Sanhua RFKH03-4.8-406A Thermostatic Expansion Valve – R404A/R507A, Range B (−60…−25 °C), MOP −20 °C, 1/2" Flare

Sanhua RFKH03-4.8-406A, R404A / R507A refrigerant-specific thermostatic expansion valve (TXV). It has two important differences from other RFKH models: Range B low-temperature range and MOP function.

Range B + MOP: For Deep Freezer Applications, with Compressor Protection

1) Range B (−60 … −25 °C): The thermal charge of this valve is set for deep freezer temperatures. Standard Range N valves are for −40 … +10 °C and cannot deliver correct superheat at such low evaporating temperatures. In Range B models, the fluid temperature goes down to −60 °C.

2) MOP = −20 °C: MOP (Maximum Operating Pressure) prevents the evaporating pressure from rising above a certain value. When a cold system runs while still warm at initial start-up or after defrost, the evaporating pressure rises and the compressor motor is overloaded. A valve with MOP throttles at that moment and protects the compressor motor. Range N models do not have this function.

Technical Specifications (Official Sanhua Datasheet R2511, Tab. E)

• Model: Sanhua RFKH03-4.8-406A | Sanhua part no: 10201038202
• Refrigerant: R404A / R507A
• Evaporating Range: Range B: −60 … −25 °C
• MOP: −20 °C (maximum operating pressure limiter)
• Rated Capacity: 4.8 USRT (≈ 16.9 kW)
• Equalization Type: Internal equalization (no separate equalizer connection on the body)
• Connections: flare / flare — inlet 3/8" flare · outlet 1/2" flare (threaded)
• Max. Working Pressure (PS): 4.6 MPa (46 bar)
• Ambient Temperature: −35 … +55 °C | Fluid Temperature: In Range B models −60 … +70 °C
• Capillary Tube: 1.5 m, stainless steel capillary and sensing bulb
• ⚠️ Orifice NOT INCLUDED. Scope of delivery: valve body + bulb clamp. The orifice must be ordered separately (0X ~ 6, available on our site). R404A/R507A orifice capacities (kW): 0X 0.7 · 0 1.4 · 1 2.8 · 2 4.0 · 3 6.8 · 4 10.8 · 5 14.1 · 6 16.8 — details in the 2nd image
• Certificates: UL/CSA · PED declaration

• 🔧 Select the correct Range. Sanhua produces four ranges: N (−40…+10 °C) · NM (−40…−5 °C) · NL (−40…−15 °C) · B (−60…−25 °C). A valve in the wrong range cannot hold superheat at the system temperature.
• ⚠️ This valve must not be used in normal cold rooms operating ABOVE −25 °C — Range N models are suitable for those applications.
• The MOP value is selected according to the system's evaporating pressure; an MOP lower than necessary throttles the valve unnecessarily in normal operation and reduces capacity.
• 🔧 Sensing bulb: it is clamped to the suction line on a horizontal section at the 3 or 4 o'clock position, with full contact with the pipe, and insulation is wrapped over it. Insulation is especially important in low-temperature applications.
• Do not overtighten the flare connection; applying a drop of refrigeration oil to the seal surface improves sealing.