circuit. Likewise, being solderable, it guarantees a permanent and leak-free installation at the hottest point of the circuit.

For the complete range of solenoid valves, see solenoid valve collection →