Sanhua RFKH03-4.8-21A Thermostatic Expansion Valve – R404A/R507A, Internal Equalizer, 1/2" Flare Outlet, 4.8 USRT

Sanhua RFKH03-4.8-21A is a thermostatic expansion valve (TXV) made for R404A/R507A refrigerant. It continuously adjusts the refrigerant flow entering the evaporator according to the superheat at the evaporator outlet.

Internally Equalized Body (No Equalizer Port): For Evaporators with Low Pressure Drop

This model is internally equalized: there is no separate equalizer connection on its body, and the valve takes the pressure at the evaporator inlet as its reference. It works correctly on single-circuit evaporators with low pressure drop; since it has fewer connections, installation is also simple.

⚠️ When is internal equalization NOT ENOUGH? If the evaporator has a distributor, is multi-circuit, or is a long/high-pressure-drop circuit, an internally equalized valve opens less than necessary and superheat control goes off. In these cases the externally equalized (E) version should be selected — it is available in our catalog.

Technical Specifications (Official Sanhua Datasheet R2511)

• Model: Sanhua RFKH03-4.8-21A | Sanhua part no: 10201028402
• Refrigerant: R404A/R507A
• Rated Capacity: 4.8 USRT (≈ 16.9 kW)
• Equalizer Type: Internal equalizer (no equalizer connection)
• Connections: flare / flare — inlet 3/8" flare (flare nut) · outlet 1/2" flare (flare nut)
• Evaporating Temperature Range: −40 … +10 °C (Range N)
• MOP: None — this variant is manufactured without the MOP function (Tab. A)
• Max. Working Pressure (PS): 4.6 MPa (46 bar)
• Ambient Temperature: −35 … +55 °C | Medium Temperature: −40 … +70 °C
• Capillary Tube: 1.5 m, stainless steel capillary and sensing bulb
• Thermostatic Charge: Cross charge — stable superheat across the entire evaporating range
• ⚠️ Orifice NOT INCLUDED. Datasheet scope of delivery: valve body + bulb clamp. The capacity is determined by the orifice, which must be ordered separately (0X ~ 6, available on our website). Orifice capacities for R404A/R507A (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 — full table in the 2nd image
• Certificates: UL/CSA · PED declaration

• 🔧 Code breakdown: RFKH = thermostatic expansion valve · 03 = R404A/R507A · NO letter E = internal equalizer · 4.8 = rated capacity (USRT) · last digits variant/connection.
• ℹ️ The "A" suffix indicates the new generation. Sanhua has updated the RFKH series; in the current catalog all codes are published with the A suffix.
• 🔧 Mount the sensing bulb correctly: it is clamped to the suction line, on a horizontal run, at the 3 or 4 o'clock position with full contact to the tube, and covered with insulation. If it is mounted under the tube (6 o'clock), oil accumulation causes false readings.
• Do not overtighten the flare connection; applying a drop of refrigeration oil to the sealing surface improves leak tightness.
• ⚠️ Refrigerant compatibility: This valve is charged for R404A/R507A; it must not be used in a system with another refrigerant — the thermostatic charge is different and superheat control will be off.